ideas on what happened?

[raindriver]

Put the '64 CA78 back together after replacing carb, some seals and ignition parts. After a couple of false starts, I got the carb floats and ignition properly set up (thanks again to the great folks on this site), and it was running nicely on a test-drive when...

Engine died while cruising at 30 mph in town. Before I could even pull over, a nice waft of white-ish smoke and a distinct smell of burning wires had me killing the key and whipping off the side cover to disconnect the battery.

Got her home (surprised to realize I can fold down the handlebars and fit her into the back of my compact SUV), the main fuse is blown, but I cannot see any visible melted wires or other evidence of shorts, fires or such problems.

I guess I'll just keep stripping off parts until I find the problem - but I wondered if anybody might have any ideas on what happened?

[305nutt]

might look at all the wiring where it bends in or around the frame for raw spots where the wiring could have grounded out on the frame.

[conbs]

Take a look at your rectifier. You may also want to check the windings in your dynamo. Search this site for the correct ohm readings accross the different wires, but if you could smell it getting hot and its those windings, they will probably read a short to ground.

[OldHarley]

Take a look at your rectifier....

Years ago television sets had selenium rectifiers, like our bikes. When they went bad their smell was that of rotten eggs.

[raindriver]

Thanks for tips, folks.

When it went there was no rotten-egg smell, more of a burning-plastic smell. So I think I have a short in the harness... well, it's Saturday, so I can have a good look. Will let you know if I figure it out.

[raindriver]

Well...two days later and still looking.

I've found one rear light line that looked slightly molten at one point, and showed cracks at another. It's a skanky bit of wire that looks to have been added by a P.O., not integrated in harness. I have winkers from a CA72 on my CA78, which might explain the bodge.

I've also found the green that runs from coil to condenser is grounding (a simple line continuity test on the multimeter shows flow whether I check the two ends of the wire, or just one end and ground...that's not right, is it?).

So I guess I have to drag the whole doggone harness out and pick it apart to see what damage has been done. I'll report back when I've got it figured...which will hopefully happen before the full year's insurance (that I bought the day before it died) runs out. It really rankles my wee Scots heart to be payin' the price and not gettin' to ride!

[conbs]

Check your fuse.