choke problem

[wheeltrax]

I just got back from racing today, it was great. In practice i was going around the track and then it started stuttering. the choke went from off to half choke. I put it back to off position. I was riding around the track again, and it did it again. It has never done that before. It was cold out so i was thinking maybe something froze and wasnt keeping it place.. not sure? this is on a 400ex with stock carb. I know alot of ppl run the 42 pilot, and i was wondering if you can run the 42 pilot in summer too or if it runs too rich? i thought about throwing the 42 pilot in so it would start easier in winter, but i was wondering if it would work in summer too..

[quadsquadron221]

You should take the carb off, or at least take your jets out and blow them out. If you get even a spec of dirt in your jets it wont run. If you have to run it with the choke on you are probably running way to rich and can burn up the motor. Any way i would give the carb a good cleaning. And then mabey richen it up a little bit.

[mojoe2878]

you can run the 42 pilot in both winter and summer, you may need to adjust the air/fuel screw some when the temp changes, but thats easy and quick.
as far as the choke goes, look on the side of the carb. where the choke lever is and there is a small plate with 3 holes in it, there is a very small ball behind that plate that lines up with the holes when the choke is in different position to hold it there. check to see if the plate is bent or if the little ball is missing and not hold the choke in place.

[wheeltrax]

Originally posted by quadsquadron221
You should take the carb off, or at least take your jets out and blow them out. If you get even a spec of dirt in your jets it wont run. If you have to run it with the choke on you are probably running way to rich and can burn up the motor. Any way i would give the carb a good cleaning. And then mabey richen it up a little bit.

I didnt say that i had to run it with the choke on, I said that when i was riding it the choke went on by it self. thanks for replies