Join Date: Nov 2009
Location: Lander, Wyoming
The 20W50's, 15W50's and many 10W40 Automotive oils (as I understand) do NOT have the super slippery additives of the 5W40's, 10W30's and thinner grades called for in the modern automotive engines due to their tighter clearances. But it is highly advised to not use any automotive oil which carries the "Energy Conserving" label on it, regardless of grade.
The Arco Graphite oil of the mid to late 70's caused nearly instant clutch slippage in at least 1 Kawasaki H-1 500 triple. That oil must have even caused some automotive problems, because it wasn't on the market for very many years.
Modify at "YOUR OWN RISK"!
Still riding my 1987 KL650-A1. 85,000+ miles & counting