200 m backfiring

[lowridin247]

at idle up to 1/4 throttle roughly it backfires. can someone tell how to check the cam timing ? and what else i should try to help with the backfiring

tonight i adjusted the cam chain tensoner and turned the a/f out a bit its just over 2 turns .
still spits a bit when reving up 1/4 throttle.

did a plug chop with and its lean i changed the main from 95 to a 100 cause it was showing it was lean before and it seems a little better but not very much improvement