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jetting
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Posted by: 88350R

im runnin a 190 right now and its burning too lean. a 195 is too rich...what do i need to change to get it right? i havent messed wth carbs much..what other jets or needle position can i change..? im runnin delta reeds, and a 38mm. its a 350 bored 60...i think the bore is 79mm.

Posted by: baker250r

or u could try a 193.

Posted by: 88350R

where do i get one of these 193s?
any ideas what size my other jets should be?

Posted by: YFZRob

I've never seen a 193, I think the hex style Keihin jets start going up by 5s once you go over 190. There's not much you can do to lean the 195 or richen the 190. 3/4-WOT is all main, so needle adjustments may not do anything for you. What needle and pilot do you have? I'd say at LEAST a 50 pilot and DGH needle. I have been going back and forth between the DGH and DDJ needle. The DDJ needle is nice and safe, but has a little miss to it at higher RPM around 1/3-1/2 throttle. I run either needle on the 4th clip.

I would assume you're a little too lean with the 190 and a little too rich with the 195?? That being the case, just run the 195 and replace the plug more often. It's better to be too rich than not rich enough.

Posted by: 88350R

alright. i realy dono what other jets im runnin, ct told me to run a 52 and i donno about the other one. ill prolly just put a 195 in there and like you said change plugs.

Posted by: YFZRob

Definitely check your needle. As for the pilot, a 52 sounds about right for a 350. I know there are guys on here who have said they run 50s on a 330 and 350, but I'd feel more safe with a 52 or 55 with a 350cc motor. What size carb do you have?

Posted by: baker250r

u can drill out jets too.

Posted by: wvspeedfreak

quote:
Originally posted by baker250r
u can drill out jets too.

Yeah,if you want to put them on a necklace.The hole in a jet is a precisely metered orifice.There is nothing precision or accurate about it once you slam a drill bit through it.

Posted by: wilkin250r

A 190 still sounds rather large, even for a 350 and a 38mm. I have a 38 A/S on my 340PV, and I'm only running a 168, and I think I'm a little rich.

Posted by: baker250r

i run a 190 on mine... and got the stock carb bored out 2 mm. runs great and mines only a 265

Posted by: baker250r

quote:
Originally posted by wvspeedfreak
Yeah,if you want to put them on a necklace.The hole in a jet is a precisely metered orifice.There is nothing precision or accurate about it once you slam a drill bit through it.

we drill out pilot jets all the time.

Posted by: 88350R

ill be happy to show you a picture of my plug...it looks brand new and ive rode almost a tank through it. no brown anywere.for now i put my 195 back in.

Posted by: YFZRob

I think you're not reading your plug correctly. It can take a while for the plug to get brown or dark on the portion you see at first glance. This area of the plug is not where you read to see if it's rich or lean!! There is a very small section of the porcelin that you look at, which is the base....all the way down inside the end of the plug. This base will get a ring around it with color. This is the color you need to look at and read. When I am being anal about plug chops, I actually cut the outside of the plug off so you can easily see this section. Others use a flash light and magnifying glasses to read the plug. Here's a photo of what I am talking about....

http://www.looseboltsmotorsports.com/images/atv/NGK0005.JPG

The dark ring (on the plug in the photo) at the base of the porcelin is what you read. If this is very light brown or white, you're LEAN, if it's dark like this photo, you're rich.

Posted by: 88350R

heres a pic, let me know what you think. Thanks

Posted by: YFZRob

Looks very rich to me. That lower black ring is what you need to read. Since it looks pitch black, your jetting is on the rich side. BUT, is that plug a result of a WOT plug chop? Meaning a full throttle blast all the way through 4th or 5th gear. At the top of the gear, hit the kill switch. Pull the plug and read that lower section of the porcelin. If it's dark brown to black, your 190 is too big. If it's light brown to white, it's too lean.

Use brand new plugs every time you do a plug chop. If you ride around for 20 minutes normally then do your WOT chop, you won't get an accurate reading. Make sure you also do part throttle chops to make sure your needle is set correctly. Do the same thing, just at 1/2 throttle instead of WOT.

Posted by: 88350R

that plug has about an hour on it i guess. right before i pulled it i went through 5th and then shut it off.

Posted by: YFZRob

Try it again with a brand new plug.....heat up the engine with an old plug and when you're ready to do your chop, throw in a properly gapped plug and hammer away, ending at high RPM in 5th. Pull the plug and go from there. If it's black like that when you're done, 190 is too much jet.

Posted by: 88350R

alrighty thanks. ill get back with ya as soon as i can get it done.