lineaway

If you have good spark, but the bottom end is old it could be mains and/or seals.

I`ve done a complete rebuild. The kick starter was the hardest part. The only thing I can remember was the kicker had to be about three o`clock for it to finally hit the sweet spot to go together.

If you are lucky it could be a dirty carb. At the worst the main bearings and seals are going bad. You could pop the flywheel cover off, grab the flywheel and check for play. You could also have an air leak at the intake boot, that can be checked while running. Use contact cleaner or some other spray while idling and spray around the intake.

https://www.youtube.com/watch?v=WSahhifhSfo

Like I said, go up two sizes on the pilot. If it fixes it, come summer go down one size and see how it is. Funny thing about all the jetting Gurus out there, the pilot jet flows from idle to wide open. If the bike is running, the pilot is flowing.