Polaris TRAIL BOSS 325 2001, Manual

Page: 92 / 296

ENGINE
3.36
PISTON INSPECTION, CONT.
6. Measure piston ring to groove clearance by
placing the ring in the ring land and measuring with
a thickness gauge. Replace piston and rings if
ring-to-groove clearance exceeds service limits.
PISTON RING INSTALLED GAP
1. Place each piston ring inside cylinder using piston
to push ring squarely into place as shown at right.
2. Measure installed gap with a feeler gauge at both
the top and bottom of the cylinder.
NOTE: A
difference in end gap indicates cylinder taper. The
cylinder should be measured for excessive taper
and out of round.
3. If the bottom installed gap measurement exceeds
the service limit, replace the rings.
NOTE: Always check piston ring installed gap after re-
boring a cylinder or when installing new rings. A re-
bored cylinder should always be scrubbed thoroughly
with hot soapy water, rinsed, and dried completely.
Wipe cylinder bore with an oil rag immediately to re-
move residue and prevent rust.
Piston
Ring
Feeler Gauge
Ring to groove clearance
Piston Ring-to-Groove Clearance
Top Ring Std: .0014-.0030
I
(.035-.075 mm)
Limit: .0059
I
(.15 mm)
Second Ring Std: .0010-.0026
I
(.025-.065 mm)
Limit: .0059
I
(.15 mm)
25-50mm
Cylinder
Piston Ring
Feeler Gauge
Piston ring end gap installed
Piston Ring Installed Gap
Top Ring
Std: .0079-.0138
I
(.20-.36 mm)
Limit: .039
I
(1.0 mm)
Second Ring
Std: .0138-.0197
I
(.35-.50 mm)
Limit: .039
I
(1.0 mm)
Oil Ring
Std: .0079-.0276
I
(.20-.70 mm)
Limit: .059
I
(1.5 mm)