Checking The Crankcase; Checking The Piston Pins; Checking The Piston Rings - Yamaha MX800V Service Manual

PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
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a

CHECKING THE CRANKCASE

1.
Check:
• Crankcase
Damage  Replace.
• Bearing
Noise/wear/rotational failure  Replace.

CHECKING THE PISTON PINS

The following procedure applies to all of the piston pins.
1.
Check:
• Piston pin
Blue discoloration/grooves  Replace the piston
pin and then check the lubrication system.
2.
Measure:
• Piston pin hole inside diameter "a"
Out of specifications  Replace.
Piston pin hole inside diameter:
Limit:
3.
Measure:
• Piston pin diameter "a"
Out of specification  Replace.
Piston pin diameter:
Limit:
a
4.
Check:
• Check that the piston pin enters smoothly into the
piston pin hole.
TIP
If the piston pin fits too tight into the piston, check the pis-
ton pin hole. If there is any protrusion, use a knife or
scraper to gently remove it so that piston pin can be
pushed in smoothly with your fingers.

CHECKING THE PISTON RINGS

The following procedure applies to all of the piston rings.
3-48
19.004–19.015 mm (0.7482–0.7486 in)
19.045 mm (0.7498 in)
18.995–19.000 mm (0.7478–0.7480 in)
18.975 mm (0.7470 in)