[Raptor 660 Carb Jetting] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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Raptor 660 Carb Jetting
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Posted by: Honda 250r 001

Ok this isint a 700 but its close and i need help.

I took the carb off and i found out it has 2 different size mains in it. is this suppose to be?

anywhoo

what jets should i run with a slip on pipe and a intake?

i have in it currently.

155 main on the left side, 160 main on the right

25 pilot in both sides

needle on the middle clip.

help?

i think the pilot is off becaus this thing starts like a DOG, should i go up or down on the pilot? it also backfires quite a bit when you go in 5th and let off the throttle.

im thinking of going down on the pilot one? good idea or not?

Posted by: yfzrider690

I used to have a 660 before my yfz and it was a pain in the ***** to jet. The right carb should have one size bigger jet than the left side. I think I was running about the same jets that you are. If it is backfiring on decel than you need to bump up the pilot one size, this could also be the reason that it is a pain to start. Mine fired right up but I can't remember what size pilot I was running, I think it was a 27.5. If you go down on the pilot than it is gonna be running more lean than it is now and probably backfire more. Try that and let me know how it works for ya.