So I know there r like a million and 1 oil threads on here but most are dated so I thought why not get a fresh perspective. The guy I bought my bike of was running full syn ams oil 10 40. The mechanic(over 30yrs there) at the shop I've been going to recommends semi syn. He says it's not as "slippery" and that with full syn the clutch will start slipping over time. So what do u guys think?