Gasoline quality ?

[Gumby 1100_imp]

So everyone here runs 87? My mechanic said to always run 91 on motorcycles. Whats the difference?

Higher octane means it contains combustion inhibitors to prevent predetonation in high compression engines. If the engine is designed for a specific octane, it generally does you no good to go higher. In fact, if you go too high you may get incomplete combustion, fouled plugs and possibly more decel popping.

The only benefit to running slightly higher octane than what the manufacturer specifies is that it often contains more detergent additives and in some cases less or no ethanol.