4. Maintenance
USE AND MAINTENANCE MANUAL
CHAPTER 4
MAINTENANCE
4-Strokes - Edition 00 / 2022
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4
A
B
Piston check
– Measure the outside diameter of piston “A” in measuring
position “B” using the micrometer.
Piston diameter (XXF 250 / XEF 250):
76.955 – 76.970mm (3.0297 – 3.0303 in)
Measuring point “B” (from the lower side of the
piston skirt) (XXF 250 / XEF 250): 4.0mm (0.16 in)
Piston diameter (XXF 450 / XEF 450):
96.955 – 96.970mm (3.8171 – 3.8177 in)
Measuring point “B” (from the lower side of the
piston skirt) (XXF 450 / XEF 450):
9.0mm (0.35 in)
If the diameter does not comply with the specifications,
replace the cylinder, piston and segments all together.
– Finally, calculate the clearance between cylinder and piston:
Clearance = Cylinder “C” bore - Piston diameter
Clearance between piston and cylinder
(XXF 250 / XEF 250):
0.030 – 0.055mm (0.0012 – 0.0022 in)
Clearance between piston and cylinder
(XXF 450 / XEF 450):
0.010 – 0.045mm (0.0004 – 0.0018 in)