
Cylinder and piston | 6 |
Larger, harder particles that enter the engine cause serious damage to the under- side of the piston skirt.
Cause: | Action: | |
• | Air filter damaged or missing. | Fit a new air filter. |
• | Parts from the carburettor or intake | Regular service and inspection. |
| system have come loose and |
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| entered the engine. |
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Extensive damage to the lower part of the piston’s inlet side.
Service tips |
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Defect: |
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Broken cooling fins, damaged threads or sheared bolts by |
| In severe cases – replace the cylinder. | |
the exhaust port. |
| Repair the threads using | |
Seizure marks in the cylinder bore (especially by the |
| Polish the damaged area using a fine grade emery cloth | |
exhaust port). |
| so that the coating of aluminium disappears. | |
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| With deep seizure score marks the piston and cylinder | |
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| should be replaced. | |
Surface coating in the cylinder bore worn out (primarily at |
| Replace the cylinder and piston. | |
the top of the cylinder). |
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The piston shows signs of seizure score marks. |
| Carefully polish the damaged area using a fine file of fine | |
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| grade emery cloth. Before the piston is refitted the cylinder | |
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| should be polished as above. With deep score marks the | |
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| piston and cylinder should be replaced. | |
Piston ring burnt in its groove. |
| Carefully loosen the piston rings and clean the groove well | |
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| before refitting. Carbon deposits in the groove impair the | |
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| important heat transfer between the piston and cylinder. | |
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| NOTE! |
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| Be careful with the lower edge of the piston ring |
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| groove. If this is damaged, or if carbon deposits |
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| remain, the compression pressure can leak through. |
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| Check the wear on the piston ring by placing it in the lower | ||
| part of the cylinder. | ||
Bolts much too tight in the aluminium material. | Position a suitable punch on the bolt head and give a few | ||
| sharp knocks with a hammer. If the bolt still does not loosen, | ||
| repeat the procedure. | ||
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