Hey out there, has anyone been successful with jetting a stock 660 raptor with a yoshimura rs-3 full stainless pipe and a k&n filter with pro flow adaptor with ar box lid completly removed? i have mikuni jetting set at left carb #160 main and right carb at #165 main, mixture screw at 2.5 turns out, pops and backfires badly with lid off but runs great with lid on, i know its lean but can anyone tell propper settings with this setup?

 

well go to 170 and 175 that sould be good with your lid off...its always better to be a little fat than lean..But if you put them 170 and 175 in...ride it then pull your plug..and if it is white your lean..if it is tan you in the good and if it is wet looking and black you too fat..hope this helps

 

Set your mixture screws at 3 turns out with stock pilots and no lid.

 

170/175 or 165/170 would be better. Backfiring can also occur with exhaust leaks as well as valves out of adjustment. I would start with the jetting and then check for leaks.

 

Raptorschnutz,
It is time to update to a 700r.....lol
I don't want to keep beating you up Oldsmobile...
RaptordunerI
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