Triumphrat

RetroRod

Hi Webby,

A man of all seasons that you are, I was going to PM you on this (did not want the world to know that I am ignorant in certain 12vDC electrical matters). However, in the interest of our brother Triumph owners who may wish to know this also, I have put personall interests aside. (I know, very magmanimous of me).

In a response to another poster on this site, I recalled the old 2MC capacitor ignition used on these old Triumph turds during the fifties & sixties. Very helpful system as I recall, and used frequently enough (I can remember using it comprehensively on my old '57 Thunder Bird I think it was) when I was too broke to replace a dead battery.

I had put this question up some time ago on the BB forum and someone was kind enough to send me a copy of a wiring diagram for the 2MC, but I've misplaced it and so remain ignorant in this regard.

Riding home today from a place a fair way removed from home, it occurred to me how inconveneint it would be for the battery to die without much notice (I always ride with the lights on these days. (The Y generation cannot see, and if they look, they usually have a bloody mobile phone stuck to their ear or are texting a message that just cannot wait).

So says I, what about that old 2MC ignition? That's what's called for here. I have a 4 way ignition switch, which I assume if set in the reverse position would provide an independant circuit for a 2MC setup. The w/shop manual I have for this '72 (section H18) mentions the 2MC setup, but the maual has no wiring diagrams at all.

Not an electrical theorist by any means, I cannot imagine the circuit I need, other than to say I guess the feed would have to be from the 12vDC at the rectifier, then directly to the 2MC? then to the normal 12v feed on the iggy, then to the 12vDC on the Pazon, via the reverse switch position?. Not terribly complex I would think, but nonetheless I am not very certain. Just not certain what happens when the thing starts up and all that AC gets converted into DC, shoved into that paper capacitor, well you know what I mean. ****, poor old Retro could be blown sky high!!

The real problem will be whether poor old Retro can find the oomph required to get that alternator pumping AC to the rectifier on the kickover (oh to be 20 again!!)

Now, can you help a poor old guy from down under?? RR

RetroRod

Well I guess I called this right Webby, here you are locked down somewhere at -20c, but on the other hand you could be swanning it in sunny Dubai at 27c. either way you don't seem to be at home.

Wherever you are, get the books out and find that wiring diagram!! RR

Webby

Hi RR,
It sounds possible, I'll get my tiny brain into gear and have a think about it, I'll also have a look at the books and back to you in a few hours.

Webby

PS: It's warmed up today, 13°C and pissing it down!

Webby

Hi RR,
Sorry, I had no time yesterday to have a look and I'm running out the door in an hour to catch a flight to go and see my Dad in the UK (If the flight from Paris is not cancelled!)
I'm back home on the 27th, so I'll have a look then, have a good Christmas, and may all your oil stained dreams come true for 2010.

Have a good one

Webby

henryanthony

Hi RR,

There is a schematic available at this link:

http://books.google.com/books?id=6QA...acitor&f=false

Henry

Snakeoil

First, Henry, that Google books links looks like a great source of info. Appreciate you turning us on to that.

RR, the battery eliminator is something I've seen around for as long as I've been riding. I'm sure you can still buy them from bike accessory suppliers, complete with instructions on how to hook it up. Accel makes one for Harleys with generator or magneto systems. I did a quick search and found this on ebay. Looks like what you are looking for. http://cgi.ebay.com/ebaymotors/Trium...item588519342b
regards,
Rob

RetroRod

Thanks Rob, that's the little bugger alright. They are readily available all right, my issue was just how to wire them in. It seems that you can have either, or and or. Battery and cap together, batt and cap on separate circuits, or just cap.

I recall form my youth (now there's a miracle in itself) that one turned the key in the opposite direction to use the 2MC ignition, suggesting the the cap was not in use on "usual ignition", and was only energised when required. I have read since that the batt and cap can be wired in together, so that the cap kinda acts as another mini batt in parrallel. Not sure I want this as the the cap will get done wore out from everyday use (though I understand it takes some heat off the Zener diode by absorbing excess voltage as well)

The plan is to have the cap on an independant circuit, engaged by the reverse position on the iggy switch. Anyway that is plan, we'll see what transpires. In any case I'll advise here the results for public consumption.

Good to see you have a heated den and that puter has not done gone and froze over. RR

Snakeoil

I was not aware of this mod from Triumph. I just took a look in my manual and sure enough, there is it in section H18. No wiring diagram, but a simple description on how to connect in the capacitor.

What puzzles me is the paragraph on shelf life for the capacitor. I suspect they are talking about its ability to hold a charge, but they might very well mean the life of the capacitor itself. It says the shelf life is 18 months at 20 C and 9-12 months at 40C. That just does not seem right to me. It has to mean its ability to hold a charge. I think the comment is made because a bike that has sat for a long period might not start unless the capacitor is recharged.

Anyone know for sure if this shelf life time is for holding a charge or the actual life of the capacitor.

Also not familiar with a switch with a reverse position. The manual section makes no mention of this. Was this something only offered on certain models or markets?
regards,
Rob

RetroRod

I had planned to buy two at a time. The spare I will vacuum seal and keep in the fridge. The switch on the '72 has a reverse position. I have yet to test this with the voltmeter to see just what circuit is made when in that position.

I cannot say about shelf life, other than to say that the one on my old '57 Thunderbird must have been years old, but worked OK. RR

RetroRod

Thanks Henry,

Amazing just waht is out there on the WWW. RR