Polaris Sportsman 400 User Manual

MAINTENANCE
2.18
COMPRESSION TEST
NOTE: 4-Stroke engines are equipped with anautomatic decompressor. Compressionreadings willvary inpro-
portiontocrankingspeedduring thetest. Averagecompression(measured)is about50-90 psiduringacompres-
sion t est.
Smoothidlegenerallyindicatesgoodcompression. Lowenginecompressionisrarelyafactorinrunningcondition
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.
Acylinderleakagetestisthebestindicationofengine conditiononmodelswithautomaticdecompression. Follow
manufacturer’sinstructions toperform acylinderleakagetest. (Never usehighpressureleakagetesterascrank-
shaft seals may dislodge and leak).
ENGINE MOUNTS
Inspect rubber engine mounts (A) for cracks or damage.
FASTENER TORQUE - ENGINE
Check engine fasteners and ensure they are tight.
Cylinder Compression
Standard 50-90 PSI
Cylinder Leakage
Service Limit 10 %
(Inspect for cause if leakage exceeds 10%)
A
A
A

Polaris Sportsman 400 Specifications

General

Brand	Polaris
Model	Sportsman 400
Category	Offroad Vehicle
Language	English