Article about Lucas 2MC capacitor

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Its quite correct to say the British motorcycle industry had pretty low standards when it came to anything that was vaguely related to precision or accuracy. However when you take on board the fact that a fair amount of the machine tools they were forced to use were very badly worn, with some dating back to before the war, it was quite an achievement for them to hang on as long as they did, bearing in mind it would have been quite impossible for them to have actually made a power unit comparable to anything like the CB750 or ZI.
 
ludwig said:
Because of this thread , and out of curiousity , I loaded up all the electrolitic capacitors I have lying around a few days ago, using a car battery and a test bulb ,ranging fron 4800 to 14000 Mf ... I just checked them , and ALL show at least 11Volts , except one of the 2MC 's ...
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A practical test of a theory! Very good, but a Norton (even a highly improved one) is still a very poor capacitor tester...
 
I consider the 2MC somewhat like a human appendix. Everyone came with one, not necessary and damn sure can cause trouble.
 
ludwig said:
I believe the comparison with an oil leaking engine is valid .
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I really can't agree. Comparing an oil leak to a capacitor discharging seems illogical to me.

ludwig said:
By raisng the bar , I mean we don't have to accept the sloppy tolerances of the British industry of the sixties any more .
We all know where it brought them ..
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Yes, they went the same way that hundreds of other motorcycle factories around the world had already gone before them!
 
Maybe I could incorporate this BFC in the system? Can we end this discussion?

Article about Lucas 2MC capacitor


Dave
69S
 
DogT said:
Maybe I could incorporate this BFC in the system? Can we end this discussion?

Dave
69S
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If I'm reading the labeling correctly, that one appears to be 61,000 microfarads, which is about 10x what you need. See ludwig's post way back on page 1 or so. But if it fits on the bike, what the heck. Go for it! :D

Disclaimer: I changed my major from Electrical Engineering to Computer Science after the first two years and haven't done much with my electronics training since then. So I suppose my opinions are just that - opinions. :mrgreen:
 
DogT said:
Maybe I could incorporate this BFC in the system? Can we end this discussion?
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Why end it? It's just getting good, and it's only 4 pages long!
 
grandpaul said:
Why end it? It's just getting good, and it's only 4 pages long!
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I'm tired and capacitor discussion only lasts so long. Good grief capacitors are capacitors, it's a non-issue. I'd rather talk about rotor magnetism.

Plus I only paid a buck or 2 for that .061F cap at a Hamfest, not $200 for the audio cap.

Dog
 
L.A.B. said:
illf8ed said:
It's been 4 days now since I disconnected the 2MC blue can. It still has 12.4v output. At what point should I make the judgement as good or bad?
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According to the test data given in the factory workshop manuals you could have made that judgement 3 days 23 hours and 55 minutes ago. :wink:
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Cool, no need to replace it. So, 40 years and still ticking. :D
 
illf8ed said:
Cool, no need to replace it. So, 40 years and still ticking. :D
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Isn't that amazing? I have the original one on my 72 750 also, still doing fine after all these years. :D

Debby
 
DogT said:
Maybe I could incorporate this BFC in the system? Can we end this discussion?

Article about Lucas 2MC capacitor


Dave
69S
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you post a photo of a monstrous capacitor and then want to end the thread ?!?! :wink: but seriously, it would take waaay too many kicks to charge it up
 
bluto said:
you post a photo of a monstrous capacitor and then want to end the thread ?!?! :wink: but seriously, it would take waaay too many kicks to charge it up
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With the load that's on it, either the EI or the points, it will never charge until the engine starts running.

Dave
69S
 
I have purchased today a Paradigm 5600 microfarad 50 V. Capacitor. It has 2 small terminals coming out of it.Will this work in the commando battery circuit to replace the old stock 2MC and if so which wires to hook it up to as the stock arrangement has 3 connection points. At present I have disconnected the red wire as suggested. Another approach is to run on battery only,removing the 2MC entirely ,would I have to make a short little wire shunt to complete the circuit between the brown-blue wires of the 2 remaining Cap leads in order to throw it away ?
 
2 of the old MC2 connections are actually the same point (-), so indeed there are 3 points, but only 2 are used (1 plus and 1 of the 2 minus) as I remember.

Dave
69S
 
Torontonian said:
the stock arrangement has 3 connection points.
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There are three terminals, however there are two common male spade terminals on the negative side of the original 2MC which act as a junction for the brown/blue wires-so you would need to connect both brown/blue wires together and also make a connection to the single negative terminal of the new capacitor.

Torontonian said:
Another approach is to run on battery only,removing the 2MC entirely ,would I have to make a short little wire shunt to complete the circuit between the brown-blue wires of the 2 remaining Cap leads in order to throw it away ?
Click to expand...

Whatever you decide, the two brown/blue wires do need to be connected-otherwise no power will reach the ignition switch.
 
Thanks Dave , L.A.B. , Seeing as there are no neg. or pos. indications on the new 5600 30V Cap.(perhaps the thing is not polarity conscious like say my wonderfull warm electric vest) , I am leaning towards the shunt wire between both brown -blue wires to make it all happen without any capacitor . Simplicity/ elimination of potential issues occuring roadside . Besides the battery must be strong just to effectively fire the Boyer . Cap cost me $ 2.25 and the electronics guy told me they all dry out sooner or later. Talk of drying out want's me to crack open a beer..
 
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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