Polaris RANGER ETX 2015 Owner's Manual page 146

ENGINE / COOLING SYSTEM
7. Remove valve and check where the Prussian Blue
indicates seat contact on the valve face. The valve
seat should contact the middle of the valve face or
slightly above, and must be the proper width.
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).
MEASUREMENT
Valve Seat Width:
Std.: .0393" (1.00 mm)
Service Limit: .0551" (1.4 mm)
Exhaust:
Std.: .0393" (1.00 mm)
Service Limit: .0758" (1.9 mm)
* If the indicated seat contact is at the top edge of the
valve face and contacts the margin area (B) it is too
high on the valve face. Use the 30° cutter to lower
the valve seat.
* If too low, use the 70° cutter to raise the seat. When
contact area is centered on the valve face, measure
seat width.
* If the seat is too wide or uneven, use both top and
bottom cutters to narrow the seat.
* If the seat is too narrow, widen using the 45° cutter
and re-check contact point on the valve face and
seat width after each cut.
3.54
NOTE
Intake:
9926806 R03 - 2015 - 2016 RANGER ETX / 570 2-SEAT 2015 - 2016 RANGER 570 CREW Service Manual
Intake Seat Cutter Diameter:
1.172 in. (29.793 mm)
8. Clean all filings from the area with hot soapy water.
Rinse and dry with compressed air.
9. Lubricate valve guides with clean engine oil and
apply oil or water based lapping compound to the
face of the valve.
Lapping is 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 valves.
12. Thoroughly clean cylinder head and valves.
Valve Seat Angles
1 - 17°
2 - 45°
3 - 70°
Exhaust Seat Cutter
Diameter:
0.956 in. (24.294 mm)
NOTE
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