dajogejr Posted May 28, 2005 Report Share Posted May 28, 2005 I hang my head...as I must come to the HQ with a 4 stroke jetting question . Luckily...it's not my bike, but a buddies that I need to help get "right" so we can ride tomorrow. He's got an 03 raptor with ONLY a Yosh full exhaust and K&N. Way rich now...as his pipe glows red. I read up a bit, and saw a good tip about one of the carbs needing the bigger main jet...weird to a fellow shee owner. Anybody have a good crash course... I assume these are Kehins on there, and do they follow the same scheme as Mikuni's? (Larger number, larger jet)... I just want to get him running good for tomorrow.... Quote Link to comment Share on other sites More sharing options...
holeshotkid Posted May 28, 2005 Report Share Posted May 28, 2005 A glowing head pipe is not a sign that it's running rich, but instead its lean. Is the airbox lid still on? Try 25 pilots, air fuel screws 3 turns out, 155 main left carb, 160 right, lower the clip on the needle one notch (forth groove from the blunt end of the needle) and you should be real close. Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted May 28, 2005 Report Share Posted May 28, 2005 A glowing head pipe is not a sign that it's running rich, but instead its lean. 374820[/snapback] Exactly...What jets were in there before the pipe and after the pipe? Quote Link to comment Share on other sites More sharing options...
Nightrider Posted May 28, 2005 Report Share Posted May 28, 2005 A friend went with the GYTR kit.155/160 main 25 pilot,2.5 turns out on screws and GYTR needle middle clip.Excellent setup with K&N powerlid. If your still running the lid,remove snorkle and go with 150/155 main.You can still use stock pilots 3.5 turns out with lid on. No lid at all and 160/165 main. Quote Link to comment Share on other sites More sharing options...
dnhyoung Posted May 28, 2005 Report Share Posted May 28, 2005 (edited) I read up a bit, and saw a good tip about one of the carbs needing the bigger main jet...weird to a fellow shee owner. 374788[/snapback] The reason for running 2 different size of jets is because the Raptor/grizzly engine has a 5 valve head on it, 3 for intake and 2 for exhaust. Now the reason for the different size of jets is because 1 of the carbs feeds 2 intake ports while the other carb feeds only 1 intake port. I helped my buddy tune in his bike after he went with the Looney Tunes exhaust, and had to eat crow because he told me the carbs took 2 diferent size jets and I called him a liar. Guess my passion for Shee's clouded my judgement. Oh Well, I'm still faster then him..LOL Wish I could be more help as to the size of jets...... Edited May 28, 2005 by dnhyoung Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 28, 2005 Author Report Share Posted May 28, 2005 My thoughts on a four stroke are rich and the extra fuel was burning up in the pipe. He had 150 and 146 mains. (Aftermarket jet kit) I stepped it down to 142 and 138, and it's running good. No popping, no overheating, nice plug color. Made two plug runs. The inside of the silencer was coated in black soot.... It seems to be running fine now...so, we'll cross our fingers tomorrow... Honestly...this bike is pretty beat up, he's going to rebuild it soon, big bore kit, etc., so...it only has to last a few rides... Quote Link to comment Share on other sites More sharing options...
race-a-holic Posted May 29, 2005 Report Share Posted May 29, 2005 (edited) It should run cooler with bigger jetting.Might want to tell your friend to keep a close I on his bike.If he is running with the lid off,it still might be lean.I think he should need at least a 160/165.He might be ok though. dnhyoung is right.One intake port is a lot bigger than the other because it's feeding two valves. Edited May 29, 2005 by RDZ350 Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 30, 2005 Author Report Share Posted May 30, 2005 Yeah...I read that about the carbs feeding valves... He ran airbox lid on all day. it ran pretty good. But, you can tell it is still not perfect...closer than it was, though. Told him to get authentic Kehin jets so the numbers match. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.