bogging......

[stevengates45]

I just got my bike back together & put a Wiseco 11:1 compression piston in it. Anyway, before I put the piston in I had a 125 jet in the carb & still do but whenever you would push the gas in fast & let it out quick it would rev good. Now if you try to do this it bogs & then revs. What do you think I should do? Im on a really tight schedule now these days so I dont have any time at all to trouble shoot the problem. ALL help is appreciated! :)

you definitly have a jetting issue,,is it at the bottom or the top of the motor revving???

[MIKE400EX]

Also check and make sure your idle RPM isn't too low. (That's if the bog is just off idle).

[stevengates45]

bottom

I had a similiar problem to that when I added the powerbong and I had to up the pilot jet and adjust the fule/air screw,,fixed it right up.

Where did the #125 jet come from?? The 400 comes stock with a #148. They are somewhat lean from the factory, so most people jet richer, not leaner--particularly after engine mods.:)

[400exRacerX]

Originally posted by rockosmith
Where did the #125 jet come from?? The 400 comes stock with a #148. They are somewhat lean from the factory, so most people jet richer, not leaner--particularly after engine mods.:)

He most likely has a 300ex.;)

your machine is running lean..i know bcause my 400 did that w/ the new fcr carb

[stevengates45]

Alright, thanks alot guys. I just got in from being out of town, im most probably going to mess with the air & fuel screw today & see how it does. Ill let yall know how it goes. later Thanks

[305exracer11]

mine did the same thing then i but some cam2 blue racing gas in it

[beerock]

talking about adding race gas doesnt help anything.

Race gas will make a bike run richer. but cost$$$$$$$$$$$$$$$$$$$$$


with a higher compression piston you are going to have to jet richer, if stock is 148, I would go with a 155 and see how that works.

WHY was there a 128 main jet in there?

Did you happen to buy your quad from someone who lives in the mountains?

that is crazy lean.

Or was that a typo when you wrote that?

Try a 155 main

the air screw should be played with 2 much, normally you set it at idle and leave it alone(set it so it revs the highest it can when you screw with the screw)

Usually 2 and a half turns out from all the way in is a good reference part.

[stevengates45]

theres a 125 in there because i have a 300ex, not a 400ex