[YFZ450 Jetting .] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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YFZ450 Jetting .
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Posted by: Quad18star

I'm wondering if a Moderator would be able to sticky something liek this for us . How about we set up what everyone is running for their jetting in the YFZ450 . I know it's a pain in the butt to have to search all over to find the answers . It's just a suggestion and I'm sure it would help a lot of people out , as well as stop a lot of threads about jetting info .... it could be like a one stop shop for jetting .

Anyways here's my setup ...

Full Curtis Sparks stainless steel exhaust with Sparks Racing filter and adapter (no airbox lid) , along with Sparks racing jet kit .

Approx . 1000 feet above sea level
Temperature between 65 - 80 F with an average of 72F

45 Pilot jet
178 Main jet ( cuz it's cold right now)
NCVQ needle with clip on middle setting
2 1/2 turns out on the fuel screw

These settings seems to be fine for now ... but has a little bit of popping on de-accel . Could be caused by the cold temps ??

Posted by: Fred55

GYTR Aluminum Slip-on
168 M
45 P
4th clip on NVCQ needle
2 turns out on fuel screw
GYTR Foam filter, no air box lid

Posted by: Splatter Matter

DR.D pipe

172 main
45 pilot
4th nvcq needle
2 1/4 turns fuel screw

K&N air filter no lid

Posted by: jlhughes750

NCVQ dirtbike needle clip on the middle

172 main

45 pilot

94 octane sunoco fuel or VP 10?

Sparks full pipe

Sparks foam filter and Sparks ring
also ran K&N with pro design intake ring with same jetting.

I'm in eastern Pa. not positive of the elevation??

Posted by: TheWolf

what about the fuel you are using? I would assume that no mention would be pump gas. You should mention what fuel you use if it is race gas or oxigenated gas.

Also if you know your altitude, mention that.

Thanks

Posted by: Fred55

I changed mine lol, the other one kept fouling plugs?

now im at a
165m
42pilot (stock)
NVCQ 3th clip
Fuel screw 3 turns out

Posted by: sampleez

i finally got my pipe in, and my jetting felt pretty good, but it was about 30 degrees, so i'll have to lean it up a little when it warms up. i have a Dr. D slip-on, the cam mod, and the air box lid off with the stock filter set-up. i run 93 gas, and my elevation is about 750-1500. my jetting is:

172 main
48 pilot
stock needle in 5th position
fuel screw about 2.5 turns out

Posted by: Quad18star

Thanks to everyone who has responded so far ..... but come on you other guys ... post up . Help fellow riders out ... I know there are a LOT more of you guys out there with pipes .... especially when this thread has gotten over 300 views .

Posted by: cdalexct

178 main
45 pilot
ncvq on 5th
2 turns on fuel screw
94 sunoco fuel

Posted by: Quad18star

quote:
Originally posted by cdalexct
178 main
45 pilot
ncvq on 5th
2 turns on fuel screw
94 sunoco fuel

Stock pipe ?? airbox lid on or off? Temps ?? Elevation ??

Posted by: cdalexct

quote:
Originally posted by Quad18star
Stock pipe ?? airbox lid on or off? Temps ?? Elevation ??

HMF full system
airbox lid off with prodesign proflow kit(foam)
airbox lid outwear
35 degrees out runs good
Live in PA dont know Elevation

Posted by: Quad18star

quote:
Originally posted by cdalexct
HMF full system
airbox lid off with prodesign proflow kit(foam)
airbox lid outwear
35 degrees out runs good
Live in PA dont know Elevation

Perfect ... thanks for posting more info .... I think the average Elevation in PA is the same as I have ... anywhere from 700ft to 1300 ft .

Posted by: Bill Fuller

HMF full system with Quiet core insert
UM aluminium air box w/250R Uni foam filter,lid on
North Tenn 500ft elvation
Fuel screw at 2 turns out
165main
45 pilot
NCVQ needle on 3rd clip
94 Ultimate

Posted by: Fred55

Thats exactly what im running except a 42 pilot, what temp are you at?

Posted by: Bill Fuller

Wintertemps range from 20 to 50 degrees.I was running a 162 until I put on the UM airbox/250R Uni.

Posted by: Fred55

Your like the only other person that ive seen with a 165 besides me...everybody says to try 168, and i tried that and i was WAY too rich...weird huh

Posted by: Bill Fuller

I followed HMF instructions and my quad ran like CRAP.I started with the 175 main and the 45 pilot.I went to the NCVQ needle right from the start.It took about 2 months to get it to where I am now,believe me I tried all the combos.I finally ordered jets from 160 to 180(Carb parts wharehouse

)When I had the 170 in it ran like there was water in the gas.When I kept messing around,thought I was there with the 165 main.After going to H/M last year I realized that weasn't right either.I started to think there was a deeper problem(rectifier/electric).But I finally got the 162 in and BINGO there it was.

