27-08-13, 10:50 PM
Well, you were right. My '3M' (mechanically-minded mate) came over for a pint and fish'n'chips and as soon as we turned it over he said it's lack of compression due to dry bores. He reckoned that the rings can get stuck in their compressed state as the pistons cool after a long run and the oil drains down, especially if there's a little bit of carbon making them tight in their grooves. That can be enough to lower the compression to the point of no starting.
The 'quick fix' that worked for us was just to hook it up to my car and jump it. Once I revved up the car to the point it was kicking out decent amperage the bike caught. Jeff reckoned this is quite common but a bike battery, even fully charged, can't do it. He said turning the engine over fast enough draws oil up from the sump and also can generate enough heat and vibration to help the sticky rings pop out again and restore full compression.
Anyway, whatever the intimate details, seems that solved it! Thank goodness it wasn't the starter clutch, I was fooled by the speed at which it was turning over. You live and learn. Gotta love forums and the guys who share their knowledge.
The 'quick fix' that worked for us was just to hook it up to my car and jump it. Once I revved up the car to the point it was kicking out decent amperage the bike caught. Jeff reckoned this is quite common but a bike battery, even fully charged, can't do it. He said turning the engine over fast enough draws oil up from the sump and also can generate enough heat and vibration to help the sticky rings pop out again and restore full compression.
Anyway, whatever the intimate details, seems that solved it! Thank goodness it wasn't the starter clutch, I was fooled by the speed at which it was turning over. You live and learn. Gotta love forums and the guys who share their knowledge.
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There's no replacement for displacement
There's no replacement for displacement