Engine Mechanical: Piston Ring Free End Gap and Piston Ring End Gap Measure the piston ring free end gap using vernier calipers. Next, fit the piston ring squarely into the cylinder and measure the piston ring end gap using the thickness gauge. If any of the measurements exceed the service limit, replace the piston ring with a new one.
1D-56
(A) (B)
Special tool (A): 09900–20101 (Vernier calipers (1/15 mm, 150 mm))
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Measure the piston pin outside diameter at three positions using the micrometer. If any of the measurements are out of specification, replace the piston pin.
Piston ring free end gap Service limit: (1st): 8.8 mm (0.35 in) Service limit: (2nd): 8.8 mm (0.35 in) Special tool (B): 09900–20803 (Thickness gauge)
Special tool (C): 09900–20205 (Micrometer (0 – 25 mm))
Piston ring end gap Service limit: (1st): 0.50 mm (0.020 in) Service limit: (2nd): 0.50 mm (0.020 in)
Piston pin O.D. Service limit: 21.980 mm (0.8654 in)
(C)
(A)
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Engine Bottom Side Disassembly
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Refer to “Engine Assembly Removal (Page 1D-20)”. Refer to “Engine Top Side Disassembly (Page 1D-27)”.
(B)
NOTE The crankcase must be separated to service the crankshaft and conrod. Starter Motor Remove the starter motor (1). I940H1140170-01
Piston Pin / Pin Bore Measure the piston pin bore inside diameter using the small bore gauge. If measurement is out of specification, replace the piston. Special tool (A): 09900–20602 (Dial gauge (1/1000 mm, 1 mm)) (B): 09900–22403 (Small bore gauge (18 – 35 mm)) Piston pin bore I.D. Service limit: 22.030 mm (0.8673 in)
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