Posted by: Fred55

yeah it seems that you and i are leaner that everybody else, which is weird too...with full exhausts and filters, i wonder what is causing them to go up so high as 172 and even 180 as hmf suggests

Posted by: SRH

what do you guys recommend for this setup as a good starting point

lid on
dr d slip on w/ fmf powerbomb "sx" header
cam mod
uni air filter
1200 ft above sea level
60-80 degrees
pump gas 93

from what i read about what alot of guys run i was thinking a good starting point would be

168 or 170 main ( what do you guys think)
45 pilot
nvcq needle 4th clip
air screw 2.5 turns out

anyone have a better idea for a good starting point? my quad felt sluggish at times last year and had a slight bottom end hesitation at times with the dyno junk kit and i really wanna solve that

Posted by: Fred55

I have a 165 main
42 pilot(stock)
3rd clip on NVCQ clip
3 turns out on fuel screw

Im at about 1000-1100 ft
and at the moment temps are around 40, i raced a 1 hour harescramble yesterday and it ran great.

Posted by: sampleez

hey srh
main sounds pretty good, pilot will prolly need to be a 48, but 45 might work if it's pretty warm. everything else looks pretty close too

i think upping the pilot is supposed to help the bog

and did you get the header and pipe at the same time, or did you have the stock header on for a while. i was wondering how much that header you have helps. i am really impressed with the dr.d so far tho.

Posted by: ESrider

168 main
45 pilot
airbox lid removed
stock pipe with insert removed
350 feet above sea level
93 octane

Posted by: Quad18star

SRH .... that sounds like a good starting point !!!

Posted by: AshYFZ450

Altitude: Sea Level (Glamis, Gordans, Ogilby)
Temp: Hot (days) Cold (nights) 50f-80f
Cam Mod Yes
Intake: K&N (stock manifold with airbox removed completely)
Exhaust: GYTR slip-on
Main: 172
Pilot: 48
Needle: NCVQ 3rd clip
Fuel Screw: ZipTY 2 1/2 turns

Posted by: tgyolai

i am new to this i am running no lid with pro design air filter system just got sparks header and silencer main is 165 pilot is 42 3rd groove from topon needle this was gytr jet kit i dont know where the fuel screw is so dont know where that is set

Posted by: Quad18star

quote:
Originally posted by tgyolai
i am new to this i am running no lid with pro design air filter system just got sparks header and silencer main is 165 pilot is 42 3rd groove from topon needle this was gytr jet kit i dont know where the fuel screw is so dont know where that is set

I'd run a bit higher main jet ... Sparks recommends a 175 I believe . Also bump that pilot up to atleast a 45 . The fuel screw is underneath the carb and is ressed in ... you'll need a long skinny flat head screw driver to get at it . 2 1/2 turns is what is recommended with Sparks .

Posted by: tgyolai

thanks quad18star

Posted by: SRH

quote:
Originally posted by sampleez
hey srh
main sounds pretty good, pilot will prolly need to be a 48, but 45 might work if it's pretty warm. everything else looks pretty close too

i think upping the pilot is supposed to help the bog

and did you get the header and pipe at the same time, or did you have the stock header on for a while. i was wondering how much that header you have helps. i am really impressed with the dr.d so far tho.

yeah i like the dr d, i havent run with the powerbomb yet , im actually waiting for it to come in, should be next week or so

Posted by: aci clay

168 main 45 pilot, stock needle,fuel screw 3 turns out, lid off, pro design foam filter,3000 ft. elevation so cal hi desert

Posted by: dudleydoright15

I am running a 05, yfz450 with a white brothers E-2 full exhaust with air box lid off and pro flow filter.

175 main
42 pilot
needle out of a yz450 on needle clip position 4
1 1/2 turns out

elevation is between sea level and 500ft.

works great but a little bit of popping when I let off of the gas.

Posted by: 450Rcarbonpro

washington evlevation 800 to 1000 ft.
degrees 50 to 80

Posted by: Bill Fuller

I tried everything up to a 180 main.I tried the NCVQ needle on clip positions from 2 to 5 clips.I never tried anything above a 45 pilot.My bike would run like shiat from 1/2 throttle up until I started moving to what I was being told was lean.Once I started coming down she ran better and better until I finally came up with my settings=45 pilot,3rd clip on NCVQ needle and a 162 main.I have a HMF full system with Quiet Core insert,airbox with lid on.(No engine mods)Runs GREAT!!

Posted by: Quad18star

What would cause a flame to shoot out of the exhaust ???

I'm running a 175 main , 45 pilot, 2 1/2 turns on the fuel screw .... full sparks system with foam filter and adapter , no air box lid .

The temps are hot right now ... like 80+ degrees and Im at about 1000 feet.

Posted by: drgnerth

When does it do it? Wot, idle, all the time. You look to be rich on the main.

Posted by: drgnerth

By the way.
170 main 45 pilot middle clip on NCVQ 1 3/4 on air/fuel mixture 800 ft above sea level.

