Have been running this for years in my 04.yf450 as it has been the best at holding up to the wet clutch.
T-4 is a highly-refined petroleum blend lubricant designed specifically for motorcycle and ATV engines. It utilizes an exclusive blend of additives and polymer systems that resist high shock loads, high temperatures and shearing as well as eliminates deposits. T-4 is formulated to remain stable under peak operating temperatures and will provide excellent protection for integrated transmissions. The non-friction modified T-4 formula focuses on positive clutch engagement under high acceleration and deceleration loads.