Polaris 2014 Sportsman 570 EF Service Manual page 106

ENGINE
Renewing Valve Seats
1. Install pilot into valve guide.
2. Apply cutting oil to valve seat and cutter.
3. Place 46° cutter on the pilot and make a light cut.
4. Inspect the cut area of the seat:
* If the contact area is less than 75% of the
circumference of the seat, rotate the pilot 180° and
make another light cut.
* If the cutter now contacts the uncut portion of the
seat, check the pilot. Look for burrs, nicks, or runout.
If the pilot is bent it must be replaced.
* If the contact area of the cutter is in the same place,
the valve guide
installation.
* If the contact area of the initial cut is greater than
75%, continue to cut the seat until all pits are
removed and a new seat surface is evident.
NOTE: Remove only the amount of material
necessary to repair the seat surface.
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 (A).
6. Insert valve into guide and tap valve lightly into place
a few times.
3.48
is distorted from improper
9924871 R03 - 2014 Polaris Sportsman® 570 EFI Service Manual
© Copyright 2013 Polaris Sales Inc.
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.
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).
Valve Seat Width:
Intake:
Std.: .0393" (1.00 mm)
Service Limit: .0551" (1.4 mm)
Exhaust:
Std.: .0590" (1.50 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 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.