[313ex jetting] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

Pages:1

313ex jetting
(Click here to view the original thread with full colors/images)

Posted by: 250xsupertrapp

my buddy has a 313ex and it has a stage 2 dynojet kit, it runs lean on the top end so what main jet should i get.

Posted by: JIMFROMTEXCO

well what size main is in it now? what is it running like now? popping on decel? what else is on the bike? pipe, filter, airbox lid, and is it a high comp piston?

Posted by: bwamos

What else is done to it?

Bored I assume, not stroked.

Header pipe oversized or stock?
Free flowing silencer or quiet core/baffled?
Stock air filter or aftermarket? Foam or Gause?
Air box lid on, off, or vented?
Cam aftermarket or stock?
Stock carb or 400ex carb?
Standard or oversized valves?
Ported or stock head?

Dynojet kit isn't going to be big enough. Airbox lid off w/ typical open exhaust and aftermarket filter I would say you'd need around a 135 Keihin main jet, 40 Pilot, Raise needle 1 slot as a starting point. But if you have any other mods, or have the airbox lid on or quiet core you're jetting will be different.

Give us a bit more info and we can get you a good starting point.

Posted by: 250xsupertrapp

dg exhaust
k&n filter
vented lid
stock carb and head
not stroked