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400ex jetting and carb tuning
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Posted by: FoxHondaRider
Post your mods and what jet brand and size you are using. I would also include and estimated riding temperature for that jetting and elevation. Ask questions if you dont know or you're unsure and cant find what your looking for because there is always someone willing to help.
Heres a Conversion Chart comparing different brand jets. Please remember different taper needles are used in most other kits other than Keihin (OEM).
Width------Keihin # -- DynoJets # -- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
0.0540---- 140--------- 130--------- 121.9
0.0550---- 142.5------- 132--------- 123.8
0.0560---- 145--------- 134--------- 125.6
0.0570---- 147.5------- 136--------- 127.5
0.0580---- 150--------- 138--------- 129.4
0.0590---- 152.5------- 140--------- 131.3
0.0600---- 155--------- 142--------- 133.1
0.0610---- 157.5------- 144--------- 135.0
0.0620---- 160--------- 146--------- 136.9
0.0630---- 162.5------- 148--------- 138.8
0.0640---- 165--------- 150--------- 140.6
0.0650---- 167.5------- 152--------- 142.5
0.0660---- 170--------- 154--------- 144.4
0.0670---- 172.5------- 156--------- 146.3
0.0680---- 175--------- 158--------- 148.1
0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5
Posted by: hornetgod13
416EX 11:1 Wiseco Piston, Stage 1 Hotcam, HMF Slip On (quiet core installed), Stock Header Welds Ground Down, EHS Racing Lid, Snorkel Removed and Snokel Hole Plugged, UNI Filter.
Riding Temperature: 60-90 degrees
Riding Altitude: 25-1000 feet above sea level
Jetting: 42K Pilot, 162K Main Jet, Clip on 4th Slot Down, and Fuel Screw 1 3/4 turns out from lightly seated.
Posted by: BigBore24
440 big bore11:1 fmf slip on k&n + pre filter no airbox port n polish stg 3 hotcams 450r carb
450r carb settings
155 pilot
210 main
4th clip
2 1/2 turns on a/f screw
Posted by: BigBore24
ahh yeah....all keihn jets
riding temp. 40-90 deg F
elevation ????? Franklin IN
Posted by: RaginRedneck
07 400EX
DG X2 Slip on Exhaust
K&N Air Filter (Lid Box is ON)
Moose Ignition Box
DynoJet Kit:
Main: 142 main(155 Keihn Eqv.)
Pilot: 40
Needle: 3rd needle seat I believe,
2 1/4 turns out on A/F Screw
Avg Temp: 40-85 Degrees
Riding Elevation: 0-2000
Posted by: 400sEXridr
11:1 406
Hotcams Stage 2
HMF full system
airbox lid removed
normal riding temp~70*F
elevation 700 ft
all Keihin jets
170 main(slightly rich)
stock pilot(38)
4th needle clip
fuel screw about 2 1/4 turns out
does anyone know an easy way to find elevation?
ok thanks guys
Posted by: hungus07trx400
Go to wunderground.com and type in your city/state. It gives everything, including elevation.
HMF Slip on
Uni foam filter
K and N Powerlid
Keihin jets 40 pilot, 155 main
1300 feet down to about sea level. (New Hampshire- Connecticut)
Posted by: FoxHondaRider
quote:
Originally posted by 400sEXridr
does anyone know an easy way to find elevation?
Google Earth can tell you what i is or a really good estimate anywhere in the world. You could also try googling your town or where you ride (EX: "Elevation of Brooksville, FL")
Posted by: bdtoady22
99 400
hmf slip on
welds ground down in head pipe
stock air filter and box
152 main kehien
Posted by: bdtoady22
38 pilot
jetting seems spot on by plugs at 50 -80 degrees
900ft
Posted by: TRXRacer1
10:1 Wiseco 416cc, Stage 1 Hotcams, Stock headpipe with header mod, PC T4 slip-on,
Moose uni-style filter, air box lid on, Keihin jets in a STOCK carb. Riding elevation varies from 600-1000ft.
On gasoline:
Winter 0-40 degrees
155 main
Dynojet needle 4th clip from top
40 pilot
3.5 turns out on the mix screw
On gasoline:
Summer 50-90 degrees
152 main
Dynojet needle 3rd clip from top
38 pilot
3.5 turns out on the mix screw
On E85:
Winter 0-40 degrees
185 main
Dynojet needle 5th clip from the top
52 pilot
1-3/4 turns out on the mix screw
Posted by: FoxHondaRider
anyone with 400ex carb questions post them in here and read through other post to look for the range of jets you think you may need or you should try. The more post and questions, the more usefull this will be.
Posted by: FoxHondaRider
heres a question of my own that maybe others can help with. I'm pretty knowledgeable when it comes to engines and carbs. 3 weeks ago it was around 10 degrees cooler. My jetting was so perfect and my quad ran so smooth. Now that is 10 degrees or more warmer with more humidity stabbing the gas creates a bog where it wants to stop the engine. Sounds like it chokes. What do you guys think to lean or too rich? I'm thinking bigger main because I have the needle on the 4th clip. So i'm thinking richen it up. Or is it running too rich when i stab the gas flooding the motor?
Posted by: BigBore24
i would say you are too rich. if you notice trxracers jetting he is jetted higher in the winter than in the summer. when the air is colder you will require more fuel. now that it is warming up you can proly cut the fuel back a bit
Posted by: FoxHondaRider
I originally had a bog like this before when 1st jetting and all I did was raise the needle and problem solved it ran great. Now its doing it again so now you think its too much gas? Tomorrow I am going to set the needle back to the 3rd clip and see what happens. If that doesnt cure it then I will go with changing jets.
Posted by: bigredisb
any suggestions for jetting a 07 that runs a EHS open airbox lid, ground down header welds at 200ft to 1000ft elevation?
Posted by: SG1
06 400ex:
Around Dallas TX
Elevation 500FT to 1000FT
EHS Racing Air box lid
EHS Stock Exhaust Cap
Uni Filter with Outerwear's Pre-Filter
Jetted Keihin 150Main, 42Pilot
Stock Needle Setting
Fuel Screw Stock Setting
Posted by: DementeD
ill be honest i dont know the jetting ..but i removed the choke yesterday and adjust the fuel screw 2 turns
its running better then it was before adjusting the fuel screw but doesnt seem to be running better then before removing the choke
also i adjust the valves back to spec..they were loose by a good bit..mainly the exhaust valves..i could fit a .008 feeler guage in there...i only had 004 and 006 so i had to go in between..basically to tight for a 006 but loose for an 004
anyway the intake should be spot on..a little tighter then it was before
i believe before the screw was around 1.5-1.75 turns
so any suggestions ill try them out thanks 
Posted by: FoxHondaRider
quote:
Originally posted by DementeD
ill be honest i dont know the jetting ..but i removed the choke yesterday and adjust the fuel screw 2 turns
its running better then it was before adjusting the fuel screw but doesnt seem to be running better then before removing the choke
also i adjust the valves back to spec..they were loose by a good bit..mainly the exhaust valves..i could fit a .008 feeler guage in there...i only had 004 and 006 so i had to go in between..basically to tight for a 006 but loose for an 004
anyway the intake should be spot on..a little tighter then it was before
i believe before the screw was around 1.5-1.75 turns
so any suggestions ill try them out thanks
Is it running worse than before removing it through the whole RPM range or just idle and such?
Posted by: ELORDUY400
i gota a stock 400ex with KnN, amr revbox , and the baffle taken out and i want to jet it but idont know what to jet it 2 does anybody know what i should jet it 2?????? i live in miami so its hot
Posted by: Shaun Martens
i got a 2005 ex. k&n filter and powerlid, yoshi RS3 full. i'm using a dynojet needle and main. wut should i jet it at. i think it has a 146 main and it smokes black when i rev it up.
Posted by: FoxHondaRider
for dyno jet i want to say something higher like a 165 or something. Dynojet confuse me a bit because of the needle taper.
Posted by: FoxHondaRider
quote:
Originally posted by ELORDUY400
i gota a stock 400ex with KnN, amr revbox , and the baffle taken out and i want to jet it but idont know what to jet it 2 does anybody know what i should jet it 2?????? i live in miami so its hot
try a 152 keihin
Posted by: sprayedgt
2008 400ex, UNI filter,stock air box with lid, Sparks Key Advance, full Yoshi RS-3 Carbon Fiber Exhaust. I ride usually around 300-500ft. What jets do you think i need? Putting it all on this week and would like to get everything ready. Thanks.
Posted by: FoxHondaRider
with the lid on maybe a 155 with it off I would say a 158 or 160 keihin. When you go to buy jets buy a range. Since you have a full exhaust I would do myabe 155, 158, 160, 162, 165. Buy a range and work with it.
Posted by: sprayedgt
What about the pilot, needle, and the fuel screw? There wasn't anything in the Yoshimura box or paper work about jetting or anything, just how to repack and keep it clean
Posted by: FoxHondaRider
pilot maybe a 40 and the needle you will have to see on how it runs. Whether it bogs down or not. Fuel screw I dont think you would have to touch. I didnt when jetting.
Posted by: sprayedgt
Ok thanks, I really appreciate it. I'll give it a try this weekend
Posted by: Cool Guy07400EX
2007 400EX
Mods= Curtis Sparks Big Core full system, K&N air filter, No airbox lid, and the choke is removed.
Jetting= 155 Main, 42 Pilot, Air/Fuel screw is 2 1/2 turns out, and the needle is stock.
I live in Phoenix, Arizona so my elevation is close nothing, zero, zip, nada! haha
Posted by: SG1
I am going from east Dallas tx which is around 450ft elevation, to Smithville OK
which is around 1010ft elevation.
