Hi, Jimmyvalenti excellent question, before I begin let me address motorcycles with valves and seats designed to run on leaded fuel issue, you can run unleaded fuel without a lead additive with no problem just replace the valves and seats with ones designed for unleaded fuel the next time you need a top end overhaul. In extremely rare cases some higher compression engines will ping using the highest octane graded unleaded fuel available in these cases the use of a lead additive or aviation fuel is recommended. Octane rating is a measure of a fuel's ability to resist 'knock'. The octane requirement of an engine varies with compression ratio, geometrical and mechanical considerations and operating conditions. The higher the octane number the greater the fuel's resistance to knocking or pinging during combustion.
The recommended octane rating for most motorcycles is usually octane 87, but be sure to check your bike's owner's manual. Ordinarily, your motorcycle will not benefit from using an octane higher than recommended in the owner's manual. However, some motorcycle models have high-compression engines and electronic controls, which are designed to benefit from the greater power output and improved fuel economy of high-octane fuel. Since octane requirements can vary with operating and environmental conditions, your bike may need a higher octane fuel than recommended to prevent knocking.
Bottom line, use the lowest grade octane that gives you acceptable performance without knocking or pinging.
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