I'm running longer bars on the larger saws cutting 40"to50" diameter tree trunks at a saw mill. 20 cords of wood broke them in. My older husqvarna 2100 (99cc) saws needed very little break in.
Not sure how vintage your bike is. I used to race my 79 maico 400 with 85:1 belray mc-1. The bike loved it and gave me phenominal top end life for an air cooled race bike. Even my dads old 1960 mercury 6hp outboard liked the 85:1 belray synthetic very much. It went from a 100 pull starter to a 2 pull starter. I would think the amsoil would work excellent. Cam.
I have some 100:1 optimal but never tried it. Some ran it the chainsaw speed competition at the local fairs. I plugged the governor's and put a larger drive sprocket and set the rakers at .060" for pine. Doing 8 cuts in 17.5 seconds wasn't too shabby.
