Combustion Chamber; Valve Guide Removal / Installation - Polaris 2009 Sportsman XP 850 Service Manual

Combustion Chamber

1. Clean all accumulated carbon deposits from combustion
chamber and valve seat area.
NOTE: Carbon Clean Fuel Treatment (2871326) can
be used to help remove carbon deposits.
IMPORTANT: Do not use a metal scraper, a coarse
wire brush, or abrasive cleaners to clean the cylinder
head. Damage may result.
2. Visually inspect cylinder head gasket surface and
combustion chamber for cracks or damage. Pay close
attention to the areas around spark plug and valve seats.

Valve Guide Removal / Installation

1. Support cylinder head and place valve guide remover into
valve guide from the combustion chamber side.
2. Drive or press old valve guides out of cylinder head.
CAUTION
Replacement of valve guides requires an oven,
special equipment and experience to do the job
correctly. If you are unsure of your ability to do
the repair professionally it is best to sublet the
labor to a competent machinist.
Valve seat reconditioning is required when
valve guides are replaced.
CAUTION
The cylinder head can be easily damaged if the
procedure is done carelessly.
3. Apply 90 weight oil to outside of new valve guides.
4. Drive or press new guides from camshaft side of head to
proper installed height. Note difference between intake and
exhaust guide height below.
Intake Valve Guide Height: 8.93 - 9.43 mm
Exhaust Valve Guide Height: 6.75 - 7.25 mm
5. Ream or hone new valve guides to size to obtain specified
stem-to-guide clearance. Ream from combustion chamber
side of head.
CAUTION
Do not tilt the reamer while reaming the guide. Always
rotate the reamer in a clockwise direction.
6. Clean cylinder head thoroughly with clean solvent.
7. Inspect valve seats and recondition if necessary.
ENGINE
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