Kawasaki J300 - Owner's Manual > Fuel Requirements
Your Kawasaki engine is designed to use only unleaded gasoline with a minimum octane rating shown below.
Never use gasoline with an octane rating lower than the minimum specified by Kawasaki to prevent severe engine damage.
The octane rating of a gasoline is a measure of its resistance to detonation or "knocking". The term commonly used to describe a gasoline's octane rating is the Research Octane Number (RON).
Do not use leaded gasoline, as this will destroy the catalytic converter.
If engine "knocking" or "pinging" occurs, use a different brand of gasoline of a higher octane rating.
If this condition is allowed to continue, it can lead to severe engine damage. Gasoline quality is important. Fuels of low quality or not meeting standard industry specifications may result in unsatisfactory performance. Operating problems that result from the use of poor quality or no recommended fuel may not be covered under your warranty.
Fuel Type and Octane Rating
Use clean, fresh unleaded gasoline with an ethanol volume content not more than 10% and an octane rating equal to or higher than that shown in the table.
Do not use any fuel that contains more ethanol or other oxygenates than specified for E10 fuel* in this vehicle. Damage to the engine and fuel system, or engine starting and/or performance problems may result from the use of improper fuel.
*E10 means fuel containing up to 10% ethanol as specified by European directive.
WARNING Gasoline is extremely flammable and can be explosive under certain conditions, creating the potential for serious burns. Turn the ignition switch off.
Avoid filling the tank in the rain or where heavy dust is blowing so that the fuel does not get contaminated. WARNING Gasoline is extremely flammable and can be explosive under certain conditions, creating the potential for serious burns. Turn the ignition switch off. Do not smoke.