450 RT Magneto

[cgrace]

I am attempting to sort out the electrics on a 450 RT I am restoring. The magneto/alternator has three wires. The rest of the system is simple, a coil and points and condensor. I assume one of the wires is to the coil...the others for lighting and brake light. How to determine which wirw goes to thew coil? What should the points be set at? Any other advice on settting up the ignition?

Chris

[DewCatTea-Bob]

____ Welcome as our newest listed-member Chris !


" The magneto/alternator has three wires. "

____ What colors do your three (wide-case) alt.wire-leads have ?
__ Do you have an ohm-meter?


" What should the points be set at? "

____ Their gap should be set between 14 & 18 thousandths.


Tillater,
-Bob

[cgrace]

I do have a volt/ohm meter. There is a white and a red wire and believe the third is white as well...though a bit discolored.

Chris

[cgrace]

I stand corrected. A red, a yellow and a white wire. White reads infinite ohms to ground...the other 0.

Chris

[DewCatTea-Bob]

" A red, a yellow and a white wire. White reads infinite ohms to ground...the other 0. "

____ It seems that you must have a stock 450R/T 4pole-alternator then, (as most other 450s with 3 alt.wire-leads, have 1-Red & 2-Yellow).
Also, YOUR*R/T's White wire-lead ought indeed read "infinite" -('open') to Ground, (* only for the 3-wire alt.version),, but, WHICH other one is "0" ?
No matter, just confirm that the White & Yellow wires read 'closed' -(which is nearly 0.0-ohms) between each other, (but not to Ground). - Neither the White nor the Yellow alt.wire-leads should be indicated as closed-circuit -(near zer0) to Ground ! _ Whilst the Red wire-lead should be the one that measures as "0" / closed-circuit to Ground !
____ Do you wish to wire-up your R/T just as stock ? _ If so, does your R/T include the optional lighting-kit ?
__ Most 450R/T owners (these days) wish to convert their R/T for legal-operation of street-riding... Is that your intent as well, or do you just want to get it running (for off-road) ?


DUKE-Cheers,
-Bob

[cgrace]

Thanks for the help. I'll have to check the other leads and confirm the readings.

I had an RT in the 70's and did hook up a lighting kit , but this bike was a barn find and had no lighting. If I could find some suitable gear I would like to make it street legal, but for the moment I want to get it back running after a long rebuild and a lot of interruptions.

CG

[DewCatTea-Bob]

" but for the moment I want to get it back running after a long rebuild and a lot of interruptions. "

____ Alright then Chris.
__ Many people with a Duke that employs the same alternator-model/type -(often incorrectly referred to as a "magneto"), which has become known as the "40 watt" alternator-type (somewhat due to it's particular circuit-ways of it's two separate power-coil windings), quite often (mistakenly!) wire-up the Red-wire to the ignition-coil because it's the only wire (of the 3) which will produce any spark. _ However THAT alt.wire-lead was actually intended for the lighting. ...
For R/Ts without the lighting-kit installed, the White-wire ought be grounded to the ign.coil-mount, while the Yellow-wire is connected to the same ign.coil terminal-post as is the wire-lead which goes to the points.
The opposite terminal-post of the ign.coil is also to be grounded, so you may choose to connect that terminal directly with the White alt.wire-lead if you prefer that most direct connection.
__ Then you can go-ahead & try checking for ign.spark, and then let us know how things went for you.
____ BTW, since it now seems your R/T uses the same alternator-type as has already been touched-on elsewhere (within a number of other threads here), you ought be interested in reading-through one which I recall being very quite similar to YOUR inquiry ! ...
It's titled: "Wiring my Duc (from welcome thread)", and that particular thread is (currently!) found located near the middle of page-6 (of these thread topic-pages). - (Quick-link... click: viewtopic.php?f=3&t=228#p1425 )
I think you'll find it worth a look, and when the time comes that you're more interested in a better suited electrical-system for street-legal lighting, then there are also other threads (already established) covering that particular subject as well ! _ So be sure to ask, whenever you're ready to take-in more of such info.


Hopeful-Cheers,
-Bob

[cgrace]

I have taken the oportunity to check the various leads with thew ohm meter and it appears I may have a problem with the yellow lead. It reads open between the white and yellow...closed to ground.

[DewCatTea-Bob]

" it appears I may have a problem with the yellow lead. It reads open between the white and yellow...closed to ground. "

____ Please confirm that I understand what you mean correctly...
Your ohm-meter reads near zer0 when you connect it's leads to ground & the Yellow-wire, and besides that, your ohm-meter also indicates 'infinite' between the Yellow & White wires ,, correct?
__ I WAS (fairly) sure of which alt.model you have due to your previous/original statement that the White wire-lead was indicated to be "infinite" -('open') to ground. - (Which had made sense!)
Since at this point all things are not consistent with that which I've expected, please do another meter-check reading-job, this time complete, between each of the 3 alt.wire-leads & ground, plus, meter-readings between each paired-up pair, of all the 3 wire-leads themselves. _ That's six separate meter-readings in all.
__ So as to make it orderly, you can copy the following & fill-out with your results (in your next post here).
1_Red to Ground = closed or open
2_White to Ground = closed or open
3_Yellow to Ground = closed or open
4_Red to White = closed or open
5_White to Yellow = closed or open
6_Yellow to Red = closed or open
____ Working with the (assumed correct) limited info currently available so far, I'm afraid that your alt.wire-leads may need replaced (if they haven't already been, in a non-stock arrangement). _ As having any SINGLE -(just 1) alt.wire-lead read as 'open' to Ground (as your White one is confirmed), must therefore lead to the conclusion that it's circuit is 'incomplete'.


Hopeful-Cheers,
-Bob

[cgrace]

"____ Please confirm that I understand what you mean correctly...
Your ohm-meter reads near zer0 when you connect it's leads to ground & the Yellow-wire, and besides that, your ohm-meter also indicates 'infinite' between the Yellow & White wires ,, correct?

Coreect...butI will carefully recheck tomorrow.

Thanks