Capacitor, keep or remove?

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I am in the process of adding a Podtronics box, and a CNW coil and a Pazon Surefire EI as well as a CNW starter with Lithium battery. As the CNW coil and EI means I can remove the condensers, ballast resistor and the 2 x6v coils, and thus tidying things up nicely, when I fit the Podtronics I’ll remove the zener diode - can I remove the capacitor to make a bit more room? Or is it necessary to retain it?
 
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I wish I had a recommendation for you on the capacitor mate. My '72 did not have on when I got it, so I can say that the bike starts and runs fine without it, as long as your battery is good and charged.
 
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The capacitor allows a STOCK bike to start with an essentially dead battery. The mods you are making will preclude the capacitor from being able to do that. So there is no reason to keep it.
 
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The capacitor allows a STOCK bike to start with an essentially dead battery. The mods you are making will preclude the capacitor from being able to do that. So there is no reason to keep it.
Plus caps , they have a shelf life / usage life that likely expired long ago. Eliminate it and run things off of your new fancy battery.
 

gortnipper

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The capacitor allows a STOCK bike to start with an essentially dead battery. The mods you are making will preclude the capacitor from being able to do that. So there is no reason to keep it.
So, I ran my 74 for 20 years with a RITA, zener and a blue can with the same dead battery. I knew it was dead and didn't care.

Which mods, specifically, preclude the capacitor from being able to do that and why?
 
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I’ve just read the fitting instructions for the unit, and it says it has in inbuilt capacitor - perhaps I should read instructions first? :eek:
 
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The capacitor allows a STOCK bike to start with an essentially dead battery. The mods you are making will preclude the capacitor from being able to do that. So there is no reason to keep it.
A capacitor alone WILL start Surefire, Trispark, Boyer analog...
This has been discussed many times before.
You don't need to have it permanently connected, but in case of a flat battery, it will make the difference between riding and pushing.

Don't leave home without it .

 
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The cap sends a charge into the windings of the stator to excite the coils and produce current, just as a good battery does. If your setup has an inline capacitor, the blue can is just excess weight.
 

batrider

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If the capacitor is still good I think there is a benefit in keeping it to provide more filtering for the 12vdc power.
 
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"Which mods, specifically, preclude the capacitor from being able to do that and why?"

My first thought was the electric starter! But, of course you could still kick or, in my case, bump start the bike (I removed the kickstart lever a couple of years after installing the Alton E start). However, re the Cap - my own experience was that the cap could not start the bike with an EI/Podtronics. So I removed the cap when I installed a new wiring harness years ago. Whether it was the Boyer or the PodT (or both) that precluded the cap from starting the bike, I don't know. But I could not kick start the bike on just the cap.

Further, I can see no point in the cap, even if it will start the bike. There is a battery and a charging system. Certainly, in the days of motos with marginal DC generators and tiny batteries, there was a logical reason for the cap. Batteries were often flat. Nowadays, it would require some pretty dedicated lack of attention/maintenance of the battery/charging system to make the cap necessary.

OTOH, there is certainly no need to remove the Cap except, as the OP observed, it takes up some space. As far as whether it will actually (kick) start the OPs bike in the configuration it is in, it's easy enough to test. Disconnect the battery and try to start it! ;)
 

jaydee75

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I ran my pure stock (then) Mk3 on the Cap without any battery at all for several years. I figured a dead battery would just soak up the volltage from the cap when I kick. Now I wonder if you have a dead battery should you disconnect it for better Cap performance in an emergency?
Jaydee
 
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I ran my pure stock (then) Mk3 on the Cap without any battery at all for several years. I figured a dead battery would just soak up the volltage from the cap when I kick. Now I wonder if you have a dead battery should you disconnect it for better Cap performance in an emergency?
Jaydee
Yes, you have to disconnect the dead battery.
And make sure all other power consumers are switched off.
 

Tornado

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I had a battery bloat up after a spirited ride. The Zener had failed and volts went over 15v. Discovered the issue once stopped for fuel. Got it started after some fiddling about. Would stumble if I switched on headlamp. Even just turn signals would could near stall at idle. So pretty sure it was only working on the capacitor. Got me home. I'd tested the cap previous season and still worked as spec'd in workshop manual. Bike is EI (vape wassell boyer-esk). Had orig rec and zener at the time. Cap is A keeper for me.
 
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I recently remade the electrical system on my BSA B40 unit single. It had a Boyer Mk IV, now fitted with rec/reg and MC2 replacement from Paul Goff. The modern capacitor is much smaller than a MC2 and don't need the spring used for the MC2. Can be fitted anywhere with a tyrap. The rec/reg takes less space than the Zener with heatsink. Bike is as easy to kickstart with or without battery. Has an ignition key with 3 positions. Off, normal, emergency (battery disconnected).
 
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SO, again, to the OP, try to kick start the bike on the Cap. I couldn't get mine to start on the cap but based on posts from others, obviously it will - at least in some non-stock configurations.
 

maylar

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Plus caps , they have a shelf life / usage life that likely expired long ago.
An old analog VOM with ohms function will tell you if the cap has become "leaky" (resistive), in which case it'll drain your battery when not running. I have a new one that I got off Amazon, but haven't fitted it yet.
 

illf8ed

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So, I ran my 74 for 20 years with a RITA, zener and a blue can with the same dead battery. I knew it was dead and didn't care.

Which mods, specifically, preclude the capacitor from being able to do that and why?
Thanks
I just put my rebuilt RITA back in my ‘72 and still have the blue can, zener and original rectifier.
 
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