That is a very good demo of clutch operation, did'nt even turn it into an ad for Castrol. The main thing is to check the can for no friction modifier. It has been my belief that any oil 10/40 or higher in viscosity rating is safe for the Valkyrie. 15/50 for me works fine. Hoser
When I was Moto Crossing in Japan I was burning Castrol 2 stroke oil and had Castrol in my crank case. Lets just say I had 2 more complete clutch assemblies ready to go along with the extra sprockets and chain and at LEAST one extra set of tires. I was well versed on the clutch that was in AND out of my yukamuka.

Very interesting tutorial on a clutch and the WHY of it's function. Course with the ritis getting better every day and the nimbleness missing from the hands and fingers-ain't in no REAL hurry to rebuild another clutch.

RIDE SAFE.