Replacing wiring harness?

[Redbaron]

I have had electrical headaches with this 1980 R65.  Found a coil mount had rusted and cracked and prior owner ziptied it to the frame.  I found the red power wire to ignition was cracked and broke inside the original wiring harness.  After running new red wire from battery direct to ignition, the bike will crank and almost run but volts drop off immediately, like a short somewhere.  The start relay, coils, starter, etc all check good.  Start button and kill switch are good.  I am about to buy a new wiring harness and see OEM harnesses are about $500, WOW!  Please let me know if you have ever replaced the harness or if there is something else I need to check.  Thanks again for the earlier comments, big help.

[georgesgiralt]

Hi !
Did that on my 82. I was fortunate to buy from a closing garage which got the harness a few days before closing and, thus, I paid half price for it.
It is an involved job to do because you have to think twice for the routing of the thing in order not to pinch it when putting all the stuff on the frame and not having it crease too much when you turn the handlebar.
But once done properly, it is a game changer.
Look for pattern wiring makers in your part of the world and discuss with guys like motorworks or motobins in the UK. You may get lucky.
Last resort is to make one yourself. It is also very involved because IMHO you have to follow the BMW color code for the next time you will be looking at it and it involve removing the old harness, make a new one using the old as a pattern, and properly put back the new harness on the bike.
Cost is not that better when you have factored in the price of the copper wires with the correct colors...

[Bob_Roller]

Don't know if this will help you out cost wise for wiring harnesses or not . Was it the forward coil mount with the issues ?
It's been mentioned over the years that it can b e a problem .

https://www.euromotoelectrics.com/category-s/2182.htm

[Redbaron]

Hey Bob Roller thanks for the info for euromoto. I found the larger 2 wiring harness pieces OEM from MAXBMW. The largest piece is $175 from MAXBMW and Euromoto is asking $299 for their aftermarket harness.  It is the front coil mounting bracket. The bracket broke off from the welding and the coil was held by a zip tie.  The grounding point and wires were very loose but some how worked to achieve a ground for the coils.  I cut the remains of the mounting bracket off the frame and drilled a hole in the frame to mount the coil and secure the ground wires.