Compression Test; Engine Mounts - Polaris Sportsman 400 Service Manual

MAINTENANCE

COMPRESSION TEST

NOTE: 4-Stroke engines are equipped with an automatic decompressor. Compression readings will vary in pro-
portion to cranking speed during the test. Average compression (measured) is about 50-90 psi during a compres-
sion test.
Smooth idle generally indicates good compression. Low engine compression is rarely a factor in running condition
problems above idle speed. Abnormally high compression can be caused by a decompressor malfunction, or
worn or damaged exhaust cam lobes. Inspect camshaft and automatic decompression mechanism if compres-
sion is abnormally high.
A cylinder leakage test is the best indication of engine condition on models with automatic decompression. Follow
manufacturer's instructions to perform a cylinder leakage test. (Never use high pressure leakage tester as crank-
shaft seals may dislodge and leak).
Cylinder Compression
Standard
Cylinder Leakage
Service Limit
(Inspect for cause if leakage exceeds 10%)

ENGINE MOUNTS

Inspect rubber engine mounts (A) for cracks or damage.
FASTENER TORQUE - ENGINE
Check engine fasteners and ensure they are tight.
2.18
- projex@inbox.lv -
50-90 PSI
10 %
A
A
A