2008 Sportsman 500 Service Manual Chapter 3

ENGINE

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 seat area (B). NOTE: The valves cannot be re-faced or end ground. Valves must be replaced if worn, bent, or damaged.

Measure valve stem in several places

Valve Stem Diameter:

Intake: .2343-.2348” (5.950-5.965 mm)

Exhaust: .2341-.2346” (5.945-5.960 mm)

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.

5.

Measure diameter of valve stem with a micrometer in three places and in two different directions (six measurements total). Compare to specifications.

Valve Guide I.D.:

.2362-.2367” (6.0-6.012 mm)

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 use a dial indicator.

A

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.

NOTE: If valve guides are replaced, valve seats must be reconditioned. Refer to Valve Seat Reconditioning for procedure.

B

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

3.22