Main Motorcycle: 12 Rocket Roadster
Join Date: Apr 2007
Location: Northern, Ontario
Other Motorcycle: 03 America
Use a motorcycle specific synthetic oil. Standard synthetics for cars (diesel engine excluded) have friction modifiers which could harm your clutch. Diesel and Motorcycle specific oils don't have them (JASO rated) and are the best oils for combined engine/transmission lubrication.
The reason to use a synthetic oil is due to it's ability to maintain it's multi grade capability. Dino oils loose their mult grade capability rapidly. A 15w50 dino oil will become a 15 weight in no time due to the shearing action of the transmission gears which have little effect on synthetics.
Can't wipe this smile off my face!!!!