Honda FR600 Owner's Manual page 12

Fuel
Remove the gas cap and check the fuel level. Refill the tank if the level
is low.
Fuel tank capacity: FR600: 3.6 Q (0.95 US gal, 0.79 Imp gal)
FR800: 6.0 Q (1.59 US gal , 1.32 Imp gal)
Gasoline is extremely flammable, and gasoline vapor can explode.
Use extreme care when handling gasoline.
Refuel in a well-ventilated area with the engine stopped. Do not smoke
or allow flames or sparks in the area where the engine is refueled or
where gasoline is stored. Avoid repeated or prolonged contact with
skin or breathing of vapor.
After refueling, tighten the fuel tank cap securely. If any fuel was
spilled, make sure the area is dry before starting the engine.
LEVEL MARK
Fuel recommendation
Use unleaded gasoline with a pump octane rating of 86 or higher.
This engine is certified to operate on unleaded gasoline.
Unleaded gasoline produces fewer engine and spark plug deposits
and extends exhaust system life.
Never use stale or contaminated gasoline or an oil/gasoline mixture.
Avoid getting dirt or water in the fuel tank.
Occasionally you may hear light "spark knock" or "pinging" (metallic
rapping noise) while operating under heavy loads. This is no cause for
concern.
10