Full throttle miss/bog/bobble, stutter??

[dichdoc]

I'm playing with a 92 Yamaha Big Bear 350. At full throttle it kind of stutters and won't rev through it. Lacks Power etc. I can pull the choke while running WOT and it seems to run better and will accelerate. If I come to a stop with the choke on it will die. I tried moving the clip up 1 to lean it out and it ran the same and started to backfire when shut off. I went down richer with the clip and it got worse the farther I went. The plug was black and sooty before I started adjusting the clip and it was in the middle position to begin with. Any thoughts??? Travis

 

[AreWeThereYet]

Main jet

 

[dichdoc]

Up or down on the main jet?

 

[AreWeThereYet]

Large,r you are running lean

Needle adjustments is 1/2-3/4 throttle, main is 3/4 to WOT.



If there are no mods done and it is a stock bike, there may be something else wrong,.. like a vacuum in the intake boot.