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ENGINE
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9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
4. Measure free length of spring with a Vernier caliper.
Check spring for squareness. Compare to
specifications. Replace spring if either measurement
is out of specification.
5. Remove valve seals.
CAUTION: Replace seals whenever the cylinder
head is disassembled. Hardened, cracked or worn
valve seals will cause excessive oil consumption and
carbon buildup.
Valve Inspection
1. Remove all carbon from valve with a soft wire wheel.
2. Check valve face for runout, pitting, and burnt spots.
To check for bent valve stems, mount valve in a drill
or use “V” blocks and a dial indicator.
3. Check end of valve stem for flaring, pitting, wear or
damage (A).
4. Inspect split keeper groove for wear or flaring of the
keeper seat area (B).
NOTE: The valves cannot be re-faced or end ground.
They must be replaced if worn, bent, or damaged.
5. Measure diameter of valve stem with a micrometer in
three places and in two different directions (six
measurements total). Compare to specifications.
6. Measure valve guide inside diameter at the top middle
and end of the guide using a small hole gauge and a
micrometer. Measure in two directions, front to back
and side to side.
7. Subtract valve stem measurement to obtain stem to
guide clearance.
NOTE: Be sure to measure each guide and valve
combination individually.
8. Replace valve and/or guide if clearance is excessive.
Compare to specifications.
Valve Stem Diameter:
Intake: .2343-.2348” (5.950-5.965 mm)
Exhaust: .2341-.2346” (5.945-5.960 mm)
Valve Guide I.D.:
.2362 - .2367” (6.0 - 6.012 mm)
Measure valve stem in
several places
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