Trying to revive a 1973 Roadster

Picture two is correct.

GUTS said:

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I think the 2MC connections could be wrong? I think the photo shows one brown/blue(-) and the red(+) are connected to the 2MC 'common' terminal and the second brown/blue is on the single positive terminal?

You sure could be right, I took the wires off to clean it. I do apparently have voltage to the switch finally but I can't get any thing to energize. I ordered a new ignition switch today. I am still very gratefull for the help you guys are giving me.

GUTS said:

You sure could be right, I took the wires off to clean it.

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I suggest you check it before you go any further. If it is connected wrong, then it may have damaged the 2MC, so I recommend you disconnect the wires from the 2MC and fit a jumper wire between the two brown/blue connections before you continue testing (check volts between the ignition switch brown/blue (not brown/green as you said previously) and ground and/or battery(+).

I put a jumper in the 2MC like you said and now I have headlight, tail light and brake lights. Seems as though I need a new 2MC. I checked for spark and I still don't have any but finally, some progress.

GUTS said:

I put a jumper in the 2MC like you said and now I have headlight, tail light and brake lights. Seems as though I need a new 2MC. I checked for spark and I still don't have any but finally, some progress.

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Good.
So, I take it the connections were wrong, as that probably accounts for the odd readings?
The factory manual has information on how to test the 2MC, but you can do without it (if you keep the battery charged).

Les,
Good eye on the capacitor. Do you have a picture of one from the bottom. The one I removed from my bike only had two terminals and they were screws with ring terminals. All the browns went to one side and ground went to the other.
I also don't understand why why the second picture with VOM black lead going to negative battery and red lead going to Br/Blue is considered an odd reading. VOM is seeing 13 volts going through a loop with correct polarity.

Thanks,
Pete

Deets55 said:

Good eye on the capacitor. Do you have a picture of one from the bottom. The one I removed from my bike only had two terminals and they were screws with ring terminals. All the browns went to one side and ground went to the other.

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http://www.motorcycle-memories.com/stor ... 05401.html

Deets55 said:

I also don't understand why why the second picture with VOM black lead going to negative battery and red lead going to Br/Blue is considered an odd reading. VOM is seeing 13 volts going through a loop with correct polarity.

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IF it had been wired correctly, then the probes would have been at opposite ends of what was basically be the same piece of wire = the brown/blue, thus there would be no circuit so no voltage reading. However, with the wires connected as they appear to have been, continuity between the battery and the Ign. switch had been "broken" at the 2MC as the two brown/blues were not on the common terminal, the 'hot' brown/blue wire from battery(-) had effectively been isolated, as it was connected to the single 2MC 'ground' tab.
The (I think) switch half of the brown/blue being 'grounded' (as the red was connected to the other common terminal) that section of the brown/blue was now POSITIVE which resulted in a circuit when the probes were placed between battery(-) and the Ign.Sw brown/blue connector.

Les,
After seeing the bottom I follow your train of thought. I was thinking like you but the other direction. The br/bl on the correct terminal was completing a circuit, and the br/bl with the red was the broken circuit.
I guess what ever the case GUTS needs to get all the browns together, and reds together, and as you suggest ditch the capacitor.
That big 5 gang connector in the prior pictures, is that common on the earlier bikes? The only place I have seen them is on the taillight and inside the headlight shell as a common ground. Everything else are either single Lucas or molex on my MKIII.

Pete

Deets55 said:

After seeing the bottom I follow your train of thought. I was thinking like you but the other direction. The br/bl on the correct terminal was completing a circuit, and the br/bl with the red was the broken circuit.

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I'm not 100% sure I've got it right, but if the brown/blue from battery(-) had been the one paired up with the red ground wire at the 2MC common terminal then I'm fairly sure that would have resulted in a dead short!

Guarantee that was a big part of GUTS's problem. Good eye!
Pete

GUTS said:

You sure could be right, I took the wires off to clean it. I do apparently have voltage to the switch finally but I can't get any thing to energize. I ordered a new ignition switch today. I am still very gratefull for the help you guys are giving me.

