Polaris R09VA17AA, Service Manual

Page: 63 / 187

3.19
ENGINE
3
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.
NOTE: If valve guides are replaced, valve seats must
be reconditioned. Refer to Valve Seat
Reconditioning for procedure.
Valve Seat Reconditioning
Valve Seat Inspection
Inspect valve seat in cylinder head for pitting, burnt spots,
roughness, and uneven surface. If any of the above conditions
exist, the valve seat must be reconditioned. If the valve seat is
cracked the cylinder head must be replaced.
Cylinder Head Reconditioning
NOTE: Servicing the valve guides and valve seats
requires special tools and a thorough knowledge of
reconditioning techniques.
Follow the manufacturers instructions provided with the valve
cutting kit (commercially available). Abrasive stone seat
reconditioning equipment can also be used. Keep valves in order
with their respective seat.
NOTE: Valve seat width and point of contact on the
valve face is very important for proper sealing. The
valve must contact the valve seat over the entire
circumference of the seat, and the seat must be the
proper width all the way around. If the seat is
uneven, compression leakage will result. If the seat
is too wide, seat pressure is reduced, causing
carbon accumulation and possible compression
loss. If the seat is too narrow, heat transfer from
valve to seat is reduced and the valve may overheat
and warp, resulting in burned valves.
1. Install pilot into valve guide.
2. Apply cutting oil to valve seat and cutter.
Too
Wide
Uneven
Good Too
Narrow
CAUTION
Wear eye protection when
performing cylinder head service.
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