Just picked up a 04 yfz450. It runs good except on the top end. I'll be scooting along real good and all of a sudden it will cut out. It seems like its trying to die.
The guy I bought it from said he had to put a bigger main jet in it when he got it. I haven't had a chance to check it. Is this a symptom of running lean or rich?

 

<div class="FTQUOTE"><begin quote>Originally posted by: Koopa

Just picked up a 04 yfz450. It runs good except on the top end. I'll be scooting along real good and all of a sudden it will cut out. It seems like its trying to die.

The guy I bought it from said he had to put a bigger main jet in it when he got it. I haven't had a chance to check it. Is this a symptom of running lean or rich?</end quote></div>


Yup, thats prolly it. To big of a main will make it cut out on top. We had the same problem.

 

What exactly do you mean at top end.

Is it at the top of each gear if so you are probally hitting the rev limiter.

 

No not rev limiter. Once it chokes and comes back I'll continue accelerating but, ya I mean high revs.

 

Try turning your headlights on, the 04's have stator problems.

 

take your airbow lid off it is running too rich and flooding the carb. i had the same problem.

 

take your airbox lid off it is running too rich and flooding the carb. i had the same problem.

 

Thanks for the replies guys. I went to little sahara here in ok. this weekend and didnt have any probs at the rev levels that I commonly ride. Still have probs if i really rap it out. My box lid is off and I have a pro flow kit with a K&N and outerwear, so its getting all the air i can give it.

supraomega your comment has me thinking. The guy I got it from said he just replaced the stator because he heard that when you put on the kill switches like he did it weakens them or something. Anyway, he removed the headlights also. So what do you think? Should i put some headlights back on? I planned on it anyway. Should I remove the kill switch?

*The kill switch I am referring to is the emergency clip on style. Not sure what they are called.

 

No the killswitch shouldn't affect it you can run with the headlights on or you can buy a resistor kit wich will do effectively the same thing. Did he put a stock stator in?

 

I believe he did. He didn't specify.