Ron Woods intake, no air box, K&N w/ outerwear, Hot Cams, WR crank, rod, piston, full HMF sport.

Posted by: Quad18star

My dad just took my quad out yesturday , and he said it was really missing in the higher RPMs . I didn't really get to see him or hear him on it , so I can't tell if it was the motor bouncing off the rev limited ( I have stock gearing with 18" rear tires) or if it was my jetting .

What would you guys recommend for jetting of an 04 with full system Sparks pipe and filter setup ?? The temps are in and around the freezing mark right now and the last time I checked my plug it was really rich , but that was with hot temps .

Posted by: JDiablo

WHat will you guys reccomend for this setup?
Rossier full exhaust
CFM open airbox with UNI filter
Cam mod
elevation 700-1000
Temp 25-45ish
Can anyone give me a good place to start at thanks

Posted by: Quad18star

When all else fails for jetting , just forget to install the main jet and let that sucker run rich .

Posted by: E.POWERSPORTS

Can you post the stock jetting on a '04?

Posted by: onall4rs

i have a full yoshi system, air box lid off,180 main 42 pilot,air screw rounded off

and its not turning. engine a pig to start
hot or cold
help

Posted by: xcnick38

full system yoshimura TRC...

158 main
50 piolet
new needle i think 3rd clip

air box lid is on and im also in PA it runs great...

Posted by: onall4rs

i drilled the air screw out today and have a new comeing on friday
so hope to heve the problem solved

Posted by: drue4mpg

06' yfz450

Bill Ballence GYT-R titanuim head and pipe
High flow No Box lid
165 main jet
45 pilot
GYT-R needle Clip 3
2 full turns
seattle 200'
it seems to be dialed in no bog or lag through out the range
made a huge difference on the 3rd groove and taking it back from 2 1/2 to only two turns
its so fast now my girl wont get on it anymore .........PERFECT

Posted by: drue4mpg

GYT-R Titainum full
Pro intake LID OFF
(Bill Balence Kit)
165
45
GYT-R 3rd clip
2 1/2 turns

Seattle WA,
I'm around 400 feet
70 degrees

Posted by: yfzcrazy

I need help i just got the velocity intake and purchased the FMF titanium4 full exhaust and iam not sure what jets to use or even how to figure it out. i was reading your colum and noticed a lot of stuff i dont understand like the fuel screw turns or the size of the jets or temps and elevation. Well i live in san diego so temps are usaully between 50-80 at sea level but i love to go to the desert but i am unsure of the elevation. any help will be great thanks.

Posted by: jcline

165 Main Jet
Pilot, Fuel Screw, and Needle Position Stock
Stock Pipe w/ Baffle Removed
Stock Filter w/ Air Box Lid On
93 Octane Pump Gas

Posted by: BrianEX

I just bought a Big Gun Race Series complete exhaust and will need to rejet. Any recommendations of where to start would help. Only other mods are: no airbox lid and a K&N filter.

Rockford, IL Elevation is around 800 feet.
Temp: 65 degrees

Thanks.

Posted by: husa

Hello,

I�m new here and have registered for one question.
(I have no quad, but a keihin carburretor from YFZ450,year 2004)

I installed it in my husaberg enduro.

I�m surching for a good jetting, and have spend a lot of time in the web.
(It�s quite plain to me, that your jettings must not be the best for my engine (501ccm, longstroke), I will not just copy this )

The stock needle was a NDS-R

The most people here changed to NCV-Q

looking in the keihin.us needle chart
http://www.keihin-us.com/am/_media/..._jetneedles.pdf

the needles are termed OC-XXX

(OB is possible too, I know the difference to OC)

Is a NCVQ in full term OB-NCV???
This is improtand for me to get information about the diameter and so on.
And when this is right, was does the smaller fourth letter "R" mean?
for example Kawasaki has a NCVR needle in the FCR40 (KX450F Motocross...)

thanks in advance!

Posted by: 06 YFZ FATBOY 4

06 YFZ 450: 172 MAIN, 42 PILOT,NCVQ 4TH, K&N NO LID, FATBOY 4 FULL SYSTEM, EXHAUST CAM MOD, 2.5 TURNS ON FUEL SCREW, ELEVATION 2000'-2300', 17-30 CELCIUS=APPROX 65F? IAM HAVING PROBLEMS WITH TOP END WOT, I AM GOING TO TRY 45 PILOT & 175 MAIN TODAY IF IT STOPS SNOWING YAH THATS RIGHT SNOWING

ON APRIL 19. SHEEET I SHOULD BE RIPPING UP THE SAND WITH MY BOYS!!!!!!!. IF ANYONE HAS CLOSE TO THIS SET UP ON THE 06 WITH NO TROUBLE @ 3/4 TO WOT PLEASE POST IT.

Posted by: Xater

what do you guys think the jetting should be with baffle out and lid removed?