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LOL, "self inflicted wounds"... we've all done it.

Amazing Les has solved the puzzle again! From thousands of miles away, no less. Good job! :mrgreen:

Thanks Les, now where is the spark to my points? :wink: Stupid question time. I still can't get spark at the points and this positive ground stuff is still weird to me so when I put the battery directly to the coil to see if the points spark, does the connection from the negative terminal on the coil go to the negative or the positive on the battery(I think had it on the positive when I checked for spark last time).

GUTS said:

I still can't get spark at the points and this positive ground stuff is still weird to me so when I put the battery directly to the coil to see if the points spark, does the connection from the negative terminal on the coil go to the negative or the positive on the battery(I think had it on the positive when I checked for spark last time).

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Connect battery negative to coil negative, as shown on the wiring diagram. Remember that although the electrical system is 12v the coils are 6V so don't prolong the direct battery test longer than is necessary unless you include the ballast resistor.

Also, the wire from the ballast resistor to both coil negatives is normally white/purple (in original harnesses), although it isn't marked on the wiring diagram.

Still no spark from either coil. At least the lights are nice to look at, I can sit on it with the lights on and go "vroom vroom".

Better close the doors , so the neighbours don't see you . :mrgreen:

Just put on the headphones , or p. a. & connect here . http://www.youtube.com/watch?v=0AuvkW4CmaQ :mrgreen:

Coils ! COILS ? call THOSE Coils ? ? :shock: Er , used lucas CAR coils have a 505 of better , or is that worse , failure rate . New used . :?
A few WIRES on , and tap one to the other bit , with a HT lead , and there should be what passes as a SPARK . a 1/2 in Blue & White SPARK
will get a Engine Going without a misfire - stumbling - lethargy or flatulence . only second hand lucas Sports Coils are capeable of THIS .
All but one STANDARD do a weak red / yellow 3/8 in ( 9 mm in your lucky , more like 8 . or 6 , or a tiny litter , . . . ER . )

those clamps can crush em , the oil can leak out of the can . etc . :shock:

CYCLE mags great coil test , from there Daytona Ducati SS build , rated the Lucas Coils as pathetic , or worst . PARTICULARY the 6 v .
Voltage marked on end / base .

But put a live wire on and tap the other wire to earth . it should indicate if theyre WW1 surplous . ( likely better quality if they were )

Check over the back fence for Morri 1100s , for spares .



if theres no spark , I here theres plenty of Kawasaki ones locally .

Okay, as per suggestions by all you fellas I have so far:

Bypassed fuse holder

Took apart and re-connected all the wires in the black rubber blob

Tightened and cleaned a dozen other connections

Bypassed the 2MC(after I fried it )

Tested the zener diode

Checked primary side of coils(1.9 ohms on one and 2.1 ohms on the other)

Wired battery directly to coils one at a time to check for spark(still none)

Continuity tested all the wires I could find(all good now after the wiring repairs)

Continuity tested from frame/engine to battery +(good)

Checked voltage from hot switch to frame/engine(13+ volts everywhere)

A continuity test on the black/white wire and the black/yellow wire shows good from the coil connection to the points.

After all this I do have lights and brake lights with the key in the proper position but still no spark at the points. Which coils do you guys recommend cause it seems I need to buy a couple. The only things I can think of that I haven't tested are the rectifier, ballast resistor, and the capacitor pack up by the ballast resistor. I have a new 2MC and a new ignition switch coming but I don't think the problem will be cured.


I may have left something out but that's what I've tried so far and I surely couldn't have got this far without the help I am getting.

With that reading on the coils, I still wouldn't be too suspicious of them yet. Condensers, can you test them with your VOM? Some have a C position. At worst you can see if they are shorted. Are you sure the points and timing is near correct? Do you see any sparks at the points when they open and close? Test the resistance between the coil primary and the case (ground) too. It should be very high. I'd still like to know the voltage reading on your coil minus to earth when you try starting it. Can you test the current to the coils when trying to start it?