Fried white and red ignition wire on my 72 twin cam

[GPS]

So I am a new owner of a 72 twin cam europa. I am having problems with the white and red ignition wire from the solenoid
It as fried next to the ignition switch and is not allowing the car to start. What would cause the wire to get that hot?
I ran a bypass wire from the same connection on the ignition switch out the passenger window to the solenoid and got it to start this way.
However I could feel the heat building on this wire next to the ignition switch. Not sure where to turn next.
Thanks in advance for any help to figure this one out.

[BDA]

  GSommer98!!

Congratulations on your new baby!

First I would suggest you change your handle from your email address to something else. Unfortunately, there are people in this world (I doubt any are members of this group but more likely they might scrape email addresses using a bot) who collect email addresses so they can spam you with a lot of crap you won’t want. Most of us spell out email addresses for this reason. It’s probably a low probability but better to be safe than sorry. If you do that, you’ll probably want to delete your post and post it again.

As to your problem, if your bypass wire did not get hot, there iis probably a short in that wire. If your bypass wire got hot too, then your solenoid is probably going out and has increased resistance.

[GPS]

Thanks for the scurity advise as I was not paying attention to these deatils as I noemally would.
I will procede to check the solenoid.

Cheers

[BDA]

Let us know how it goes!

[jbcollier]

The current flow through the RW wire can be quite high.  Spiking 30+ amps before settling down.  If the spade connection gets a bit iffy die to corrosion or being loose, then that amount of current can produce quite a bit of heat.  That's why the wire is melted by the connector and fine elsewhere.  If there is a true short, and current is going even higher, the whole wire would get hot and melt.

I would change the switch and fit new connectors on the RW wire and brown feed wire.  Use w-crimp connectors.  Then add a relay near the starter to take the high amp load off the ignition switch.

[GPS]

Wow thank you so much for the info! That really helps to point me in the right direction. I am going to go out on a limb and show my electrically challenged self. What type of a relay would that be to install? Are their brands or a certain type/ size I should be looking for? I am guessing mounting it to the side of the engine bay. Is this small enough where I can just zip type to the existing wiring harness? Just want to get this right. You also recomend starting with a new igniition switch?
Thanks again!

[jbcollier]

You can just change the electrical part of the switch.

Below is a schematic of a typical starter relay:



RW wire goes to 85.