Article about Lucas 2MC capacitor

sole survivor said:

I have a question about this blue capacitor. My 1970 Fastback refuses to start despite the fact the the valves have been adjusted, the Trispark is delivering a really big spark; the timing is spot on the carbs are balanced, installed a new alternator and my battery is always on a battery tender. Can the capacitor prevent the bike from starting for any reason?

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Try disconnecting the 2MC's earth/ground (red) wire and see if that makes any difference?

sole survivor said:

Can the capacitor prevent the bike from starting for any reason?

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Yes, it can, for various reasons. I'm not sure what you have in your system, but the MC2 is not required to run the ignition. To point, I thought after rebuilding my bike, I would start it like I used to without the battery and using the MC2 Cap. No way. I finally hooked up a battery and it started right up. It doesn't take much of a battery to get it going either. 2-4AH will do, but for daily running a 8AH will do fine with the capacitor gone. Depends on how good your charging system is working. After 30 years, the magnetism in the rotor is pretty much weakened.

Dave
69S

testing and "reforming" capacitors

this is a good page on how to do it....big electrolytic capacitors similar to the Lucas 2MC are common in old tube/valve gear and can sometimes be saved after sitting for years by bringing them up to working voltage slowly

broken link removed