I am running this setup:
EHS Racing Air box lid
EHS Stock Exhaust Cap
Uni Filter with Outerwear's Pre-Filter
Jetted Keihin 150Main, 42Pilot
Stock Needle Setting
Fuel Screw Stock Setting
Do I need to re-jet leaner to 148 Main,
38 Pilot? Which is back to stock.
Posted by: SG1
Does anybody and any advice?!
Posted by: FoxHondaRider
with about a 560ft difference I cant see there being too much change. I would leave what you have in. 150 is just 1 size bigger than stock and you have an open air box lid basically. Unless the temperature difference is a lot different then you would need to rejet or make small chnages like the fuel screw or something.
Posted by: SG1
Thanks Foxhondarider
I think I might be a tad rich for summertime so I was thinking of going to a 40 pilot. Because it starts and idles ok but when I press on the gas it kills but after it warms up it's fine. So i think I am rich on the pilot. Of coarse now that I think about this it doesn't make sense. After it warms up it's richer because the motor is hotter. So therefore I must be lean on the pilot. I'm not sure please help.
Posted by: SG1
Any Ideas?
Posted by: drew3623
Ive been reading over all these threads and I bought a lexx slip on. I know alot of you dont like them, but it fit my budget right now. That is all the mods I have done. Stock filter and all. I went to the local honda dealer and another shop and they both told me that I dont need to rejet. My jets are stock right now. I bought a 150 main and Im going back to get a 40 pilot anyways. Everything i read on here says that you should always rejet. Oh, one of them also told me that I should actually go smaller than stock on my main My elevation is around 500ft and temp is going to be 90 this weekend. Im in St. Louis. Im going tomorrow so any quick advice would be awesome. Thanks
Posted by: CGriff
I just bored out my cylinder and put a 426 kit with stg 1 hotcam in the beast, at first I ran Dyno jets stg ones specs with the airbox lid on; they suggsted the needle clip on the 3rd groove, with a 146 main jet and the fuel screw 3.5 turns out. So I ran that for a day and it worked amazing. The next day I got curious about their stage 2 specs with the airbox lid off, so I threw in their 170 main jet and took off the airbox lid.... in all honsetly I think it had more snap with the stage 1 specs.
Posted by: FoxHondaRider
quote:
Originally posted by CGriff
I just bored out my cylinder and put a 426 kit with stg 1 hotcam in the beast, at first I ran Dyno jets stg ones specs with the airbox lid on; they suggsted the needle clip on the 3rd groove, with a 146 main jet and the fuel screw 3.5 turns out. So I ran that for a day and it worked amazing. The next day I got curious about their stage 2 specs with the airbox lid off, so I threw in their 170 main jet and took off the airbox lid.... in all honsetly I think it had more snap with the stage 1 specs.
it was probally rich on the stage 2
Posted by: Honda#4
Glad to see the conversion chart I was just gonna search for it.
Posted by: SG1
quote:
Originally posted by SG1
Thanks Foxhondarider
I think I might be a tad rich for summertime so I was thinking of going to a 40 pilot. Because it starts and idles ok but when I press on the gas it kills but after it warms up it's fine. So i think I am rich on the pilot. Of coarse now that I think about this it doesn't make sense. After it warms up it's richer because the motor is hotter. So therefore I must be lean on the pilot. I'm not sure please help.
I looked at my spark plug and found it be be ok as far as being rich. The spark plug had some black on it but for the most part it was good meaning not a whole lot of black stuff on it. It even had a white spot on it. So I think I am jetting just right. So if I go up 600ft in elevation there will be less air or the air will be a little thinner. So then there will be more gas going in and it will be richer or leaner?
Posted by: Speedy 400ex
I am putting that air box lid mod on my bike and i was wondering what jets i should get? it has a k&n and a white bros E searies on it also. its been jetted for those. im around sea lvl to 2000ft
thanks
Posted by: leasureryan
Motor mods are EHS lid with Uni filter, and HMF full exhaust system. F'n loud! Simple, yet efficient. Running a 93 octane & 110 octane 50/50 mix. Have the carb jetted at a 165 main and a 45 pilot....all Kehin ofcouse.....none of those junker off brands...lol Air screw is 2.5 turns out. Runs SUPER strong! No hesitations.....still trying to tune out the slight back firing from the full system being added, previously running stock header and FMF powercore 4 at a 152 main and a 40 pilot, air screw 1.5 out. I can tell a huge differance!
Posted by: leasureryan
IMO........K&N filters are the absolute WORST filter that you can use for dirt applications. I have seen so many quads and dirt bikes come through the service dept at work, with BOULDERS in the carb and intakes. Those things were made for car and street bike applications....not dirt. They just figured that they would expand thier prodution, and make a little extra cash....and hell.....they already had a popular well known name in performance filters....right???....they must be great.....right????......WRONG!!!
Outerwares or not.......K&N=J&U&N&K
Posted by: FoxHondaRider
quote:
Originally posted by leasureryan
IMO........K&N filters are the absolute WORST filter that you can use for dirt applications. I have seen so many quads and dirt bikes come through the service dept at work, with BOULDERS in the carb and intakes. Those things were made for car and street bike applications....not dirt. They just figured that they would expand thier prodution, and make a little extra cash....and hell.....they already had a popular well known name in performance filters....right???....they must be great.....right????......WRONG!!!
Outerwares or not.......K&N=J&U&N&K
they work good for me. Lets not turn this into a air filter debate just jetting.
Posted by: my88r
for you, no air box lid guys. much did it lean out the jetting. I'm saying maybe 2 sizes. but what do you guys say. my jetting is still a little on the rich side.
Posted by: FoxHondaRider
quote:
Originally posted by Speedy 400ex
I am putting that air box lid mod on my bike and i was wondering what jets i should get? it has a k&n and a white bros E searies on it also. its been jetted for those. im around sea lvl to 2000ft
thanks
air box lid mod? cutting it and putting an outerwear on it or just taking it off? either way maybe bump up the main 1 size and see how it runs. Checking the spark plug is a great thing to do i just wish the spark plug wasnt so hard to get at.
Posted by: sprayedgt
What about taking your spark arrestor out? Do you need to re-jet?
Posted by: ZJTurbo
I just ordered. Lexx slipon/ Jet kit from jets R us and am removing the choke. K&N with outwears no air box cover. I am guessing 42 pilot with a 155-160 main> o elevation??
-Ben
Posted by: FoxHondaRider
quote:
Originally posted by sprayedgt
What about taking your spark arrestor out? Do you need to re-jet?
I highly doubt it. Any reason for taking it out?
Posted by: FoxHondaRider
quote:
Originally posted by ZJTurbo
I just ordered. Lexx slipon/ Jet kit from jets R us and am removing the choke. K&N with outwears no air box cover. I am guessing 42 pilot with a 155-160 main> o elevation??
-Ben
for just a slip on and those mods I think you would be better suited for the jets 150 - 160. Order a range incase of future mods or anything else it doesnt cost much more and its cheaper to order them at once. Check your elevation and let us know what it is.
Posted by: ZJTurbo
I am at sea level. I live in Rhode Island
Posted by: FoxHondaRider
Ben, I think a 152 or 155 main should do the trick. Try both and see which one runs better.
Posted by: ZJTurbo
Thank alot Fox I appreciate it!
-Ben
Posted by: sideways
found a lot of good information on this thread!!! now my question......
I just got done rebuilding my 400ex. here's what i did:
416 bore kit (10.5:1)
hotcams stage 1
polished valves, did not port
Powerbomb head pipe,
FMF powercore 4 slip on
WB cdi box
air box lid on, 7-1" filtered holes, snorkel on
uni air filter
elevation: roughly 300' above sea level
do all trail riding/ hare scrambles, no track at all
the FMF slip on came with jets, they were installed last year when i got the slip on, not sure what they are, i'll have to check.
i finally got the entire bike back together tonight, and it fired up first time! thank god....
so back to the question at hand: what would be a good starting point for jetting?
Posted by: hornetgod13
quote:
Originally posted by sideways
found a lot of good information on this thread!!! now my question......
I just got done rebuilding my 400ex. here's what i did:
416 bore kit (10.5:1)
hotcams stage 1
polished valves, did not port
Powerbomb head pipe,
FMF powercore 4 slip on
WB cdi box
air box lid on, 7-1" filtered holes, snorkel on
uni air filter
elevation: roughly 300' above sea level
do all trail riding/ hare scrambles, no track at all
what would be a good starting point for jetting?
42K Pilot, 165K Main, and Needle Clip on 4th Slot Down.
Posted by: honda400ex2003
My 416 has 170 k., 2 notches on stock needle, 2.5 turns on fuel, 38 pilot with the air box lid off. I am at about 1000 ft. I am in northern wi. Thanks Steve
Posted by: FoxHondaRider
maybe you guys can help me out on this one. My quad wont start on its own, I have to give it some gas otherwise it dies and when i do theres a popping or choking noise which is maybe a carb backfire? anyways why doesnt it start good, why do I have to give it gas, why is it making that noise? It should be the pilot/fuel screw setting that is wrong but which way do I go. Is it rich or lean thats causing it? The rest of my jetting is fine and once you get it warmed up from holding the throttle then it will idle on its own and it runs perfect. When its hot it starts so easy.
Posted by: leasureryan
quote:
Originally posted by FoxHondaRider
maybe you guys can help me out on this one. My quad wont start on its own, I have to give it some gas otherwise it dies and when i do theres a popping or choking noise which is maybe a carb backfire? anyways why doesnt it start good, why do I have to give it gas, why is it making that noise? It should be the pilot/fuel screw setting that is wrong but which way do I go. Is it rich or lean thats causing it? The rest of my jetting is fine and once you get it warmed up from holding the throttle then it will idle on its own and it runs perfect. When its hot it starts so easy.
what size and type pilot do you have, and what clip is needle on. Hard start is useualy lean on pilot, but again, it may be rich. We need specs and mods. How many turns out is air screw? Stock is 1 1/2 turns out.
