oily sparkplug

[temeluchus]

After a long run on the motorway, I slowed down to stop at a set of lights and the bike started to misfire badly.

Pulling away it misfired even worse, then picked up and cleared out once the revs raised a bit-not exactly sure what rpm as i dont have a rev counter. It repeted this when idling or very small throttle openings/low rpm.

getting the contraption home, inspection of the carbs didnt seem to show any issues. Also checked the coils-ht leads and caps seemed fine. Stuffed the bare ends of the HT leads to the sparkplugs, same issue. tried my spare coil, same again.

Pulled the plugs and the right hand plug is covered in oil.........put in a spare plug and started the bike. Ran it up and the same misfire. Removed the plug and its now covered in oil.

Evidently I have a leak somewheres.

Well I think I either have a failed oil control ring (the motor seems to be fine at speed so the compression rings seem ok dont have my comp tester to hand...) or a leaky valve guide. Crankcase breather seems to be fine-is certainly venting as I can feel the output on my hand.

Anyone have any other ideas?

Ah well spanners out tomorrow just as well i have a spare head barrel and piston...
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Some shite cruiser. Now with guns and FREEDOM!

[Dr. DaveJPS]

what does the other spark plug look like?
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"intelligent inattention is preferable to unintelligent tinkering"
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[temeluchus]

[Dr. DaveJPS]

ah ok, i thought it might be ignition timing cause i'm having the problem where one cylinder is retarded and the other is advanced. that has similar symptoms
____________________
"intelligent inattention is preferable to unintelligent tinkering"
www.davejps.com

[temeluchus]

The motor has one contact breaker and a twin output coil-if timing was off i guess it would be off on both?

deffo oil, right hand plug is covered in baked on sludge.
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Some shite cruiser. Now with guns and FREEDOM!

[the grim reaper]

I would have thought that an oil ring failure would be a bit more noticeable, to be sure, I'd drain the oil and sieve it as it comes out. If that is clean, it could be that your head gasket has gone, from an oilway into the combustion chamber.

Cheers

Grim
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[temeluchus]

Aye it is possible.

Post mortem tomorrow- Spare barrel piston etc to go on with a nice new set of gaskets....

If the oil ring has gone itll be sump off time as well lol
____________________
Some shite cruiser. Now with guns and FREEDOM!