Posted by: sdbrown12388

'06 with full gyt-r exhaust, gyt-r air filter
165 main
42 pilot
3rd clip
2 and a half turns

Posted by: bradley300

i noticed no one is mentioning the leak jet??? are you guys having problems with the stumble off idle when you stab the throttle?

louisville, KY
stock filter, no lid
HMF slip on

170 main
NDSR needle #3 down
45 pilot
2 out on the feul screw
30 leak jet
raised the idle just a hair from what would sound normal. it doesnt scream, but its a little more than a slow chug like you would hear on a 400ex

very slight stumble off the bottom when stabbing the throttle from nothing to full, but a 25 leak jet should fix it.

Posted by: 06 YFZ FATBOY 4

BRADLY 300: I DONT HAVE A PROBLEM WITH A STUMBLE WHEN I STAB THE THROTTLE, IT WAS JUST @ 3/4 TO WOT, IT SEEMED TO HAVE MORE TOP END @ 3/4 THROTTLE THEN IT DID @ WOT. I PUT A 175 MAIN AND PLAYED WITH FUEL SCREW, THIS CLEANED UP MY PROBLEM @ WOT. QUESTION- IF I PUT A 45 PILOT IN WOULD I NEED TO PUT A 178 MAIN JET FOR MORE FUEL TO MATCH UP WITH THE MORE AIR? I THINK SO BUT NOT TO SURE. MORE FUEL & MORE AIR = MORE POWER?

Posted by: bradley300

i doubt it, but you'll only know once you ride it

Posted by: 06 YFZ FATBOY 4

Thanks for the replie, the more you work on them the more you learn. have a great & safe summer!!!!

Posted by: 06 YFZ FATBOY 4

BRADLEY 300. I got it figured out 175 main, 42 pilot, 2 turns on fuel screw, ncvq 4th, k&n no lid, cam mod, fatboy 4 full system, 15 tooth sprocket, elevation 2000'- 2500' approx. works great no hesitation off bottom end, no bobble at 3/4 to wot

thanks for everyones help on this sticky!!!!this thing hauls ***** now!!!

Posted by: yfzrider310

for the stock exaust with the baffle removed do i have to change the jetting or should i just leave it stock

Posted by: jcline

I changed the main jet to a 160 and took the air box lid off. Runs great!

Posted by: 06 YFZ FATBOY 4

quote:
Originally posted by yfzrider310
for the stock exaust with the baffle removed do i have to change the jetting or should i just leave it stock

The answer is yes you should change your jetting, take your air box lid off and see how it runs.

Posted by: yfzrider310

does taking the airbox lid off make that big of a difference??

Posted by: ohsobad_chevy

Northern Oklahoma: Approx. 700 ft.

2007 YFZ 450 SE
Curtis Sparks X6 pipe
UNI air filter w/o airbox lid
Air temp around 74 degrees

165 main
45 pilot
4th clip on NCVQ needle
All the way in and 2.5 out on the screw

Posted by: jcline

Taking the air box lid off was a must after I changed the main jet. It did'nt run right otherwise. The combination of the changes gave me noticeably more on the low end.

Posted by: walshyfz86

Ported head
web +5 cams
WR crank
CP 13:1 piston
Stock airfilter. half a airbox. back is cut off.And screen removed
C12 fuel
Sparks bigcore exhaust

In nj not sure elevation.

180 main
48 pilot
Stock needle 5th clip down
2 1/2 turns out

Professionally dynoed where these were the best settings.

Posted by: 06 YFZ FATBOY 4

I just bought a 07 se, elevation 2000- 3000, temp +10 deg, main 175, pilot 42, no lid, cam mod!!, drilled out exhaust, ncvq 4th clip from bottom, 2 1/4 turn on fuel screw. I still have the 06. blown motor. any body with a 04- 05 -06 do the oil mod NOW!!! or your looking at lots of $$$$ for parts. crank seized not enough oil to the crank.

Posted by: sylvan_srt4

2004 yfz
elevation : 2800 feet
mods : alba full pipe, velocity air filter w/o air lid
main 170
pilot 45
stock needle 5th clip
fuel screw 2.5 turns out

Posted by: X-Factor

DASA fullsystem
Complete racing Head
ProDesign with lid off (Foam)
DynoJet kit - 142 main & 48 pilot
Elevation 500ft
Average Temp - 77

Posted by: BrettOaktree

HMF sport series slipon and K&N air filter with the airbox lid on

928FT elevation

165 main
48 pilot
1 turn out on the fuel screw
3rd needle clip
93 valero fuel

runs really good power throught the entire rpm range and doesnt backfire

Posted by: moisey_4

Im in Seattle Wa so my guess is that its sea level-1000ft.

Ron woods full exhaust
ron woods intake system with k&n no airbox
Pump gas

jetting:
175 main
48 pilot
5 postition on needle (from top)
1 1/2 turns out on fuel screw

Seems rich but rips, and never had to chang a spark plug yet.