I thought you knew your jetting?......j/k
Posted by: FoxHondaRider
quote:
Originally posted by leasureryan
what size and type pilot do you have, and what clip is needle on. Hard start is useualy lean on pilot, but again, it may be rich. We need specs and mods. How many turns out is air screw? Stock is 1 1/2 turns out.
I thought you knew your jetting?......j/k
lol yeah i thought i knew my own jetting but i discovered a flaw. 42 pilot turns out i dont know i assume stock. I'm thinking rich but i wanted to hear others opinion.
Posted by: FoxHondaRider
so is the "cough" through my carb when i try to start it rich on the pilot/fuel screw? or is there another problem
Posted by: blankenship
i have a 2001 440 ex stage 2 hotcams and a full dg xcelerator pipe what jets should i go with havent ran bike sence i put it together where should i start??? never jetted a bike in my life if that helps any
Posted by: speedfoxracing
stock with pro circuit and 152 main jet
Posted by: ATW55
what do you guys think i should jet mine i got a 05 40ex with a hmf slip on and every thing else is stock i live about 600 ft above sea level? what do you guys think about dial a jet are they worth the money?
Posted by: speedfoxracing
just get a kehin jet and i would say 152-155 i have a pro circuit and thats it and i,m runin a 152
Posted by: ATW55
quote:
Originally posted by speedfoxracing
just get a kehin jet and i would say 152-155 i have a pro circuit and thats it and i,m runin a 152
i got a 155 kehin in it and it is blowing white smoke after i get it warmed up
Posted by: speedfoxracing
is it burning oil ? but that should be black right and how does she run? any boging or lag ?
Posted by: ATW55
quote:
Originally posted by speedfoxracing
is it burning oil ? but that should be black right and how does she run? any boging or lag ?
it runs fine it is jjust blowing white smoke after 45 min to a 1hr and ant burnin oil or any thing
Posted by: speedfoxracing
idk y it would be blowing white smoke usually white smoke is moisture but idk y it would only do it when its warm
Posted by: sideways
quote:
Originally posted by hornetgod13
42K Pilot, 165K Main, and Needle Clip on 4th Slot Down.
did some jetting runs on my own and was unhappy with the results i was getting, so i ended up taking it to the local shop for them to do it. here's what the final jets are in the bike:
pilot :38
main: 160
needle clip: 4th slot down
fuel screw 2.5 turns out
this is a lot different than what was suggested for me to put in. not sure if it's right, but so far it runs great, easy starting without the choke, crisp, good throttle response, no bogging, no smoke.
havent checked with a new plug yet, hopefully this afternoon i can get some runs in for a plug check.
Posted by: zrpilot
quote:
Originally posted by sideways
this is a lot different than what was suggested for me to put in.
Actually the suggestions given were not that far off. A 5 point main adjustment, IMO, would be hardly noticeable by the average rider. A pro like Ballance, yeah maybe, but not me on my 400EX....
If the shop did your jetting on a dyno, then it will be probably dialed in great.
Here is a dyno run done on my quad that shows a 6 point main change and you will see VERY LITTLE power difference. However notice the AF ratio did change.
Posted by: Honda#4
I need a bit of help with jetting also, just put in a dj155 main, 42 pilot, 4th slot on clip and the A/F screw one turn out off stock, still got a bit of backfire off half thottle and a slite knock coming to a idle when stoping, running 89 now but thinkin I need 93.
Posted by: sideways
quote:
Originally posted by zrpilot
Actually the suggestions given were not that far off. A 5 point main adjustment, IMO, would be hardly noticeable by the average rider. A pro like Ballance, yeah maybe, but not me on my 400EX....
If the shop did your jetting on a dyno, then it will be probably dialed in great.
Here is a dyno run done on my quad that shows a 6 point main change and you will see VERY LITTLE power difference. However notice the AF ratio did change.
i'm pretty sure they didnt do it on a dyno, i dont think they have one, if they do, its very well hidden!! pretty sure it was sound of the engine/seat of the pants jetting, which doesnt seem to mean much to me if there is that little difference on a dyno, how can you tell by your pants? didnt get any time to do a plug check today, maybe tomorrow.
Posted by: alex10
What should I run for a
416 11:1 piston
Stage 2 hotcams
Open airbox
Uni air-filter
White brothers slip on
1,300ft of elevation
Temps 30-80f
I'm going to be doing this in a couple weeks just wondering what I should try first. thanks
Posted by: alex10
?
Posted by: honda400ex2003
This is what I am at now. Check my sig. I live in northern WI, at about 1200 ft. It seems to run great for me. Steve
Posted by: FoxHondaRider
so i've come to find out my slide only goes up 6-7/8ths of the way. It doesnt go all the way in. So basically my full throttle isnt the engines full potential (man does that look bad for all of those I raced against and won lol). So my question is how do I make it so my slide goes all the way up? Is the cable stretched? Is there a stopper that needs to be adjusted?
Posted by: FoxHondaRider
anyone?
Posted by: RaginRedneck
foxhondarider,
Posted by: RaginRedneck
foxhondarider,
I wish I could help, but I'm not sure. I would start with all adjustments from the throttle back and see where you get, maybe someone more educated than I can help you out.
Posted by: FoxHondaRider
I dont know where it is to adjust it, is it behind the black cover on the right side of the carb or is it in the throttle assembly on the bars?
Posted by: DuwBra
Actually im just looking for suggestions. I have a hmf slip on, k&n filter with the air box lid removed and a white bro rev box. We just switched to a 150 main and the rest i believe is stock settings and it wants to bog about 3/4 throttle, any ideas?
Posted by: FoxHondaRider
with almost those exact same mods I was using a 155 main jet
Posted by: FoxHondaRider
update, my throttle would only push the slide 6-7/8ths open so I wasnt in FULL thottle i was between 100% full and when the needle comes compelely out. So I was running 42k pilot, 155k main, and the needle on the 4th slot when the throttle wouldnt go all the way up. Now I adjusted it today and to my surprise I had to rejet I threw in a bigger main and now it runs better than ever. So the update is my main jet is now a 158k.
NEW:
main: 158 keihin
pilot: 42 keihin
needle: 4th slot
elevation: 50 - 200 ft above sealevel
average average temperature: 71 degrees
average high: 82 degrees
average low: 61
Mods:
-HMF slip on
-Choke plate removed
-header welds ground down
-K&N airfilter w/ outerwear
-airbox lid removed with outerwear cover
-curtis sparks 6 degree advanced timing key
Posted by: FoxHondaRider
to perfect my jetting more the needle nows needs to be 1 slot richer but now i ran into a problem. My carb had/has some stripped/rounded brass screws. Many I have replaced with stainless steel the head of the screw broke off trying to loosen it. I got the slide out of the carb and it taken off. now i have to try and use pliers to remove the screw. My next question is. When i stab the throttle it will want to shut off. Thats why i figured go 1 slot richer on the needle. My needle is on the 4th slot doing it and now i will be on the 5th slot. That means I need a smaller needle? does this sound right to you guys? any help is appreciated
Posted by: MtnEX
I'm lost... what screw did you break?
The guy who did mine ruined my screws on the very top of the carb.
I took care of that.
As for the throttle stab thing... there's another thread in here on that.
I replied in there at length (may be worthless) and with that said, I know I have a rich condition.
Posted by: badquad
Not sure if this is the right place.
I have a 39 FCR carb.
Motor bored over 20 thousandths
Curtis Sparks X-6 pipe
Curtis Sparks Rev Limiter
Advance Key
Hot Cam Stage 1
Well here is my problem.. Bike ran fine in May when I left it, came back in August and runs like crap between 1/4 throttle to 3/4 throttle. Starts up fine, idles fine, and wide open runs fine.
When I am between 1/4 and 3/4 it runs like it has water, but I drained the tank, cleaned the carb, and the pump(diaphram) think or acc pump area. Which seems like it does not move much when I hit the throttle.
Not sure what else to do.. Even changed the plug. IT was black. But like I said, it ran fine before I shut it down in May.
I am at sea level, at temps right now at 40-55 degrees. NOt sure what my jets are,, I think I only found the main jet, that is where the needle goes in right?? is the other jet right next to it, with the slot for the screwdriver??
HELP..
Posted by: MtnEX
quote:
Originally posted by badquad
Not sure if this is the right place.
I have a 39 FCR carb.
Motor bored over 20 thousandths
Curtis Sparks X-6 pipe
Curtis Sparks Rev Limiter
Advance Key
Hot Cam Stage 1
Well here is my problem.. Bike ran fine in May when I left it, came back in August and runs like crap between 1/4 throttle to 3/4 throttle. Starts up fine, idles fine, and wide open runs fine.
When I am between 1/4 and 3/4 it runs like it has water, but I drained the tank, cleaned the carb, and the pump(diaphram) think or acc pump area. Which seems like it does not move much when I hit the throttle.
Not sure what else to do.. Even changed the plug. IT was black. But like I said, it ran fine before I shut it down in May.
I am at sea level, at temps right now at 40-55 degrees. NOt sure what my jets are,, I think I only found the main jet, that is where the needle goes in right?? is the other jet right next to it, with the slot for the screwdriver??
HELP..
Well, your problem is definately when you are on the needle.
I'd say your carb is just gunked up from sitting that amount of time.
Try some Seafoam or something like that in the gas to see if you can clear it out.
Then once it's back to running like it was... then put in a fresh plug and do a plug reading to judge how your jetting is.
