Cylinder and piston | 6 |
Use a new gasket and fit the cylinder.
Make sure that the inlet manifold is correctly connected to the sleeve coupling on the cylinder and that the impulse nipple sits right.
502 50 70-01
Screw the cylinder into place and tighten the clamp around the inlet manifold.
Assemble the other parts.
Place a new cylinder pedestal gasket on the cylinder.
Lubricate the piston and the inlet manifold on the cylinder with a few drops of engine oil and fit the cylinder using the smallest piston ring compres- sor in assembly kit 502 50
Make sure that the inlet manifold is correctly connected to the sleeve coupling on the cylinder and that the impulse nipple sits right.
Screw the cylinder into place.
Tighten the clamp around the inlet manifold.
Assemble the carburettor and the other parts in the reverse order as set out for dismantling.
Small to medium size scores primarily in the middle of the exhaust port.
Analysis and actions
Experience tells us that piston or cylinder failure due to manufacturing errors are extremely rare.
The reason is usually due to other factors, which is evident from the following.
Note the reasons for the breakdown, repair the damage and take the actions required to prevent the same thing happening again.
Insufficient lubrication
The piston has small to medium size score marks usually in front of the exhaust port. In extreme cases heat development can be so great that material from the piston smears along the piston skirt and even in the cylinder bore.
Generally the piston ring is undamaged and moves freely in the ring groove
There can also be scores on the inlet side of the piston.
Cause: | Action: |
• Incorrect carburettor setting. | Check and change the carburettor |
Recommended max. speed ex- | setting. |
ceeded. |
|
• Incorrect oil mixture in the fuel. | Change the fuel. |
• Too low octane fuel. | Change to a higher octane petrol. |
|
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