Posted by: 06billballance

new here but want to put my 2 cents in,06 yfz 450 bill ballance,white bros slip on,175 main,48 pilot,stock needle,adjustable mixture screw,in omaha ne.this thing runs great.neck and neck with a buddies ktm 525

Posted by: toomey450

i have a 06 yfz 450 with the toomey slip on, and k&n air filter no lid. the slip on came with a 175 main jet but it just wasnt right. when you stab the throttle it chokes the quad out. and my choke switch doesnt work, when you pull it out it kills the bike.

i just bought a gytr jet kit for it but im not sure witch jets to put in and what to set the needle as... any suggestions?

Posted by: ohsobad_chevy

Not for sure how the numbers are on the GYTR jets. Is the 175 main a Keihin jet or a GYTR? It should have a little K with a star if its a keihin.

Posted by: toomey450

not sure what kind of main jet it is. they just sent it to me with the toomey slip on pipe.

Posted by: DMC-4OOEX

quote:
Originally posted by toomey450
not sure what kind of main jet it is. they just sent it to me with the toomey slip on pipe.

How do you like the toomey? And do you have a soundclip?
Ive always been curious about them because they advertised for the yfz and I wanted to know how their 4-stroke pipe is.

Posted by: ohsobad_chevy

quote:
Originally posted by toomey450
not sure what kind of main jet it is. they just sent it to me with the toomey slip on pipe.

Well, does it have a K and a star on it or just a size number.

Posted by: toomey450

it had a star on it and all the jets that came with the gytr jet kit have stars to.

and the pipe is off the chain if you like it loud and mean. it gave it a lot more horsepower and it made it a lot louder, its just the jet that came with it isnt quite working for me.

Posted by: SMS

It seems we usually end up with this combo in Ohio

55 pilot
165-170 mj
we use the magnum needle 2nd clip
and we like it better than the other needle we have tried
and we use the r&d adjustable leak jet bowl adjuster screw 2 3/4 out
we also use the r&d flex jet fuel screw 2-3 out

Pipe and air box lid off
The magnum jet kit comes with needle and 165,170,175 main jet we sell all the iteams need to jet your YFZ as well.

Posted by: dingaling02

I just changed the jetting on my stock 06 yfz. I wanted to ask a few questions before I starting riding it. I just installed a slip on HMF pipe, and used dynojets jet kid for the 450. I went with their specs and they are way off, as to what everyone else runs.
I live in indiana, so around 700-1300 ft, and temps in summer are avg. 80, starting here in a month or so, it will be around 30-40.
this is what I started with, and we'll see where I should be. I used all Dynojet stuff, so their needle, 3rd clip, a 150 main, and a 45 pilot. I run the lid off with stock filter, as of now, I just ordered a k&n filter, and will mostly run with the lid off, except for casual riding around the farm, I put the lid back on.
Is it okay, to run the lid on and off, and not do much changing.
Also, I have the a/f needle turned out 1 turn. That sounds majorly different than everyone else. I wanted to run these numbers by you guys first, before I started riding. I am a newb to most of this, but have done a lot of reading and following you guys write ups!!

Thanks in Advance,
Corey P

Posted by: SMS

From what I know dyno jet uses different jets and needle setup than what most of us use. As far as running lid on and off it needs to be jet each way.

Posted by: dingaling02

would you suggest ordering a new jet kit. I would like to get what everyone would suggest as the best.... Any information would be great. I know that their stuff did seem quite a bit different from that of every other brand.

Posted by: SMS

If it was mine I would use the same set up we all have.

Posted by: dingaling02

SMS, I am kind of starting to think you might be right, I just hate to maybe admit defeat on what I already have!!! I will get back with you about your pm as well..Thank you very much.

Now, I talked to dynojet today, and they are the most erogant people I have ever met. I told them that everyone else is using a larger sized jet, than what they even offer. The guy says, why is that, and i tell him, most are using a 168+ main jet, and I am using a 150. He says, what is infront of the 150, and I said CJ, he then proceeds to ask what is in front of everyone elses, I say nothing. So, he tells me that is the reason, they are not the same, so leave it at that. I guess that wasn't good enough. He just said dynojet is tried and true, so why look for suggestions. That really disgusts me, to hear not to ask questions, just do what the paper says. I guess if these quads for 500 bucks, I wouldn't care, but I've got 7K in this, and can't risk tearing it up, because they don't want to compare themselves to someone else.

Morale of this story: I CJ150 Dynojet is not a typical 150, it is something completely different from what everyone else has, and cannot be compared, IM TOLD!! I guess they are venturi jets, which I understand, but i have no way of cross referencing to anyone..
Anyone else have any luck with manufacturers like I did!!
Thanks everyone for all of your help!

Posted by: SMS

I just try to help to save everyone time and money, so they can ride!

