i have a o1 blaster and i live in ohio with dg silencer and k&n filter with the lid off and i tor it apart because i had a bad gasket so i done a little poring on the intake and exhaust .put i all together and i had a 290 jet in it .and when i took it for a ride it it sputtered on top end and i messed with the air screw. then i took the plug out and checked it was runing a whitish gray .then i messed with it for a while and just out of curiousity i threw a 250 in and it runs way better i dont have the top end sputtering .i checked the plug and it look almost just like the 290 did ...could some one give me a idea of the jet size i need..and what does it do when u move the clip on the needle could some one explain this thank alot

 

The clymer manual explains jetting pretty good, for about 30.00 its worth it.

 

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