Yes I know what you mean about "If it aint broke don't fix it" but I've only had the bike a few months and can't be sure what been done in the past. So far I've balanced the carbs, changed oil & filter and set the air screws on 3 of the four carbs ( as found not correct) stripped cleaned and greased the brakes and the bike is much smoother than it was. I still have not got starting cold sorted (full choke, half, non?) it always needs some throttle but I'll keep experimenting.
Cheers Andy