Posted by: 450Rrider13

i live in green bay wisconsin and im getting my quad set up for the winter so around 0-30 degrees. its got a powercore 4 slip on and a mega bomb header. any ideas on what i should run for jets??

Posted by: SMS

62 pilot 175 mj fuel screw out 2 turns I like the ndsr needle 3rd clip

Posted by: Bill Fuller

62 Pilot Jet?????????????

Posted by: BennyYFZ

I'm new to the jetting stuff, but I want to learn how to jet it myself and see good results. Is this a good starting kit for me? My mods are in my sig, and I'm fixin to add a 15t front sprocket on pretty soon.

http://cgi.ebay.com/ebaymotors/YAMA...
essories

Thanks for all the help guys

Posted by: ohsobad_chevy

62 pilot is WAAAYYY too rich, I would start with a 48 and go from there.

Benny, If I were you, I would order the "NCVQ" needle and buy your jets separately (keihin jets) from your dealer or you can get them from jetsrus.com

With your mods, I would start with a 175 main, 45 pilot, NCVQ needle on the 3rd clip and 2 turns out on the screw. That will get you close.

Posted by: Bill Fuller

Although I agree with ohsobad I would like to point out the NVCQ needle is very rich. I had quite a time with getting it right. I like the 50 pilot, NDSR 3rd clip down and 170 main. Fuel screw if you have on will need to be adjusted accordingly. It is also nearly impossible to jet one of these carbs while on the stand, you need to ride it after every change, the carb reacts differently when underload IMO. I would also recommend changing the leak jet to get rid of the bottom end bog. Alot of the bog can be removed by proper jetting but you still will have a slight hesitation, until you get that adjusted.

Good Luck

Posted by: Bill Fuller

Benny the jet kit you show doesn't state wich needle that is. I would contact GTthunder.com and get his kit or order your carb parts from carbparts.com they have the best prices for individual jets, I think when I orderd the jets where like 2.50 or so each. I bought from 160-180 cost me like 20 bucks or so.

I can't see what is in your sig to help much more, I turned off sigs ALONG time ago.

Posted by: BennyYFZ

hey guys, thank you for the information!

I will see what I can come up with here w/ jetting changes.

Bill, my mods are:

2004 Yamaha YFZ450
Ron Woods full exhaust
Cam mod
CP Race Piston 94mm
Velocity Intake w/ airbox removed

I'm in DFW, Texas which is roughly 600ft above sea level. Temps are roughly in the 50's these days.

Posted by: WoodsRacer16

Hey i have just got in to racing xc this summer in middle tn and i never jetted a quad in my life.I have a stock 07 yfz 450 and i just got my new hmf pipe.Could yall just tell me what i need to do and how to do it lol... im a little lost on it...thanks

Posted by: ohsobad_chevy

quote:
Originally posted by WoodsRacer16
Hey i have just got in to racing xc this summer in middle tn and i never jetted a quad in my life.I have a stock 07 yfz 450 and i just got my new hmf pipe.Could yall just tell me what i need to do and how to do it lol... im a little lost on it...thanks

Start with a 170 main, 45 pilot, 3rd needle position, and 2.5 out on the screw. That will get you close.

Posted by: Bill Fuller

45 pilot is to lean. I wouldn't put anything less than a 48. NSDR needle 3rd clip 170-175 main with open airbox.

Posted by: ohsobad_chevy

quote:
Originally posted by Bill Fuller
45 pilot is to lean. I wouldn't put anything less than a 48. NSDR needle 3rd clip 170-175 main with open airbox.

Jetting isn't the same for everyone, temperature, elevation, different pipes, carbs, intakes, etc etc.
There is no way to tell him EXACTLY what he would need. That will get him close.

I have a sparks pipe and FCI intake on my 07 and a 48 pilot is way too rich, even in the colder months.

Posted by: Bill Fuller

Except for the fact that he lives an hour away from me with close to the same set up. And I agree that it's only a starting point and I UNDERSTAND elvation, humudity, temperature, setup ETC......

Posted by: mxpimp2000

can anyone help me out on jetting

HMF slipon
cam mod
uni filter no lid
13:1 piston
168 main
48 pilot
2 1/2 turns out
stock needle non adj
temps are around 80-90 when i ride and im 500-550 ft above sea level in the lower Ky area

bike is hesitating when u punch it from 1/2 throttle and if u hold it at half in nuetral it will cut in and out and backfire when u punch it from 1/4 it dies people are telling me its my jetting i just had motor rebuilt and changed exhaust from a TC full system to a hmf slipon with stock header, i didnt mess with the jetting any

Posted by: ohsobad_chevy

Adam,
We have answered you many times in your thread. We told you what jets/needle to order......have you done so??

Posted by: yfz4506

What jetting should i use, i have
GYTR slip on
K&N filter with pre-charger baggy NO LID
05 bottom end with 06 head

Posted by: ohsobad_chevy

quote:
Originally posted by yfz4506
What jetting should i use, i have
GYTR slip on
K&N filter with pre-charger baggy NO LID
05 bottom end with 06 head

Start with 170 main, 45 pilot, 3rd clip on needle and 2 turns out on the screw.