Posted by: monkeyballs
Honda 400ex 2002
Full system yosh pipe (no spark arrestor)
K&N air filter w/ pre charger
No air box lid
170 main
32 pilot
air screw 3.5 turnes out
needle 3rd notch down
riding temp
10-30 degrees celsius at the moment..
winter 0 to -40
I just did this 2 days ago and I finde that im lacking a little on top end. Why is this? And I looked at the spark plug and its just perfect. To me any ways..
Posted by: FoxHondaRider
Honda said they will jet my quad and make it perfect, they have a dyno there and stuff for $68 an hour. and its how ever long it takes them to get it right. at $68 an hour that guy is probally going to move as slow as a snail and it will probally be more than that. on the plus side i found i can dyno my quad at the honda dealer and have A/F testing for $35!!!
Posted by: leasureryan
I got mine dyno last week....gained 2.5 HP!!!
Posted by: FoxHondaRider
alright so the bog/cut out i was trying to fix heres how it went. It was on the 4th slot, i moved it to the 5th and it got worse. So then I went to the 3rd and it seemed crappy too but after revving it for awhile and stuff it seemed it got better and it would go pretty good quick revving without problems. what do you guys think
Posted by: leasureryan
I don't think that a carb should act any differant 5 mins after switching needle postions, than right when it is started up. Carbs don't (aren't) really supposed to work like that. It's either better...or it's not.
Posted by: FoxHondaRider
took it for a test run with the 3rd and it lacked power and didnt get up there. I put the needle on the 2nd and it revved perfect and when i rode it it felt fine but it didnt seem to have the power it did before. i'm lost because it was running fine before i went on vacation it seemed perfect. I come back and start having bogging and stuff problems. i dont think gas can go bad that quick but something isnt right.
Posted by: monkeyballs
Zomfg! I jetted my carb like 5 days ago and I took it for a spin on a dirt road and I thought I was lacking top end... Then today I took it for a rip on the hwy and holy crap! Pops cat walks in 5th pretty ez.. For a 400ex.. With just no air box lid k&n and pipe lol. Crazy! Im verry happy !
Posted by: apachepride
hope this is the place for this i have the stage 2 dyno jet 170 main stock pilot choke removed, removed air box lid header welds ground aftermarket filter tc 924 cam and sparks degree key im getting ready to put the 440 toghether im in KS 1350 elevation i think compression is 11.5.1 thanks
Posted by: dave4881
BTW, what is stock jetting for an 05 400EX?
Are you guys using the Keihin numbers when you discuss jet sizes?
Posted by: dave4881
quote:
Originally posted by leasureryan
IMO........K&N filters are the absolute WORST filter that you can use for dirt applications. I have seen so many quads and dirt bikes come through the service dept at work, with BOULDERS in the carb and intakes. Those things were made for car and street bike applications....not dirt. They just figured that they would expand thier prodution, and make a little extra cash....and hell.....they already had a popular well known name in performance filters....right???....they must be great.....right????......WRONG!!!
Outerwares or not.......K&N=J&U&N&K
Agreed! I won't even run one in my street machines!
Posted by: sprayedgt
quote:
Originally posted by dave4881
BTW, what is stock jetting for an 05 400EX?
Are you guys using the Keihin numbers when you discuss jet sizes?
I believe its a Keihin 38 pilot and 148 main. Don't know why people use anything other than Keihin when they jet.
Posted by: dave4881
quote:
Originally posted by sprayedgt
I believe its a Keihin 38 pilot and 148 main. Don't know why people use anything other than Keihin when they jet.
Thanks! BTW, which model Keihin carb does the 400EX have?
Posted by: capecod400ex
2001 416ex
stage 2 hot cams, timing chain, 10:1 comp piston running KN filter and KNpowerlid,DG full system
seems a bit lean idk how its currently setup but what should it be
Posted by: kinnybee
Hoping someone can help me out...
The problem is my 2000 400ex stutters at full RPM. I spent this afternoon and evening rejetting it. In deference to my neighbors, I've only been able to test up to third gear, and she accelerates great to the top of each gear, but then stutters at the top. I haven't adjusted the needle because I'm assuming it won't matter since the problem occurs at WOT where the needle is not affecting the fuel flow anyway.
I have run tests with Dynojets: 138, 145, 155, 165, and 170. There has been no change in the stuttering. I wind out first gear and it accelerates great but then stutters at full rpm, then second gear is great acceleration and then stutters at full rpm, then third is great and then stutters at full rpm. Since a DJ170 is equivalent to a keihin 190, I'm doubting I need an even larger main jet, But maybe I do? I checked the plug after a minute or two at full rpm in neutral with the 145 jet and it was black but not sooty wet, so I'm assuming I'm not lean at 170. The stuttering is mild, like its "almost there" but just won't top out. I hardly notice it on the dirt trails, but it will be a killer on dunes if I cant get full rpm.
As far as airflow, the guy I bought it from said he did something to the exhaust headers. Not sure if he ground the welds or what. He also said the exhaust was stock, but the core and spark arrestor have been removed, so its basically a straight pipe (I know, I know, I'll add a slip on eventually, but cant afford it right now). It has an old dirty K&N filter that I just cleaned and oiled yesterday, and now looks
decent. And I have the airbox lid on. I did lid tests at WOT in neutral, and had stuttering at full rpm with the lid off as well as on. No apparent difference. I changed the oil and filter too.
So am I on the wrong track? Is there something else that could be causing the stuttering at full rpm? Or do I need to buy some larger main jets and keep testing?
For added info: I am at about 60ft elevation, basically sea level, and the temp has been in the 40s. My pilot jet is a stock Keihin 38. It sometimes takes a little throttle to start so I am thinking of moving up to a 42 (since I have one to put in), but it seems to idle fine even when cold, and idles great when warm, and after idling the plug comes out grey but not burnt, so it may idle a little lean. And after coming down from WOT i get a backfire, So a 42 pilot may be better for all those reasons. In any case, this is not really my main problem.
Posted by: sprayedgt
It sounds like you're running way too rich since as soon as you get into the main jet range it falls on its face. I would say that the jetting should still need to be stock or at most one up from stock. Grinding down the welds does flow a slight bit of air more than stock, but not really enough to need a jet change even with a filter. See where your needle is and work off that. I believe it's just a needle adjustment that is needed. Oh and do yourself a favor and get some Keihin jets in the future when you need to tune.
Posted by: dave4881
quote:
Originally posted by sprayedgt
It sounds like you're running way too rich since as soon as you get into the main jet range it falls on its face. I would say that the jetting should still need to be stock or at most one up from stock. Grinding down the welds does flow a slight bit of air more than stock, but not really enough to need a jet change even with a filter. See where your needle is and work off that. I believe it's just a needle adjustment that is needed. Oh and do yourself a favor and get some Keihin jets in the future when you need to tune.
Question: Does the stock Keihin needle have different rings on it so that you can adjust it up or down by moving the e-clip? I know the Dynajet needle does. My Suzuki did not. You had to use little washers to shim it up.
Answered my own question after rejetting: No, it does not.
Posted by: sprayedgt
If it's older than a 2005 the needle is adjustable.
Posted by: kinnybee
quote:
Originally posted by sprayedgt
It sounds like you're running way too rich since as soon as you get into the main jet range it falls on its face. I would say that the jetting should still need to be stock or at most one up from stock. Grinding down the welds does flow a slight bit of air more than stock, but not really enough to need a jet change even with a filter. See where your needle is and work off that. I believe it's just a needle adjustment that is needed. Oh and do yourself a favor and get some Keihin jets in the future when you need to tune.
I put the stock jet in this morning and it still runs the same. So if I have a straight empty exhaust with no core or packing... just empty straight pipe... doesn't that increase airflow?? And is there a possibility that I might have a lack of backpressure? Does backpressure matter in small engines?
Posted by: sprayedgt
You are still limited by the stock header. Even though the welds have been ground it really does not make much of a difference in flow. The diameter is still very small. Back pressure is not as crucial in a small 4 stroke engine as it is in a 2 stroke engine. And saying the stock jet it's the original KEIHIN 148 main? I still think you need to adjust your needle. That should take care of your problem.
Posted by: kinnybee
quote:
Originally posted by sprayedgt
And saying the stock jet it's the original KEIHIN 148 main? I still think you need to adjust your needle. That should take care of your problem.
Yeah, its the keihin 148. i took off the dj adapter...
OK, I will check the needle. thanks...
Is there anything else that could cause high rpm stuttering?
Posted by: dave4881
I just installed a HMF Sport slip on with the quiet core. Cleaned the carb and rejetted with a (K) 160 Main and a 42 Pilot. Runs great. Airbox lid has 12 one-inch holes with Uni filter vents. Snorkel shortened slightly at both ends (opened up).
Elevation < 1,000 ft.
And, yes, it now starts and idles when cold. I'm happy!
Also installed a Motion Pro CR Twist Grip. Much better than that thumb thingy.
Posted by: honda440
ok i got a 400ex with stock compression and cam and i did some mods to the airbox and im runnin an akroprovic full system with the choke removed and im also at 590ft elevation.. any tips would be great....thanxs
Posted by: honda440
im really lost when everyone is talking about jets and the whole jetting deal.. anyone have any suggestions for my quad
-akroprovic full exhaust
air box lid off
snorkel off and blocked
choke removed
im at 0-2000ft so anysuggestions would be great
Posted by: dave4881
quote:
Originally posted by honda440
ok i got a 400ex with stock compression and cam and i did some mods to the airbox and im runnin an akroprovic full system with the choke removed and im also at 590ft elevation.. any tips would be great....thanxs
See my post above yours. It is a good starting point.
Posted by: dave4881
quote:
Originally posted by DuwBra
Actually im just looking for suggestions. I have a hmf slip on, k&n filter with the air box lid removed and a white bro rev box. We just switched to a 150 main and the rest i believe is stock settings and it wants to bog about 3/4 throttle, any ideas?
