RE: Welcome to Club SAITO !
That sounds just like my 100! I replaced the bearings, and now it runs and idles fine, but has no top end; my 82 spins a 14x4w or 15x4w harder! From what I've gathered, it sounds like my (and maybe your) cam timing is retarded. Just haven't had time to pull it out and re time it; hope that solves it. Kinda disappointed in mine so far...