Posted by: erikschmitt

04 yfz 450
white brothers e2 slip on
everything else stock air box lid is on
where should i start with the jetting?

Posted by: liquidivide300

I just purchased a 2007 yfz last thursday. The bike came with a full rocket exhaust, and uni air filter and a few jets. the owner i bought it from said the main jet in the carb was stock. I took the bike home and it ran like crap. It was missing in every gear and had no power. i was getting beat all day by a stock 2006 ltz 400. I changed the pipe and header back to stock and was still missing in the low gears. 3rd through 5th it ran awesome. I do a lot of fast tight woods riding about 1500 to 2200 above sea level. I would like to keep it mostly stock for now. Dose anybody know the stock pilot/main jets. Ride in 45 to 90 degree weather. Any help would really be appricated.

Thanks

Posted by: ohsobad_chevy

quote:
Originally posted by erikschmitt
04 yfz 450
white brothers e2 slip on
everything else stock air box lid is on
where should i start with the jetting?

Start with a 45 pilot, 170 main, 3rd clip needle and 2 turns out on the screw.

quote:
Originally posted by liquidivide300
I just purchased a 2007 yfz last thursday. The bike came with a full rocket exhaust, and uni air filter and a few jets. the owner i bought it from said the main jet in the carb was stock. I took the bike home and it ran like crap. It was missing in every gear and had no power. i was getting beat all day by a stock 2006 ltz 400. I changed the pipe and header back to stock and was still missing in the low gears. 3rd through 5th it ran awesome. I do a lot of fast tight woods riding about 1500 to 2200 above sea level. I would like to keep it mostly stock for now. Dose anybody know the stock pilot/main jets. Ride in 45 to 90 degree weather. Any help would really be appricated.
Thanks

Put the pipe back on the bike and start with 170 main, 45 pilot, 3rd clip needle and 2 turns out on the screw. Should get you close.

Posted by: liquidivide300

Matt,

got your replay however i want to keep the bike stock so when you mean pipe do you mean the rocket or the stock. stock is on it now and quiet which i like because i ride in an residential area to want to make my neighbors to mad.

thanks,
glen

Posted by: ohsobad_chevy

quote:
Originally posted by liquidivide300
Matt,

got your replay however i want to keep the bike stock so when you mean pipe do you mean the rocket or the stock. stock is on it now and quiet which i like because i ride in an residential area to want to make my neighbors to mad.

thanks,
glen

I was thinking that you were going to put the aftermarket pipe back on. With the stock pipe, I am not for sure. Probably around a 45 pilot, 168 main and 2.5 turns out on the screw would put you pretty close.

Posted by: Backstabber

We are going to tune my friend's YFZ this weekend. We ordered a special screw driver for reaching the A/F screw. I just wanted to double check and make sure we ordered the right tool. Your help would be much appreciated, thanks!

The tool is the "Motion Pro Pilot Screw Adjust." Its on motosport.com under tools and accessories.

Posted by: ohsobad_chevy

quote:
Originally posted by Backstabber
We are going to tune my friend's YFZ this weekend. We ordered a special screw driver for reaching the A/F screw. I just wanted to double check and make sure we ordered the right tool. Your help would be much appreciated, thanks!

The tool is the "Motion Pro Pilot Screw Adjust." Its on motosport.com under tools and accessories.

You got the right one. I would have just ordered an adjustable screw instead of the bent screwdriver. The R&D remote fuel screw is awesome!!

Posted by: Backstabber

quote:
Originally posted by ohsobad_chevy
You got the right one. I would have just ordered an adjustable screw instead of the bent screwdriver. The R&D remote fuel screw is awesome!!

Ok, great! Thanks for the reply!

Posted by: Pack

Ok, I have many questions:

1: Concerning an air filter. I ride trails often. I ride in water, jump just a little, drag race, and dirt roads. What's a good one for me? Also, what's a good lid to go with? My stock one fills up with water often.

2. Should I find a jet kit somewhere to buy, or buy the jets seperately due to the price, even though I have no idea how to install them.

3. If I did buy them seperately, are they hard to install? How much would it cost to get them installed?

4. What's this "fuel screw" and where can I find it? Do I have to buy it? How's that whole thing work.

I live in Missouri, so the elevation jumps around, since there are hills everywhere. So, anything you want to add for extra advice, please feel free.

Thanks, guys.

Posted by: BrettOaktree

i ride in similar conditions minus the water and i have a k&n with the pre filter, i like it, but i dont have my lid on so i dont have suggestions on a lid, and i think you should buy a jet kit just to get a good base, i got an fmf jet kit and it had really good instructions so it was kind of a jet kit for the average newbie like myself, and after that if u start doin more mods most of the time you only need to up your main jet so u can just buy those separately after some time, and id do it yourself its really not that hard to jet if you have good instructions and my fmf kit told me how to get to the fuel screw and how to adjust it.