I'm no expert but, I would say your mainjet is too small (lean). Stock is a 148. Only going up one size (150) isn't much of a change.
I have the same mods as you, but no rev box. I'm now running a Keihin 165 mainjet and a #42 pilot, and it really hauls ***. Needle is set on the 4th slot from the top.
Make sure you clean your carb with some good (spray) carb cleaner when you have it apart. Good luck.
Posted by: MAKO19
See my mods in my signature. Nothing special just the typical bolt-ons.
I was wondering if there is a better comb as far as jets or tuning? HMF recommends 152 main and 42 pilot but at light throttle in lower gears the quad tends to stutter sometimes. Has anyone found that there is a better combo than what HMF recommends?
I have the +6 degree key to install as well but haven't done that yet. Maybe that will smooth things out a bit. More timing always did make thing run smoother. I am also running the stock air box.
Posted by: uspatriot
I have a white bros slip on exhaust and a k&n air filter.
At the beginning of the winter it wasn't running right so i took the stock 38 pilot jet put and put a 48 in.
This ran fine until now.
When ever i go and then let off the throttle it backfires a bunch of times.
Idk if its getting to much air of to much fuel, i would think its getting to much fuel because it has such a big pilot jet but someone said that if it backfires that it is too much air.
Do i have to change the pilot or main jet out?
What sizes do i need?
THnaks
Posted by: rob_990
a 38 to a 48 is a huge jump! i dont know how it could be to lean and backfiring maybe it is getting to much fuel.what size main do you have?
Posted by: uspatriot
Its a stock main. Thats what i was thinking to much fuel but then someone told me it only backfires when letting off the throttle if you are getting to much air.
Should i try a 42 pilot or somthing around there
Posted by: rob_990
yea thats weird.i only heard of it backfiring cause its too lean not rich. try it and see what happens.just dont blow a gasket
Posted by: FlewByU352
My quad runs great and has a lot of snap. My only problem is cold starting I have to keep on the gas and it will best way to describe is is cough or pop through the intake until it warms up. Is this a valve overlap? Rich? Lean? I'm pretty sure its not a leak.
Posted by: uspatriot
how can you blow a gasket by jetting wrong?
Posted by: ngates788
Jetting is really not my strong point.. i just got my motor back in my quad. It runs fine as long as its cold but as soon as it warms up it floods out and dies. I assume its running to rich and loading up in the carb. i have tried adjusting the mixture screw to no avail. im currently running a 170dj main and 44dj pilot. If I go down to a 42dj or 40dj pilot do you think this will cure my problem?
Posted by: MtnEX
What does the spark plug look like?
Yeah, I'd say try the 42 pilot jet.
Posted by: ngates788
quote:
Originally posted by MtnEX
What does the spark plug look like?
Yeah, I'd say try the 42 pilot jet.
i dont even think its run long enough to affect the color of the plug lol but im going to change out the jets and see if it makes enough difference to allow it to run for a while and find out what the problem is
Posted by: DP400
2002 Stock motor, k&n, lid on, HMF slip on, 93 Mobil octane.
Pilot K40, screw 2 turns out
Main K155
Clip last slot down on stock needle.
Still cold here in NY, Altitude is 600.
I'm still getting sputtering on decel and backfire here and there on hard decel, 2nd gear.
HMF says to stay at a stock pilot and go up to a 165/170 main, that doesn't make sense to me, anyone else? also anyone know if you can get just a smaller needle then stock at the dealer?
I may need a smaller needle, turn out screw another 1/2 turn or try the larger mains. it will be warming up here soon so it may just correct the sputtering with warmer temps. Its not as bad as when i just had the stock pilot in though.
Posted by: FlewByU352
Try adjusting your fuel screw and maybe the needle in the middle slot
Posted by: DP400
The needle was in the middle stock slot, figured I would make it richer by moving it down to stop the popping and backfiring, it did definatly help. Maybe a smaller needle would help. just a difficult time of the year right now. one day its 43 and the next 25. i'm just going to leave it now and hope that it corrects when it gets warmer out.
Posted by: jeryk
will u tell me what jets i need for mine i have no clue i wanna see how close i am on ur guys choice
Posted by: FlewByU352
is the fuel screw in for more fuel or out for more fuel? I have trouble getting my quad to start. Once it warms up it idles great and had amazing response. but when its a cold start as in no warming up 1st i have to keep starting it and feathering the gas right to get it to stay started until it warms. i dont know if its a jetting issue only because of how great the response is off idle but i'm almost thinking lean if i need to give it a little gas to stay on.
Posted by: Homerx
quote:
Originally posted by FlewByU352
is the fuel screw in for more fuel or out for more fuel? I have trouble getting my quad to start. Once it warms up it idles great and had amazing response. but when its a cold start as in no warming up 1st i have to keep starting it and feathering the gas right to get it to stay started until it warms. i dont know if its a jetting issue only because of how great the response is off idle but i'm almost thinking lean if i need to give it a little gas to stay on.
All 400ex's do it, there cold blooded thats all. Mine does it too.
Posted by: dave4881
quote:
Originally posted by FlewByU352
is the fuel screw in for more fuel or out for more fuel? I have trouble getting my quad to start. Once it warms up it idles great and had amazing response. but when its a cold start as in no warming up 1st i have to keep starting it and feathering the gas right to get it to stay started until it warms. i dont know if its a jetting issue only because of how great the response is off idle but i'm almost thinking lean if i need to give it a little gas to stay on.
Turning the fuel screw out (LH) enrichens the mixture a little, but for a better solution to the problem, change your pilot jet to a Keihin #42 and you will solve the cold starting problem. Starts easier and runs better. They are set too lean from the factory. While you're at it, I would install a 160 Main jet also.
Posted by: FlewByU352
quote:
Originally posted by dave4881
Turning the fuel screw out (LH) enrichens the mixture a little, but for a better solution to the problem, change your pilot jet to a Keihin #42 and you will solve the cold starting problem. Starts easier and runs better. They are set too lean from the factory. While you're at it, I would install a 160 Main jet also.
thanks, already have a 42 pilot, and 158 main fuel screw is out it seems quite a bit because the head is visable looking from the side. I figured it might be out too much thats why i asked.
Posted by: bdiddy72187
any suggestions for a 400 white bros. E series full exh. airbox eliminator w/ a K&N i would like to stick with Keihn jets. I ride mostly between sea level and 1000'. thanks
Posted by: dave4881
quote:
Originally posted by bdiddy72187
any suggestions for a 400 white bros. E series full exh. airbox eliminator w/ a K&N i would like to stick with Keihn jets. I ride mostly between sea level and 1000'. thanks
Running that K&N, I hope you don't ride in dusty areas. IMHO, the K&N's provide a lot of airflow but sacrifice in filtration. Dust & grit that is injested into the intake will get in to the oil. That will add a lot of wear to your engine quickly. I would recommend a Uni or Twin Air oiled air filter with an Outerwears over them.
Try a 160 mainjet Keihin) and a 42 pilot. After installing the pilot, turn the fuel screw in until it closes and then turn out 2 turns. Then run engine and adjust further using the standard procedure.
Posted by: bdiddy72187
thanks for the info! I ride the dune mostly, I have an outer wears of course. I had K&Ns on my Banshee too never had a problem. i do appreciate the concern though.
Posted by: Shaun Martens
i've got a 2005 400ex. full yoshi exhaust, stage 2 hotcam, 86mm 11:1 Weisco piston, k&N air filter, lid on, dyno jet kit. I don't know where to start for jetting. 1000 feet above sea level
Posted by: dave4881
quote:
Originally posted by Shaun Martens
i've got a 2005 400ex. full yoshi exhaust, stage 2 hotcam, 86mm 11:1 Weisco piston, k&N air filter, lid on, dyno jet kit. I don't know where to start for jetting. 1000 feet above sea level
You already have some extensive mods. Has the carb been jetted?
On the airbox, I suggest you take the lid and drill about 12 - 1" holes with a carbide step drill and install the Uni UFV filter vents. They come 6 to package and you would need two packages. This is a way of opening up the air box without sacrificing filtration. The 1" filter vents are about $11 per package. For the money it's a great way to open up the intake. I also cut 1/2" off the front end of the snorkel. But, if you ride in bogs or very deep water/mud this wouldn't be a good idea. My riding is all desert so no concerns with water. I'll try to post a pic of my airbox lid so you can see how its done.
If you carb is not already jetted, I would start with a Keihin 165 mainjet. See the first post in this thread for the conversion tables to convert to the equivalent Dynajet. As I said in other posts, I recommend the #42 pilot jet also.
Posted by: dave4881
quote:
Originally posted by FlewByU352
thanks, already have a 42 pilot, and 158 main fuel screw is out it seems quite a bit because the head is visable looking from the side. I figured it might be out too much thats why i asked.
OK, warm up your engine to normal operating temp. Let the engine idle and turn the fuel screw in (R) SLOWLY until the rpms increase slightly and then open (turn left) the fuel screw 1/4 to a half turn. This should be optimum for your setup.
If it doesn't make any changes, your carb may be dirty and need a good cleaning.
Posted by: Shaun Martens
quote:
Originally posted by dave4881
You already have some extensive mods. Has the carb been jetted?
On the airbox, I suggest you take the lid and drill about 12 - 1" holes with a carbide step drill and install the Uni UFV filter vents. They come 6 to package and you would need two packages. This is a way of opening up the air box without sacrificing filtration. The 1" filter vents are about $11 per package. For the money it's a great way to open up the intake. I also cut 1/2" off the front end of the snorkel. But, if you ride in bogs or very deep water/mud this wouldn't be a good idea. My riding is all desert so no concerns with water. I'll try to post a pic of my airbox lid so you can see how its done.
