Polaris 120 XC SP - Manual (Page 61)

A--42
MAINTENANCE
Spark Plug Selection
A new engine can cause temporary spark plug fouling even though the
heat range is proper, due to the preservative which has been added
during assembly of the engine to combat rust and corrosion. Avoid
prolonged idle speeds, as plug fouling and carbonization will result.
S
Use recommended spark plugs
S
Proper electrode gap is .025,/0.635mm
S
Spark plug torque is 18 ft. lbs. (2.5 kg/m) for used plugs and 11 ft. lbs.
(1.52 kg/m) for new plugs
S
Always carry spare spark plugs
NOTE: Incorrect fuel mixture can often cause a spark plug to appear to
be too dark or too light in color. Before changing spark plug heat ranges,
be sure the correct main jet is installed in the carburetor(s).
The spark plug and its condition is indicative of engine operation. The
spark plug firing end condition should be read after the engine is
warmed up and the vehicle is driven at higher speeds. Immediately
check the spark plug for correct color.
Normal
The insulator tip is gray, tan, or light brown. There will be a few
combustion deposits. The electrodes are not burned or eroded. This
indicates the proper type and heat range for the engine and the service.
NOTE: The tip should not be white. A white insulator tip indicates
overheating, caused by use of an improper spark plug or incorrect
carburetion adjustments.