But im wondering if my setup sounds alright to you guys?

Hmf sport series slip on, airbox lid off with a k&n and a prefilter, and the cam mod done

The elevation around here usually floats between 0-1000 feet depending on where i am, im looking for a good all year round setup the temps now are around 70-85 and in the winter the only time i go out is if its atleast 30. Right now im running a
48pilot
165 main
needle on the 3rd position
1 turn out on the fuel screw

feel free to leave your opinion, thanks

Posted by: quadboy-55

quote:
Originally posted by Pack
Ok, I have many questions:

1: Concerning an air filter. I ride trails often. I ride in water, jump just a little, drag race, and dirt roads. What's a good one for me? Also, what's a good lid to go with? My stock one fills up with water often.

2. Should I find a jet kit somewhere to buy, or buy the jets seperately due to the price, even though I have no idea how to install them.

3. If I did buy them seperately, are they hard to install? How much would it cost to get them installed?

4. What's this "fuel screw" and where can I find it? Do I have to buy it? How's that whole thing work.

I live in Missouri, so the elevation jumps around, since there are hills everywhere. So, anything you want to add for extra advice, please feel free.

Thanks, guys.

ok, jets are probably one of the easiest things to install if you have patence to get the job done right because you have to try many different jets to get it right.

basically, there are two hose clamps on youre carburator on each end. loosten them and turn off your gas. then being on the opposite side of the quad (from the exhaust), pull the bottom of the carb closer to you. remove the tranny vent hose (grey hose with a spring on it) put it too the side and cover the hole with electrical tape. at the bottom of the carb you will see a nut (17ml) get a 17 ml wrench and slowly twist it off with a soda can under neath the carb with the top cut off. the gas will drain from the nut and make sure you get most of it in the can (thats why you put the electrical tape over the hole) once no more gas is comming out you can take off the nut. under the nut you will see two copper bolts with holes in them (these are youre jets) the big one that is closer to the nut you just removed is the main (the big one) furthur off to the side is the pilot jet. you can remove the pilot with a flat head, the main must be removed with a 7ml ratchet or screwdriver with a 7ml attachment. then screw the new jet inplace of the other jet and install your new pilot. reinstall the nut, hose, and replace the carb to its origonal position, tighen all clamps, and turn on the gas.

for the needle, on top of the carb (seat off) you will see a cover that says CR in big letters, it is held on with two allen screws, remove this cover. underneath (GAS OFF!! for the next part or you'll flood your bike) put you quad to ful throttle, this will pull the needle up. there is a silver allen bolt/needle cover you must remove, use a set of needle nose pliers once loosened to remove it. dont drop it down the carb. now you can see the part of the needle (NVCQ) that the e-clip goes onto, use the pliers again to pull the needle up and out (the needle isnt screwed on or anything besides the silver cap removed earler.) once the needle is removed you can replace it with the one that came in youre kit, once you put the e-clip on.. that is. (hint: try with youre new needle put the clip on the 3rd from top groove, that usually works best for most people) replace youre needle, put your quad to full throttle and screw in the silver allen retaning cap, then install the cover with the with the two allen screws.

the fuel screw is covered behind a metal plug you must drill through and pull out. then the screw is visable. turn it to adjust youre a/f ratio.

heres my quad so far.
mods: stock pipe, core removed, lid off, twin-air filter, Dynojet kit

main: 144
pilot: 42
needle: (NVCQ) 3rd clip from top
fuel scew: 1 turn out from seated.

Posted by: mxpimp2000

im needing some help finding a 50 pilot jet.. i have 2 48's and only using 1 its a little lean right now anyone have a 50 to trade for 48?

my local dealer trades jets but dont have a 50

Posted by: ohsobad_chevy

If you kind find anyone to trade, try jetsrus.com

Posted by: mxpimp2000

found one

but i want to ask why my bike would need a 50 i dont see any ppl using 50's that seems high for a pilot jet.

i just recently cut out my airbox but still has the sides and bottom i just cut the rear out and the plastic around the battery box so the filter is pretty exposed gettin plenty more air than was. i havent messed with the main or needle or anything seems to run great except for 1/5 or 1/4 throttle in nuetral it cuts in and out and if u tapp it sorta fast no more than 1/4 throttle it cuts out and backfires

Posted by: Bdav450

when you change jets do u need to leave the min jet adaptor in

Posted by: mxpimp2000

http://www.youtube.com/watch?v=pdCuhPyTckE

Posted by: quadboy-55

quote:
Originally posted by Bdav450
when you change jets do u need to leave the min jet adaptor in

only if you have a Dynojet or FMF kit!

keihin jets dont have an adaptor so there isnt one to swap. and there is no such thing as a main jet adaptor for Keihin jets.