If you carb is not already jetted, I would start with a Keihin 165 mainjet. See the first post in this thread for the conversion tables to convert to the equivalent Dynajet. As I said in other posts, I recommend the 142 pilot jet also.
Its been jetted before but i don't know whats all in there right now. Where do I find those vents that you are talking about?
Is it ok to use keihin jets with a dynajet needle? would i get the keihin jet from honda?
Posted by: dave4881
quote:
Originally posted by Shaun Martens
Its been jetted before but i don't know whats all in there right now. Where do I find those vents that you are talking about?
Is it ok to use keihin jets with a dynajet needle? would i get the keihin jet from honda?
How does it run now? If you have a DJ kit, just use them. If you use the DJ needle, try putting the clip on the 3rd or 4th slot down from the top and test ride. The needle adjustment (clip) is your mid-range power. See the first post in this thread for the Keihin/Dynajet conversion chart. Best to know what's in the carb now. How does it run? Good low rpm pull, strong mid-range acceleration, strong top-end?
The filter vents can be found on ebay. Do a search for "Uni UFV-6". They are made by the same company that makes the Uni Filters in Fullerton, CA.
Here's another vendor that carries them: http://www.powersportsuperstore.com...5022&click=8321
For carb jets, etc. I would recommend JetsRUs.com. They are in Missouri and are really helpful.
Posted by: Shaun Martens
quote:
Originally posted by dave4881
How does it run now? If you have a DJ kit, just use them. If you use the DJ needle, try putting the clip on the 3rd or 4th slot down from the top and test ride. The needle adjustment (clip) is your mid-range power. See the first post in this thread for the Keihin/Dynajet conversion chart. Best to know what's in the carb now. How does it run? Good low rpm pull, strong mid-range acceleration, strong top-end?
The filter vents can be found on ebay. Do a search for "Uni UFV-6". They are made by the same company that makes the Uni Filters in Fullerton, CA.
Here's another vendor that carries them: http://www.powersportsuperstore.com...5022&click=8321
For carb jets, etc. I would recommend JetsRUs.com. They are in Missouri and are really helpful.
ok thanks. i'm redoing the topend now so i can't try it out and its been a few months since i tryed it. i just wanted to know what to start off with and go from there
Posted by: trailrider894
how would you guys jet a 2000 400ex
stock carb
open airbox with K&N/ w. outerwears
powerbomb header
e-series slip-on
crf timing chain\
sparks advanced timing key.
50-90 degrees
900ft.
Posted by: killer400ex
i have completely overhauled my ex, i put the hmf full sport exaust racing kit on it, i have the stage 2 hotcam in it, i bored it upp to a 426cc wiseco 11:1 piston, i had the head polished up, not ported, the air box lid is removed and i have a uni racing air filter, i am usally riding at 400 feet above sea level i was just wondering what the best jetting would be for the carb and it is a stock carburetor.
Posted by: hypersnyper6947
quote:
Originally posted by killer400ex
i have completely overhauled my ex, i put the hmf full sport exaust racing kit on it, i have the stage 2 hotcam in it, i bored it upp to a 426cc wiseco 11:1 piston, i had the head polished up, not ported, the air box lid is removed and i have a uni racing air filter, i am usally riding at 400 feet above sea level i was just wondering what the best jetting would be for the carb and it is a stock carburetor.
Well what jets are in it now, and how does it run
Posted by: FlewByU352
damn runnin today its pretty rich. Had a bog to it when stabbing off idle and you could see a little bit of black smoke. I just did a WOT high speed run again to see how the new colder plug looks. Top end higher RPM seems to run great but that bog when stabbing i'm thinking is because of the big main. Temperatures are rising its no longer 60 or 70 degrees when riding its 80's and soon to be 90's.
Posted by: MtnEX
quote:
Originally posted by FlewByU352
damn runnin today its pretty rich. Had a bog to it when stabbing off idle and you could see a little bit of black smoke. I just did a WOT high speed run again to see how the new colder plug looks. Top end higher RPM seems to run great but that bog when stabbing i'm thinking is because of the big main. Temperatures are rising its no longer 60 or 70 degrees when riding its 80's and soon to be 90's.
That don't sound right at all.
I didn't "back read"... so have you messed with the needle at all.
Sounds like you should be good on the main. Maybe you need to adjust your needle... or if you already have, and seem OK on everything except the bog...... well did you think to set the synchronization of the slide and butterfly?
If not, that will certainly cause a bog...
Posted by: FlewByU352
quote:
Originally posted by MtnEX
That don't sound right at all.
I didn't "back read"... so have you messed with the needle at all.
Sounds like you should be good on the main. Maybe you need to adjust your needle... or if you already have, and seem OK on everything except the bog...... well did you think to set the synchronization of the slide and butterfly?
If not, that will certainly cause a bog...
how do you adjust that? didnt know there was an adjustment for that. I have my jetting set at 42 pilot (unknown amount of fuel screw turns) 158 main and needle on the 3rd or middle slot. It used to run fine. I took the air filter off to see if that helped and it still bogs. I will check my plug tomorrow and then if it looks good or not for the main jet. then take the airboot completly off and see if it runs better with nothing restricting it. IMO 158 seems big for a slip on and filter at sea level in rather warm weather. Like I said it ran great before and now its a little sluggish with that bog most likely because the temperature is getting higher every day. If you rev the motor above idle a bit and stab it it goes. If your off idle it bogs now. Rich pilot circuit I assume? It idles fine though once its warm. Black smoke though when I was giving it some stabs and revving it up and down means its rich somewhere. I will figure it out. My quad doesnt seem to pull the front wheels up as good when I was doing he WOT test. When i 1st installed the key with a 155 main before my slide would go all the way up it would wheelie much harder and hover 3rd. Not its just a 1st and 2nd are up but not as extreme then 3rd no chance of liftoff.
Posted by: MtnEX
Well, the question is... have you or have you not messed with the needle since it was running well?
If not, it's not likely to be off, and there is no point explaining. If you have it is likely.
If you have not messed with the needle yet, check your plug on the needle.
It should be getting sooty somewhere in one of the circuits if it is rich. If it is not on any of them, you'll need to check the accelerator pump action, float level, etc...
Posted by: BEAVER.989
I could use a little jetting help if someone would be kind enough to help me...
I'm ready to purchase an exhaust system and a Uni filter for my quad and want to pick up the necessary jets at the same time. I will NOT be removing my airbox lid. The conditions I ride in will not allow it.
I'm thinking about picking up a 155 and 158 main jet along with a 42 pilot. Does this sound about right?
Posted by: FlewByU352
This is after the WOT run, the electrode and ceramic looked absolutley perfect, honestly it could not get any better unless you had a custom jet made thats in between maybe and tested on a dyno. The flat edge which i believe is the idle circuit? Correct me if i'm wrong there but that part was black. I screwed the fuel screw in a little and tested and there were pops after revving so then its lean. I now have it on 3 turns out no bogs at all and it runs great no popping but my quad still seems to still be hard to start. I have to pump the throttle a few times hit the button and keep the RPM up for a bit to get it warmed up to idle on its own. Camera didnt like close up shots at all on smaller objects which is a little disappointing because this plug really did look amazing.
Posted by: trailrider894
try going back and using either the macro setting on your camera or the one with the flower setting. that is what you want for close-ups cause for all i know those things that look like spark plugs could be hot dogs cause they to blurry so i can't see them.
Posted by: dave4881
quote:
Originally posted by BEAVER.989
I could use a little jetting help if someone would be kind enough to help me...
I'm ready to purchase an exhaust system and a Uni filter for my quad and want to pick up the necessary jets at the same time. I will NOT be removing my airbox lid. The conditions I ride in will not allow it.
I'm thinking about picking up a 155 and 158 main jet along with a 42 pilot. Does this sound about right?
What conditions do you ride in? Without opening up the airbox in some way, you're not going to get the change you are looking for. Try installing some Uni UFV-6 filter vents in the airbox lid which will allow it to breathe better. The 155 and 42 sound about right. Good luck.
Posted by: BEAVER.989
quote:
Originally posted by dave4881
What conditions do you ride in? Without opening up the airbox in some way, you're not going to get the change you are looking for. Try installing some Uni UFV-6 filter vents in the airbox lid which will allow it to breathe better. The 155 and 42 sound about right. Good luck.
The area I ride in gets pretty wet, so I'm a little concerned about taking on water. Any thoughts on that?
Posted by: dave4881
quote:
Originally posted by BEAVER.989
The area I ride in gets pretty wet, so I'm a little concerned about taking on water. Any thoughts on that?
Are you talking about rain coming down on your quad, or riding in deep water? If it's just rainfall or ridiing in wet mud, I wouldn't think that it would get to the top of the airbox. The airbox is also protected from above by the seat.
I can't be of much help with the "wet" conditions, since we don't get much of that out here. I ride mostly in the desert where it's dry. And, when we do get a downpour, it soaks in and makes riding even better. Good luck!
Posted by: Futurefelon400
07 400ex. HMF slip on. all stock. appx 600ft asl. 165main. 38 pilot (all kehin). coughing in midrange. HMF recomends a 165 main and no other adjustments.... Help
Posted by: Wheelie
A 165 is too rich for just a slip on.
Remove the airbox lid, install a 40 pilot and a 155-158 main.
Posted by: uspatriot
2000 400ex
stock main jet
42 pilot
white bros slip on
K&N filter lid still on
I installed he 42 pilot trying to get rid of the backfiring when letting off the throttle. This helped a little bit but it still backfires. What else can i do?
Posted by: Futurefelon400
thats what i thought. im gonna go with a 150-155 main. im runnin the stock filter is that ok with no lid? I ride in alot of dusty conditions, and have always liked to run with the lid on.
