Polaris 2009 Sportsman XP 850 Service Manual page 125

NOTE: When using an interference angle, the seat
contact point on the valve will be very narrow, and is
a normal condition. Look for an even and continuous
contact point all the way around the valve face (A).
Bottom 60° Seat 45°
Valve Seat Width:
Intake Std: .028" (.7 mm)
Limit: .055" (1.4 mm)
Exhaust Std: .039I (1.0 mm)
Limit: .071" (1.8 mm)
B
A
Proper Seat Contact
on Valve Face
Top 30°
Seat
Width
= In. / mm.
8. Clean all filings from the area with hot soapy water. Rinse
and dry with compressed air.
9. Lubricate the valve guides with clean engine oil, and apply
oil or water based lapping compound to the face of the
valve.
NOTE: Lapping not required if an interference angle
reconditioning method is used.
10. Insert the valve into its respective guide and lap using a
lapping tool or a section of fuel line connected to the valve
stem.
11. Rotate the valve rapidly back and forth until the cut sounds
smooth. Lift the valve slightly off of the seat, rotate 1/4
turn, and repeat the lapping process. Do this four to five
times until the valve is fully seated, and repeat process for
the other valve(s).
12. Thoroughly clean cylinder head and valves.
ENGINE
5
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