jeting

Hi I just bought a 05 fc 450 that came from New York and I am in Kentucky it pops when you let off the throttle while riding, im guessing its a little lean on the carb should I try the fuel air screw or install larger idle jet?

I just picked up the new 650 motard from the dealer. Real sweet but I found it to overheat far to quickly. The dealer took it strait back and re jeted it from a 160 main to a 178 main jet. Seemingly end of problem and a lot more power. However I would appreciate anyone’s knowledge or...