(27-07-14, 10:19 PM)PieEater link Wrote: I think the ends of the HT leads can get brittle with heat and age and then engine vibes can then loosen them off so they don't make as good contact with the plug cap connector. I keep meaning to do mine.
Close to the mark Pie eater, but what happens is that the end of the leads soften due to heat and lose shape, the wire in the lead can corrode due to water ingress and the connection goes high resistance killing the spark and yes the engine vise cause them to loosen off. Reason I know is that I spent part of the day sorting the original plug caps of a 600.
Stripped and cleaned the connection inside them including the small washer which can break in half and spring ends. Broke open a few old NGK ones I had hanging around and used the resistors from them as they are better than the originals and do not require the small washers (NGK are 5K Ohm and seem to vary by 5% whereas the OEM are 10K Ohm, but vary by 20%. I trimmed 10mm of the end of the lead and cut open the trimmed bit, the wire was corroded but the lead was out of shape and softer than the rest of the lead.
I was messing with the old screws from the NGK caps I broke and they were quite loose in the pieces I had cut off
Bike running sweetly now at all revs [img alt=
]http://foc-u.co.uk/Smileys/efocicon/smile.gif[/img]Unlikely to be water as it would effect starting more than running, but will do no harm to drain the carbs anyway just to be on the safe side, might be dirt in there