Compression And Leakdown Tests; Sportsman Silencer Cleaning - Polaris Sportsman 850 Service Manual

MAINTENANCE
22. After tightening the jam nut, turn the rocker arm
bearing with your fingers. If it spins as it did before
contacting the valve, it is too loose. If it cannot be
turned, it is too tight.
If rocker arm bearing does not turn with slight drag, you
will need to perform the adjustment again (see Step
23. Turn the drive clutch counter-clockwise to rotate the
cam sprocket 225° to the PTO Adjustment Position.
24. Repeat steps 20-22.
25. Clean sealing surfaces of the cylinder head and
valve cover.
26. Inspect the condition of the valve cover bolt rubber
isolators. If rubber has become hardened or cracked,
replace them.
27. Install a new valve cover seal and ensure the seal is
fully seated into the groove of the cover.
28. Install the valve cover and torque the cover bolts to
specification.
TORQUE
Valve Cover Bolts:
12-14 ft-lbs (16-19 Nm)
29. Install the upper right-hand frame support and torque
the (4) mounting bolts to specification.
TORQUE
Upper Frame Rail Fasteners:
36 ft. lbs (49 Nm)
30. Reassemble vehicle by reversing this procedure.
2.20
NOTE
20).
31. Torque intake runner mounting bolts to specification.
TORQUE
Plenum to Throttle Body Fasteners:
7 ft-lbs (10 Nm)
32. Start the engine to ensure proper valve adjustment
was performed.

COMPRESSION AND LEAKDOWN TESTS

This engine does NOT have decompression
components. Compression readings will vary in
proportion to cranking speed during the test.
Smooth idle generally indicates good compression. Low
engine compression is rarely a factor in running condition
problems above idle
compression can be caused by worn or damaged
exhaust cam lobes.
A cylinder leak-down test is the best indication of engine
condition. Follow tester manufacturer's instructions to
perform a cylinder leak-down test. (Never use high
pressure leakage testers as crankshaft seals may
dislodge and leak).
Measured Cylinder Compression:
210-250 psi (full throttle)
Cylinder Leakage Service Limit: 10%
(Inspect for cause if leakage exceeds 10%)

SPORTSMAN SILENCER CLEANING

WARNING
Do not perform clean out immediately after the engine
has been run, as the exhaust system becomes very
hot. Serious burns could result from contact with
exhaust components.
To reduce fire hazard, make sure that there are no
combustible materials in the area when purging the
exhaust silencer.
Wear eye protection.
Do not stand behind or in the front of the vehicle while
purging the silencer.
Never run the engine in an enclosed area. Exhaust
contains poisonous carbon monoxide.
Failure to heed these warnings could result in serious
injury or death.
The exhaust silencers must be periodically purged of
accumulated carbon as follows:
NOTE
speed. Abnormally high