MCN in no way endorses the products of Amsoil, or any other lubrication company. The new American Petroleum Institute oil performance rating, SJ, has now been introduced, and again motorcyclists are being cautioned that automotive engine oils are not to be used in motorcycle engines. Sadly, these recommendations are based purely on profit, not the protection of your bike. The new SJ standard requires that oils marketed today meet stricter fuel efficiency standards as well as lower phosphorus limits, for catalytic converter protection, than did their predecessors. Some new oils have managed to meet those requirements by way of friction modifiers for fuel economy, and all of them contain lower levels of anti-wear additives in order to lower their phosphorus levels.
Friction modifiers cause wet clutches to slip, according to motorcycle oil proponents.
They also maintain that lower levels of anti-wear additives allow excessive wear in motorcycle engines and transmissions. Of course, these same motorcycle oil proponents indicate that motorcycle specific oils pose neither problem. However, the claims against automotive oils just don't wash. Clutch slippage in motorcycles is mostly caused by deposit and varnish buildup on clutch faces. Their superior anti-wear chemistry has been proven in the lab and on the road.