I recently installed the 686 big bore kit, port and polished my head, hot cam, and installed a k and n air filter. Im installing a dyno jet kit and I dont know what size jet to go with. It has a stock 145 and the jet kit calls for a 165, but thats not counting the big bore. Any suggestions?

 

Keep in mind that the Dynojet jet numbers do not match mikuni jet numbers, so a 165 Dynojet jet is not the same as a 165 Mikuni jet. If Dynojet is recommending a 165 main jet for a stock bore engine, I would think a 185 main jet would be a reasonably safe starting point for a 686. Good luck with it.

DV