S1 Publishing(Oxford)©20-07

World of motorcycleS
S1 Publishing(Oxford)© 1999-07
 Maintenance - Engines
Pistons

This is just a general guide.
If you are about to do your own maintenance, using these pages, I take no responsibility if you get things wrong!

What do I look for when checking pistons?:
1, Check the top of the piston and see if it is carbonized, if so de-coke it.

2, Check to see if the top ("crown") is damaged.
 On this piston there is a small piece missing and broken, and there is a lot of carbonizing, Probaly caused by running the engine with broken rings.

3, Check the sides and the grooves where the rings fit, also make sure there are no bits of grit blocking the oil wholes in the lowest groove.
although this piston is dirty and old, it would be usable when clean. the wear is normal in an 20yr old engine
The side of this piston as severely damaged, you can see theat the rings have broken, and the small pieces of broken rings have found there way through the top of the piston, and have got into the combestion chamber, on there way the ripped lots of small but deep grooves through the bore, and got jammed into the valves, damaging the seats and the valves. If this happens to you, you are looking at a heafty bill just for parts.
Modified for 2009
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