Polaris Ranger 500 2x4 2007, Service Manual

Page: 86 / 345

3.27
ENGINE
3
Reaming The Valve Guide
5. Allow cylinder head to cool to room temperature. Apply
cutting oil to the reamer. Guides should be reamed from
the valve spring side of the cylinder head. Ream each guide
to size by turning the reamer clockwise continually.
Continue to rotate reamer clockwise during removal of the
tool.
6. Clean guides thoroughly with hot soapy water and a nylon
brush. Rinse and dry with compressed air. Apply clean
engine oil to guides.
7. Install pilot into valve guide.
8. Apply cutting oil to valve seat and cutter.
9. Place 46
o
cutter on the pilot and make a light cut.
10. 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
o
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 is distorted from improper installation and
must be replaced. Be sure the cylinder head is at the
proper temperature and replace the guide.
• 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.
11. 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
o
) apply black permanent
marker to the entire valve face (A).
12. Insert valve into guide and tap valve lightly into place a few
times.
13. 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.
• If the indicated seat contact is at the top edge of the
valve face and contacts the margin area it is too high on
the valve face. Use the 30
o
cutter to lower the valve
seat.
• If too low use the 60
o
or 75
o
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
o
cutter and
re-check contact point on the valve face and seat width
after each cut.
Valve Seat Width:
Intake Std: .028” (.7 mm)
Limit: .055” (1.4 mm)
Exhaust Std: .039”(1.0 mm)
Limit: .071” (1.8 mm)
A