Polaris 120 XC SP Youth Universal Owner's Safety And Maintenance Manual page 49

OPERATION
Fuel
The fuel used in the Polaris engine is as important to engine life and
performance as the lubricant used.
Most Polaris engines are designed to run on 87 octane non-oxygenated
or 89 octane oxygenated pump gasoline. There is a great deal of
variability in the quality of the 87 octane gasoline available across the
country. We encourage the use of premium fuel when possible.
A--30
WARNING
The engine exhaust from this product
contains chemicals known to cause
cancer, birth defects or other
reproductive harm.