Posted by: dave4881
quote:
Originally posted by Wheelie
A 165 is too rich for just a slip on.
Remove the airbox lid, install a 40 pilot and a 155-158 main.
Not really. I run a K165 mainjet and have an HMF slip on. Quad runs fantastic!
Posted by: superelmer
quote:
Originally posted by dave4881
Not really. I run a K165 mainjet and have an HMF slip on. Quad runs fantastic!
any changes to your needle? i have a similar set up, will be jetting in a few days here...HMF came with a 165, but they say to bump up to a 170 without a lid/+filter, and move needle one position.
i'm in so cal too, mostly ride in Gorman...but here she is in glamis trim...
Posted by: FlewByU352
With a HMF slip on and K&N open airbox I am running a 158 Keihin Main. Jetting couldnt be better, a lot depends on location i'm only about 50-150ft above sealevel and the temperature was about 75° F when i checked the plug and it was great. Of course it will be getting about 100° F or so in the open area which would richen it up but it should still run fine and the little extra fuel will help cool it down some. I'm switching to an Iridium plug so i wont have any bogs or fouling problems. 165K Main seems a little high to me but I dont know all the specs where you are.
Posted by: riderssb250x
my buddys got an 01 400ex need jeting help
fmf powercore slip on, uni filter and no lid on the airbox any suggestions what would be good jeting or a good start?
Posted by: uspatriot
quote:
Originally posted by Wheelie
A 165 is too rich for just a slip on.
Remove the airbox lid, install a 40 pilot and a 155-158 main.
A 165 is perfectly fine, hes actually running to lean. Move the clip down a position.
Posted by: thebig450es
I just got a full big gun exhaust , k&N with outerwears, and planning on running without the lid, probably getting a sparks +6 key also, I run about 1000ft and between 40Fand90F. Its at the stock setting now, 148m,38p what should i buy? From what i read get a 42p and maybe 158 and 165m possibly 170mj. Thanks for the help
Posted by: DirtMonkey
Go to the JetsRUs website and it helps to explain everything and they have a jet kit for a 400 that is resonably priced
Posted by: Shaun Martens
will the 04 needle work on a 05 carb
Posted by: beags86
finally jetted my 400 today. here's what i got
fmf Titanium 4 slip on pipe
k&n air filter
open air box
jetted it with dynojet kit
138 dynojet main
(138=150)
dynojet needle-third clip
40 pliot
three and half turns out on the air fuel screw.
i used the 138 main because i have a dial-a-jet going on it as well
i didn't put it on because i wanted to see how it ran with the bigger main and pliot.
went for a ride and i could really tell a difference it is faster...pulls the wheels better in third. but doesn't seam to as well in first.
still backfires a little when you let off so i think with the dial-a-jet it should be spot on!!
Posted by: dave4881
quote:
Originally posted by beags86
finally jetted my 400 today. here's what i got
fmf Titanium 4 slip on pipe
k&n air filter
open air box
jetted it with dynojet kit
138 dynojet main
(138=150)
dynojet needle-third clip
40 pliot
three and half turns out on the air fuel screw.
i used the 138 main because i have a dial-a-jet going on it as well
i didn't put it on because i wanted to see how it ran with the bigger main and pliot.
went for a ride and i could really tell a difference it is faster...pulls the wheels better in third. but doesn't seam to as well in first.
still backfires a little when you let off so i think with the dial-a-jet it should be spot on!!
Your 138 dj main isn't much of a change from stock. I would recommend a 160K or equivalent. Your pilot screw is turned way out (3 1/2) which indicates you could easily go to a 42 pilot, then you'd only be about 2 turns out.
With a 148 (keihin) mainjet being stock, a lot of guys on here are making small increases in jetting by choosing 150's or 155's. For a real noticeable difference in power, I recommend, at a minimum, a 158 or 160 (keihin). But only if you have opened up the exhaust and the airbox. Then, you'll really have a "flier" and your engine will run cooler too. Remember, excess heat kills parts.
Posted by: beags86
yeah i know its not much of a change but the dial-a-jet richins all the circuits so the main will be effectively bigger. along with the pliot
Posted by: thebig450es
Just went out riding and thanks for all the help it is great
I used a 42p, 172m, and everything else is stock settings
Plus it runs great with or with out the air box lid.
Posted by: monkeyballs
quote:
Originally posted by zrpilot
Actually the suggestions given were not that far off. A 5 point main adjustment, IMO, would be hardly noticeable by the average rider. A pro like Ballance, yeah maybe, but not me on my 400EX....
If the shop did your jetting on a dyno, then it will be probably dialed in great.
Here is a dyno run done on my quad that shows a 6 point main change and you will see VERY LITTLE power difference. However notice the AF ratio did change.
First of all 37 hp wow! ****.. Im kinda suprised. Im now wondering how much hp my bike has. Honda 416ex, full system yosh pipe, k&n air filter, stg 1 hot cam, cleaned up factory port job and polished exhaust ports. Running no air box lid.
Was your dyno tested to the engine or wheels? And what all do you have on your bike?
Posted by: monkeyballs
quote:
Originally posted by monkeyballs
First of all 37 hp wow! Crap.. Im kinda suprised. Im now wondering how much hp my bike has. Honda 416ex, full system yosh pipe, k&n air filter, stg 1 hot cam, cleaned up factory port job and polished exhaust ports. Running no air box lid.
Was your dyno tested to the engine or wheels? And what all do you have on your bike?
Posted by: beags86
quote:
Originally posted by dave4881
Your 138 dj main isn't much of a change from stock. I would recommend a 160K or equivalent. Your pilot screw is turned way out (3 1/2) which indicates you could easily go to a 42 pilot, then you'd only be about 2 turns out.
With a 148 (keihin) mainjet being stock, a lot of guys on here are making small increases in jetting by choosing 150's or 155's. For a real noticeable difference in power, I recommend, at a minimum, a 158 or 160 (keihin). But only if you have opened up the exhaust and the airbox. Then, you'll really have a "flier" and your engine will run cooler too. Remember, excess heat kills parts.
bumped up to a 160 main after work today..didn't ride it thou.
the a/f screw is still turned out 3 and 1/2 did this because the dynojet kit recommends this setting.. i'll play with later when i ride.
Posted by: dabrowat
I have a 400ex with K&N filter, White Bros exhaust. I ride below 1000ft. How should my carb be tuned if the spark plug was black?
Posted by: beags86
quote:
Originally posted by dabrowat
I have a 400ex with K&N filter, White Bros exhaust. I ride below 1000ft. How should my carb be tuned if the spark plug was black?
open air box? stock jetting?
clean your plug with a wire wheel stick it back in and ride a bit. then see if it's still black after a ride.
Posted by: quadracer585
I'm running a stock carb with an hmf slip on .40 over 89mm 11:1 compression and a stage 2 hotcam at about 500ft. any suggestions on jetting it??
Posted by: quadracer585
oh yeah..no air box lid
Posted by: dave4881
quote:
Originally posted by beags86
bumped up to a 160 main after work today..didn't ride it thou.
the a/f screw is still turned out 3 and 1/2 did this because the dynojet kit recommends this setting.. i'll play with later when i ride.
Using an arbitrary 3 1/2 turns out is just pure guesswork.
Adjusting the a/f screw is a simple procedure.
1) Warm up the engine.
2) With the engine idling and choke off,
turn the a/f screw in (clockwise) until rpm's increase slightly.
3) Then, turn the a/f screw back out (counter-clockwise) about 1/4 to 1/2 turn.
This sets the mixture on the slightly rich side of the best a/f ratio. Engine will run better and a little cooler. A #42 pilot is highly recommended.
Posted by: Tofu.Man
Hey fellas. Mabey you guys can clear some hazyness up for me. I have read a lot about tuning carbs through this forum, JetsRUs and even more. The one thing I don't see a whole lot about is the adjustment of the mid-range A/F. I understand the needle is what controls the mid-range but how do you determine when you need to drop down a notch on the needle? Is it just a crap shoot. There has got to be some method other than a Wideband and a dyno.
Posted by: MtnEX
quote:
Originally posted by Tofu.Man
Hey fellas. Mabey you guys can clear some hazyness up for me. I have read a lot about tuning carbs through this forum, JetsRUs and even more. The one thing I don't see a whole lot about is the adjustment of the mid-range A/F. I understand the needle is what controls the mid-range but how do you determine when you need to drop down a notch on the needle? Is it just a crap shoot. There has got to be some method other than a Wideband and a dyno.
You're on the needle from 1/4 to 3/4 throttle. So this is the easier one to check. Put in a fresh plug gapped correctly, drive it around staying in that throttle range, then check the plug.
If the plug is black, your needle clip is too low, raising the needle too high and letting too much fuel through from the main. If your plug looks lean, either the needle clip is too high or the main is too small.
If you know your pilot and main jet are right, it's pretty easy to figure out which way to go, by the look of the plug and the way the bike responds to throttle and running in the mid-range.
Remember though that when messing with the needle adjustment, you can mess up the carb timing... (slide, butterfly, accelerator pump squirt) ...which can have you end up chasing your tail.
It's a stupid design in a way because you have to loosen the set screw on the link arm... slip the link arm shaft out, in order to move the link arm and slide up out of the carb to get to the needle...
So there is always a chance you don't set the set screw in the same rotational spot on the link arm shaft.
If so, the timing of when the slide moves up and down is effected. If you have seen how close together the needle clip slots are, you can understand how easily this could affect things... but not only that, it can also cause the slide to be in the way of the accelerator pump's stream.
Posted by: beags86
quote:
Originally posted by dave4881
Using an arbitrary 3 1/2 turns out is just pure guesswork.
Adjusting the a/f screw is a simple procedure.
1) Warm up the engine.
2) With the engine idling and choke off,
turn the a/f screw in (clockwise) until rpm's increase slightly.
