9850043 R01 - 2017-2021
RANGER
500 / 570 Service Manual
© Copyright Polaris Inc.
3.55
5. To check the contact area of the seat on the valve
face, apply a thin coating of Prussian Blue paste to
the valve seat. If using an interference angle (46°)
apply black permanent marker to the entire valve face
q
.
6. Insert valve into guide and tap valve lightly into place
a few times.
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.
NOTICE
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
e
.
MEASUREMENT
Valve Seat Width:
Intake:
Std.: .0591" (1.50 mm)
Service Limit: .0748" (1.90 mm)
Exhaust:
Std.: .0787” (2.00 mm)
Service Limit: .0945" (2.40 mm)
• If the indicated seat contact is at the top edge of the
valve face and contacts the margin area
w
it is too
high on the valve face. Use the 30° cutter to lower
the valve seat.
• If too low, use the 60° 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.
MEASUREMENT
Intake Seat Cutter Diameter
1.979 in. (50.26 mm)
Exhaust Seat Cutter Diameter
1.617 in. (41.08 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.
NOTICE
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.
CYLINDER REMOVAL
1. Remove and discard the head gasket.
Summary of Contents for RANGER 500 2017
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