I just bought a 1976 R90/6 basket case. It had been disassembled over fifteen years ago, for a motor rebuild and other refurbishment. The guy lost interest halfway through the process and stashed it in the corner of his woodworking shop. When I came over to see it, it was basically a dozen boxes full of loose parts, all nicely covered in a thick layer of sawdust. After a few hours of work, it's now a rolling basket case: Now, to the point of my post: I need some help assembling the headlight innards. Here's what I have: I also have a contact plate: I also have a flasher relay and a headlight relay. Three questions: 1: Can anyone tell me exactly where the contact plate and the relays are supposed to be fastened inside the headlight shell? The Clymer manual was no help on this. If someone has a photo of the inside of a R90 headlight bucket, showing where the various bits are fastened, that would be great. 2. Can anyone direct me to some info telling me how to connect all the wires? The main harness has 17 wires, and the handlebar switches have 7 and 9 wires. No idea how to connect them where they belong. 3. What are the parts marked 8 and 11 in this diagram?: I got the diagram from the parts fiche at maxbmwmotorcycles.com, and it didn't identify those parts. I Any help will be greatly appreciated!
1: Can anyone tell me exactly where the contact plate and the relays are supposed to be fastened inside the headlight shell? The Clymer manual was no help on this. If someone has a photo of the inside of a R90 headlight bucket, showing where the various bits are fastened, that would be great. The board is mounted at the back of the bucket with two short chrome philips head screws 2. Can anyone direct me to some info telling me how to connect all the wires? The main harness has 17 wires, and the handlebar switches have 7 and 9 wires. No idea how to connect them where they belong. Follow the color coding on your wires into the board. Some plug into the headlight relay and turn signal relay which you can figure out from the repair manual 3. What are the parts marked 8 and 11 in this diagram?: Mounts at about 9 o'clock as you're looking into the bucket to that silver bracket and the headlight relay is opposite it.
the screw and washer (3 & 4 in the diagram) go though the rear of the headlight shell and secure the circuit board in place - there are actually two screws and washers. The aluminium bracket on the inside left of you photograph is the mounting point for the indicator relay. The main wiring loop comes in at the bottom of the headlight and is secured by the metal loops, inside the shell, at the 7 and 12 O' clock positions. The black plastic sheathing should be in place here. Your loom looks like it's routed incorrectly and doesn't have enough slack to loop round inside the headlight. Your going to have to pull that back and route it correctly though the frames headstock so that it comes in under the headlight and on the top side of the bottom yoke. Once you get the routing in correctly the loom will loop round the headlight and drop down ready for connection to the circuit board. As a rough guide the wires with the 90° connectors push onto the circuit board on a coloured connector that corresponds to the wiring colour. The headlight bulb has it's own connector that plugs onto the circuit board.
I got the 1976 R90/6 diagram from this site: http://hstrial-wniglobalinc.intuitwebsites.com/BMW-LEDs.html Links are far at the bottom, great size for printing on big scale. Rember 1974 /6 diagram is different.
Stolen from Blaine's thread...you might get over there as it's full of good info. http://www.advrider.com/forums/showthread.php?t=537364 One of these is invaluable for rewiring a twin shock airhead headlight...called a MacGills forcep, used in anaesthetics. Can be bought over the net easy enough, and cheap enough. They reach right to the back of the shell with ease.
I don't know the difference between early and late 90/6's but here are some lovely wiring diagrams that airbear made up for the 1974 model. might be of some use. http://www.p-thomas.com/shared/BMW/74 R90 Wiring.pdf http://www.p-thomas.com/shared/BMW/74 R90 Pod.pdf
Steve, Here's a shot of inside my '75 R90/6. Happy to send larger files and shots from different angles (via PM?) if you think they'll help. Dave
If you need a headlight or turn signal harness check out http://wirewerkes.com/. He is a big contributor here on Old Cool.
Thanks, guys! Great info, just what I needed. I'm going to try to finish up the wiring now that I have those example photos to work off of.
Hi, New to the forum and to the MC world. was charmed by the old look and feel of the BMW airheads... had to get me one. and here I am, trying to get it going. =) Many thanks to the info above, it really helped when i restored my -74 R90/6 (original headlight and turn-signals had been removed by previous owner to fit a large Pichler faring). Got the electric stuff going but experience problems with the headlight. No parking light, half-beam works as does the high-beam 'blink' (don't know what's called) but not high-beam. Looking in the photos above and reading online there is talk regarding the headlight relay (this i do not have installed today as it did not come with the spare parts), is this something that could be the root cause to my high-beam problem or is the relay just a way to lower the power in the system? if the headlight relay is essential to install I would be very happy to get some info on what kind of relay i'm looking for and perhaps where to get it for a reasonable price. Can see that this tread has been inactive for quite some time, but hoping that someone might help me as well. Hope to hear from you guys BR, Frans
Fraje, I see you are a noob around here... welcome! You ask good questions, what I suggest is that you start your own thread with the questions, but do it on the Airheads sub-forum... that is where airhead wisdom (whatever THAT is) hangs out
