R50 - headlamp bucket electrical fire - wire 31

[Luddite]

Whilst riding the other day I noticed the regulator light coming on at medium rpm, accompanied by smoke coming out from the h/l bucket. Taking the lens out, I found wire 31 (h/l bulb earth?) insulation completely melted away. No other damage, no obvious points of contact. I disconnected everything and rode home on magneto only. Checking the bike over today, I can find nothing wrong electrically. So I'm very reticent to continue using the bike (my usual daily transport) without having buttoned down what caused this.

Any ideas? Anyone had this issue?

Cheers!

[schrader7032]

The ground connections at terminal 31 go to: headlight/parking light; generator; and brake/tail/license plates. I would follow the ground wires to each location and then inspect each item carefully to see if there are any chaffed or rubbed wires. It would seem that somewhere something has failed.

[Slash2]

does your horn still function?

[butch housman]

When u get it figured out put a 30 amp fuse in the circuit at the battery...or maybe a 25 amp

[bpw]

Might think about a complete re-wire, I did mine a couple months ago. Only takes about a day of work, you can add fuses and relays to modernize the system and it really improves your confidence in the bike. I didn't care about originality, so I made a bunch of changes but everything is hidden under the tank so it looks pretty original except for the keyed ignition switch I added below the battery tray.

By the time you cut open all the insulation to check the existing wires and clean the connections, it really isn't much more work to replace them. I had been putting it off for a few years, and it wound up being way easier than I expected.

[Luddite]

Thanks all for the replies.

The harness is a relatively new one from Uli's. It's good quality and I have confidence in it per se.

I've been meaning to put a fuse on the bike for about a year (the fuse is on my workbench, even). I guess this is my punishment for procrastination. I'll learn this lesson, eventually.

Neither horn nor indicators are working which is my current focus of attention.

Still a work-in-progress, I'm a bit time-poor at the moment. Thanks for all of the answers/help so far.

[Slash2]

Thanks all for the replies.

The harness is a relatively new one from Uli's. It's good quality and I have confidence in it per se.

I've been meaning to put a fuse on the bike for about a year (the fuse is on my workbench, even). I guess this is my punishment for procrastination. I'll learn this lesson, eventually.

Neither horn nor indicators are working which is my current focus of attention.

Still a work-in-progress, I'm a bit time-poor at the moment. Thanks for all of the answers/help so far.

Had you recently removed the horn and reinstalled before this happened for any reason?

[Luddite]

Nope. Completely untouched other than the usual servicing for the past year, except the front wheel's been out countless times in my epic pursuit of squeakless braking.

No hint at an electrical problem until the Incident. Standard filament main bulb, LED pilot, speedo and taillamp.

[bstratton]

indicators and horn are on the same control assembly. sounds like you are narrowing things down.
Do you have a schematic.