Polaris 2000 120 XCR Rider's Safety Manual And Owner's Operation And Maintenance Manual page 57

Spark Plug Selection
Original equipment parts or their equivalent should always be used. However, the
heat range of spark plugs is of utmost importance. A spark plug with a heat range
which is too high will cause engine damage. A spark plug with a heat range which
is too low will cause excessive fouling and malfunction.
In selecting a spark plug heat range for production, a manufacturer is forced to as-
sume that the engine is going to operated under extreme heavy duty conditions.
This protects the engine from internal damage in the event that the purchaser actu-
ally does operate the engine in this manner. This selection however, could cause
the customer who normally operates the engine under medium or light duty to have
spark plug failure. Refer to your Owner's Manual Supplement for the specific spark
plug to be used in your machine.
A plug with a heat range which is too high will always cause engine damage
if the engine is operated in conditions more severe than that for which the
spark plug was intended.
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.
D Use recommended spark plugs
D Proper electrode gap is .025"/0.635mm
D 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
D 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 depos-
its. 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.
CAUTION
MAINTENANCE
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