Is the carb boots blowing off still an issue with the 02 Raptors or did they fix this. Mine back fires sometimes when I first try to start it.

 

the carb boots were fixed on the 02. If your back firing it means your running a little rich. Your probably over chocking your machine on initial start up! Hope this helps!

 

So what was changed on the '02 Raptor to eliminate this problem? I am aware that the later '01's had revised intake boots.....but have not heard of any other changes. Thanks.

 

<< the carb boots were fixed on the 02. If your back firing it means your running a little rich. Your probably over chocking your machine on initial start up! Hope this helps! >>



If it backfires when opening the throttle, it's lean. A rich condition would result as a bog. You can also tell when it warms up. If it get's better, then it's lean. If it get's worse, then it's rich. I have an 01 that used to backfire when it was cold. I never had a problem with the boots, but then again, I piped it and rejetted it shortly after break-in. I think the carb boot problem was more of a air/fuel ratio problem from the factory. Yamaha jetted them so that the would run okay at most elevations, and the result was that us people at near sea level had to deal with a bike that ran VERY lean.

 

Right now it is usually 40 - 55 degrees when i start it. Is this the reason for the backfire? It just started about a week ago when I got it back from its tune after the 20hr break-in. It never happens when it is running just the first time I hit the starter button, and it is VERY loud. Thanks for the help.

 

A set of 27.5 pilot jets should solve your backfire problem.