Combustion Chamber; Valve Seat Inspection; Cylinder Head Reconditioning; Valve Guide Removal/Installation - Polaris Magnum 2x4 Service Manual

Engine Disassembly, Cont.
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.
Combustion Chamber
Clean all accumulated carbon deposits from combustion
chamber and valve seat area with a soft wire brush.
Valve Seat Inspection
ENGINE
EH42PL/EH50PL Engine
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. See Valve Seat Reconditioning, page 3.56. 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 recondi-
tioning techniques. Follow the instructions provided in the cylinder head service tool kit.
CAUTION:
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
0
F (100
0
C).
CAUTION:
Do not use a torch to heat cylinder head or warpage may result from uneven heating. Head
temperature can be checked with a pyrometer or a welding temperature stick.
4. When thoroughly heated, place cylinder head on blocks of wood which will allow the old guides to be removed.
5. 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.
Polaris Industries Inc.
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