I know, I know, trial and error but this is wierd. while jetting my Predator my friend had me jet up his Raptor. It ran fine before but a little lean (greyish color on the plug) so we went up a little on each carb. Why they use different sizes on each one is beyond me but they do, factory is a 140 and a 145 we went to a 150 and 155. Now, it sputters and pops from 3/4 to wot. It seems like it is starving bad but you would think it would have been worse with the smaller jets. It has a slip on and 12- 1 inch holes in the air box with a replacement UNI filter. Also, my Pred is doing the same thing I went to 170 main and 50 pilot and a UNI clamp on filter directly at the carb. The only other thing I have doneto mine is a Polaris slip on. Any wisdom would be appreciated. By the way we are at about 1100 feet. Help???

 

Jetting

Might shed some light....

 

go down a size on the main if it sputters ( bogs ), too rich

 

Well I finally got it. Trial and error I guess was the key. On the Predator I ended up with 160 main, needle on the second notch from the top, 50 pilot, and UNI clamp on filter. Wow, what an improvement over stock!!!!!! Side bonus no more leaking air box tube (the one from the carb to the box). I cannot believe that they did not make a rubber seal between them. Oh, well every manufacturer has air box issues.

 

By the way thanks for your help!!!!!