mooman007uk

a tank that lets in air is not going to affect the running...they're vented after all to allow air in anyway....if you're getting bubbles in thr top ball in the carb then it's probably the carb...as slaw says i think it's been your carb from the get go after seeing the video you posted...i did say back then that it was doing exactly as my buggered 813 did. i fear you have stripped down your engine unnessesarily as the carb was the issue all along and helicoils can be done with the engine in one piece. And i should have thought about it yesterday cos DDM deal of the day was 813's for 28bucks