Valve Seat Reconditioning - Polaris Ranger 500 2x4 2007 Service Manual

ENGINE

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 instructions
provided in the cylinder head service tool kit.
Wear eye protection when performing cylinder
head service. Valve guide replacement will
require heating of the cylinder head.
Wear gloves to prevent burns.
Valve Guide Removal / Installation
1. Remove all carbon deposits from the combustion chamber,
valve seat and valve guide area before attempting to
remove valve guides. CAUTION: Carbon deposits are
extremely abrasive and may damage the valve guide bore
when guides are removed.
2. Place new valve guides in a freezer for at least 15 minutes
while heating cylinder head.
3. Heat cylinder head in an oven or use a hot plate to bring
cylinder head temperature to 212° F (100° C).
CAUTION: Do not use a torch to heat cylinder head or
warpage may result from uneven heating.
temperature can be checked with a pyrometer or a welding
temperature stick.
Follow the manufacturers instructions provided with the valve
seat cutters in the Valve Seat Reconditioning Kit (PN 2200634).
Abrasive stone seat reconditioning equipment can also be used.
Keep all valves in order with their respective seat.
Too Uneven
Wide
3.26
CAUTION
Good Too
Narrow
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.
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 burnt valves.
1. When thoroughly heated, place cylinder head on blocks of
wood which will allow the old guides to be removed.
2. Using valve guide driver, drive guides out of the cylinder
head from the combustion chamber side. Be careful not to
damage guide bore or valve seat when removing guides.
3. Place cylinder head on cylinder head table.
NOTE: Be sure cylinder head is still at 212° F
(100° C) before installing new guides.
4. Place a new guide in the valve guide installation tool and
press guide in to proper depth. Check height of each guide
above the cylinder head (A).
Valve Guide Installed Height
Head
.689 - .709" (17.5 - 18.0 mm)
NOTE: The guide can also be driven in to the proper
depth. Inspect the guide closely for cracks or
damage if a driver is used.
If the seat is
Valve Guide Height: