Baja WD250U Service Manual page 171

If out of specification, rebore or replace the
cylinder and piston (replace in a set)
• Measure the diameter "P" of piston lower part
with micrometer, (b) is the measuring position
(b) is 4mm away from piston bottom (0.16 in)
Piston lower part diameter "P"
Standard 70.92~70.97mm (2.792~2.794in)
If out of specification, replace the piston and
piston ring as a set at the same time.
•Calculate the mating cylinder clearance with
the following formulas
Mating cylinder clearance="C"-"P"
Inner diameter of cylinder "C"
Piston lower part diameter "P"
Mating cylinder clearance: 0.04~0.06mm
(0.0016~0.0024 in)
Limit:
0.15mm (0.0059 in)
•If out of specification, rebore or replace the
cylinder, and replace the piston and piston ring
as a set at the same time.
15. Piston ring and piston pin
Piston ring
1) Measure
• Clearance between piston ring and ring groove
• Use feeler gauge (1)
If out of specification, replace piston and a set
of rings
CAUTION:
First clean the carbon deposits inside the piston
ring and ring groove, followed by measuring the
clearance between piston ring and ring groove.
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