dead miss

After having my 300ex bored .40, a four stroke tech cam and rockers wiesco 11-1 piston and fmf exhaust it has a dead miss like the bike cuts off and cuts back on in the very upper rpms. I am running a 142 main 42 pilot. The plug looks ok should I jet up -down maybe check somthing else.

[coryatver]

It might be the kind of gas you are using. But i don't know much about it...

[max400EX]

buy some good quality gas. I allways use 89 oct Chevron and my quad runs fine. Dont buy the cheap crap like BP or MP.

[Leo]

Originally posted by max400EX
buy some good quality gas. I allways use 89 oct Chevron and my quad runs fine. Dont buy the cheap crap like BP or MP.

The book calls for minimum 92 octane...

Running 89 along with the sparks advance key is begging for trouble....


Wesley,

are you sure your not bumping into the rev-limiter..?

Leo

[TRX250EXER]

My quad is doing the same thing. I cant figure it out. Ive played with the mixture screw and stuff but I'm gonna get it running right this week. I have to, big trip this weekend to the badlands wit my friends. Cant climb and keep up good without full throttle rpms. I know its not the rev limiter because it does it in 5th gear too. and it only does this when its really cold (which would make you think it was too lean). I think it might be the gas too because I put turboblue in it and thats when I notice it. So the first thing I do is Im gonna suck the turboblue out and put in normal gas and see if it makes a difference. But if you get your 300 fixed first let me know so I know what to do.
Finally someone else has the same problem as I do.

[SGA]

Sounds like the rev limiter to me. On my 400 when i put the 14 tooth sprocket on it hits the rev limit pronto. Was kind of suprised, doesn't seem like i'm winding it that high. Had to learn to shift much quicker. Hardly ever hit it with the 15 tooth unless I wound it out hard in a lower gear. This happen to anyone else?

[R-Crazy]

i will tell you in a week or 2. I just ordered one for my 300. That would stink if that was the case for all quads. but mine does it sometimes now with stock gearing.

dave