TOHATSU EverRun MX 18E2 Service Manual page 206

Power Unit
a
5-54
b
22) Inspection of Pistons
1. Inspection of Piston Outer Diameter
Measure piston outer diameter, and replace the piston if
the outer diameter is less than the functional Limit.
Measurement Point b :
12 mm (0.47 in) above bottom end of piston skirt.
approximately 90 degrees from pin hole.
Standard Value a :
Standard Piston :
59.95 - 59.97 mm (2.360 - 2.361 in)
Oversized Piston :
60.45 - 60.47 mm (2.380 - 2.381 in)
Functional Limit a :
Standard Piston : 59.90 mm (2.358 in)
Oversized Piston : 60.40 mm (2.378 in)
2. Inspection of Piston Clearance
Calculate piston clearance, and if it is over the limit,
replace piston or any of piston rings, replace cylinder, or
use oversized piston.
Piston Clearance :
Standard Value :
0.05 - 0.09 mm (0.00197 - 0.00354 in)
Functional Limit :
0.15 mm (0.00591 in)
Calculation of Piston Clearance :
Cylinder Inner Diameter - Piston Outer
Diameter
Use the maximum value of the cylinder inner
diameter measured.
3. Inspection of Piston Rings
1) Push a piston ring into the cylinder by using top surface
of a piston.
2) Use thickness gauge to measure piston ring gap.
Replace piston ring if the gap is over specified value.
Thickness Gauge :
Commercially Available Item
Piston Ring End Gap : Standard Value
0.20 - 0.40 mm (0.00787 - 0.01575 in)
Functional Limit :
0.50 mm (0.01969 in)
GB
2st X18E2 2012