3) Then, turn the a/f screw back out (counter-clockwise) about 1/4 to 1/2 turn.
This sets the mixture on the slightly rich side of the best a/f ratio. Engine will run better and a little cooler. A #42 pilot is highly recommended.
i am well aware of how to do that. but what tells you that this is the correct setting vs what dynojet claims. i won't be useing a 42 pilot because i will be useing a dial-a-jet as well with this combo. that will richin the the carb needle. pilot. and main.. right now i am working mostly with the main. i intend to get it spot on and then back it off a bit for the dial-a-jet
Posted by: Tofu.Man
quote:
Originally posted by MtnEX
You're on the needle from 1/4 to 3/4 throttle. So this is the easier one to check. Put in a fresh plug gapped correctly, drive it around staying in that throttle range, then check the plug.
If the plug is black, your needle clip is too low, raising the needle too high and letting too much fuel through from the main. If your plug looks lean, either the needle clip is too high or the main is too small.
If you know your pilot and main jet are right, it's pretty easy to figure out which way to go, by the look of the plug and the way the bike responds to throttle and running in the mid-range.
Remember though that when messing with the needle adjustment, you can mess up the carb timing... (slide, butterfly, accelerator pump squirt) ...which can have you end up chasing your tail.
It's a stupid design in a way because you have to loosen the set screw on the link arm... slip the link arm shaft out, in order to move the link arm and slide up out of the carb to get to the needle...
So there is always a chance you don't set the set screw in the same rotational spot on the link arm shaft.
If so, the timing of when the slide moves up and down is effected. If you have seen how close together the needle clip slots are, you can understand how easily this could affect things... but not only that, it can also cause the slide to be in the way of the accelerator pump's stream.
So in essence when you set the pilot and the main jets you shoud be VERY close to correct on the 1/4 to 3/4 throttle A/F ratio. If it is running a little lean on the 1/4 to 3/4 throttle range go up on the main and run a little fat on top and forget about messing with the clip postion? Because of what seems to be somthing that could potentialy cause a world of problems.
Posted by: FlewByU352
get your pilot right 1st of all so you can atleast have it idling. then your main so you know your topend will be set, then adjust the needle. if the main is right then you can get the needle right, but the needle right doesnt mean the main is right thats why you do the main 1st. needle is kind of like the fuel screw fine tuning.
Posted by: BossHogg420
so how exactly do u access the needle and can u do this with the carb on the quad?
Posted by: MtnEX
quote:
Originally posted by Tofu.Man
So in essence when you set the pilot and the main jets you shoud be VERY close to correct on the 1/4 to 3/4 throttle A/F ratio. If it is running a little lean on the 1/4 to 3/4 throttle range go up on the main and run a little fat on top and forget about messing with the clip postion? Because of what seems to be somthing that could potentialy cause a world of problems.
In theory yes...
In reality maybe not...
Step up to a 40 or 42 keihin pilot jet, just to make it start better.
Then tune your main in with keihin jets.
Then see how it does on the needle.
Obviously you are going to spend a lot of time running on the needle so it needs to be right.
The needle's function is to meter the fuel flow down coming from the main jet so the air fuel mixture is right as the slide rises and the butterfly opens.
It's tapered down to a point...
This shape gives it a smooth decreasing effect on metering as it raises up out of the holder orifice. The more it raises as you give it throttle, the less it restricts.
It can be adjusted down farther in the needle holder to have a more restrictive effect as it rises... or adjusted up farther to have a less restrictive effect.
It's like inserting a tapered stick into the bottom of a funnel.
Now in theory you shouldn't have to touch it... but in reality, you may need to. You may see the need on the plug or feel the need in the throttle response.
Going to a larger main can have a richening effect on the rest of the circuits.
If the needle setting is too rich, it will richen the low end, making it a little richer at idle, and richer in the midrange. It may flood easier on starts, and it will be lazy, sluggish and rich acting in the midrange... rich smelling, smoky and the plug will be black or wet after a run on the needle.
In other words, you'll know, and when you make a change of one clip position you'll be able to feel it.
Posted by: MtnEX
quote:
Originally posted by BossHogg420
so how exactly do u access the needle and can u do this with the carb on the quad?
You have to take the top cover off the carb to see the slide/needle area.
You have to loosen the screw on the link arm shaft and take the side cover off to slide the shaft out of the link arm to be able to lift the slide out.
Then you have to take the link arm shaft off the slide to get to the needle itself.
The answer is YES, you can access it while the carb is still on the machine, but to me, it is more trouble than it is worth. It may not be to some others, but to me, it makes it easier to work on if I just remove it.
Posted by: Tofu.Man
MtnEX thanks for all the help. You have really shed some light on needle tuning. In combo with reading the Clymer manual and the info you have given me I believe I can tackle the needle no prob.
Posted by: Honda#4
Just make sure you dont strip the two little screws inside the throttle body that hold the needle in.
Posted by: Tofu.Man
quote:
Originally posted by Honda#4
Just make sure you dont strip the two little screws inside the throttle body that hold the needle in.
Well Noted. Thanks!
Posted by: dabrowat
I have K&N filter open airbox, white bros exhaust. I ride at 600ft. How should the carb be set up if the spark plug was black after a ride?
Posted by: beags86
quote:
Originally posted by dabrowat
I have K&N filter open airbox, white bros exhaust. I ride at 600ft. How should the carb be set up if the spark plug was black after a ride?
i'm not much of a carb tuning guru but i would recommend turning your air/fuel screw in all the way and then turning it back about 2 turns, then see if it's still rich, is your carb jetted?, if it's not with those mods it should be running a bit lean with the stock carb settings.
Posted by: KrackerG
i'm new to jetting, i am getting a whole set of jets (152-180) for my 440ex, i am thinking 158-165 main jet along with a 42 pilot. does this sound about right? where should i be shooting for?
440ex
stock 400ex carb
full exhaust
K&N filter
no airbox lid / outerwears
~1000 ft. trails mid atlantic
Posted by: rob_990
start rich then try it full throttle then just keep going down couple sizes each time until the stumble at full throttle is gone.
Posted by: beags86
UPDATE: jetted with a keihin 45 pliot, 165 main, haven't messed withe a/f screw yet, still at 3 1/2 turns out, and still have the dynojet needle on the third clip... anyway the thing runs like a rapped ape now, it wheelies on comand in third gear, before i had to pull on the bars and now it will wheelstand all day long in third all by itself!!!
very happy with this setup and i don't think i will be changing it anytime soon.
Posted by: Tofu.Man
400ex with the followin Mods,
Curtis Sparks X6 exhaust
Curtis Sparks advance key.
Im at 390ft elevation.
My jetting is a 42 pilot and a 165 main, stock needle setting and 2 turns out on the fuel screw. All keihin jets BTW.
I dont know anyone else with similar mods. I would just like to know where they are at and what jets they are using.
Posted by: BEAVER.989
Has anyone noticed the need for different jetting with identical mods to a 99-04 vs. the 05-up? It is my understanding they have different carbs.
Just thought I'd point out the potential for differences to anyone who's using this thread as a guide.
Posted by: MtnEX
OK... time for me to ask for some feedback...
I'm doing a carb rebuild kit since it needs one... and while I'm at it, I want to perfect my livable but imperfect jetting...
I live at 1250 ft elevation and usually stay under 3000 ft.
I have a Yoshimura full exhaust, and a K&N in the airbox with the lid ON.
What would be your jetting recommendation?
The guy who did my work only changed the main jet, and he put in an RD precision part... that I want to get out of there.
I don't think it is way off, but the circuits can't be properly tuned together.
I think it's a tad lean on the pilot and a tad rich on the main. But it does not run bad or pop, backfire, etc...
The RD Precision main jet is a 155.
The stock pilot is of course a 38.
Should I get BOTH a 40 and a 42 pilot?
What about the main jet? I don't know how close that RD jet is to genuine part size.
I was going to just pick up a few jets, rather than a jet kit.
I'm also considering switching from the K&N to a foam filter like the Uni, etc...
Can I get some suggestions... or should I pay $30 for the following set of main jets?........
152, 155, 158, 160, 162, 165, 170, 175, 180
Posted by: Wheelie
I'd recommend a 38 or 40 pilot and a 152 main.
Posted by: MtnEX
quote:
Originally posted by Wheelie
I'd recommend a 38 or 40 pilot and a 152 main.
Is that based off what I have and the elevation?
Or did you arrive there about the same way I did?
I was thinking up a size to 40 on the pilot to get it a little richer... but everyone else runs a 42... So I was second guessing.
Then I figured 152 main if the 155 seems too rich... provided the RD 155 is the same size as OEM.
I'm going to call the local Honda dealer and if they don't want their usual retarded prices for jets also... I might just get those there one at a time.
Posted by: Goob
What should I run in mine I have a 09400x 42 pilot choke removed k&n filter lid on 500 ft above sea level it's Seems to run it's best at 152 main
Posted by: turbotexas
This is what I found in the 400ex I bought!
quote:
Originally posted by leasureryan
IMO........K&N filters are the absolute WORST filter that you can use for dirt applications. I have seen so many quads and dirt bikes come through the service dept at work, with BOULDERS in the carb and intakes. Those things were made for car and street bike applications....not dirt. They just figured that they would expand thier prodution, and make a little extra cash....and hell.....they already had a popular well known name in performance filters....right???....they must be great.....right????......WRONG!!!
Outerwares or not.......K&N=J&U&N&K
Posted by: turbotexas
quote:
Originally posted by turbotexas
This is what I found in the 400ex I bought!
and the previous owner wondered why it smoked so bad???
Posted by: turbotexas
quote:
Originally posted by turbotexas
and the previous owner wondered why it smoked so bad???
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