Monthly Archives: October 2011

More front end tear down…


Solving the eccentric pin issue allowed me to move forward with the removal of the fork sliders. I was surprised how much fork oil was in the forks, probably around 150ccs each, nice oily surprise. When I removed the fork sliders I realized how damaged they were from the accident, but the stanchions looked great. I will end up taking them off down the road, rolling them on a piece of glass and seeing how straight they are. The right fork slider was much more damaged than the left, but the left one had some damage as well, so I replaced them both. I had purchased a whole new front end for this bike, a used, but new to me front end and so I replaced the damaged fork sliders with the much better ones that I had bought separately.


Tearing the front end apart


When I took the fork filler caps off there was a a sizeable amount of force that blasted the cap off in my hand. I kept better pressure on the second one as I took it off so it wouldn’t break my hand in the process. The pvc spacers must have been in place for the Luftmeister fairing. When I reassembled, I left them out since I’m not putting a fairing back on. One thing that wasn’t super clear in my manuals and online was the fact that once the hexagonal bolt and spring are removed from under the break caliper, the eccentric pin pulls out rather than unscrews. The eccentric pin is an interesting design element to allow for adjustment of the brake pads to the rotor. I used one of the other bolts from the brake line bracket to slightly thread into the eccentric pin and pull it out. You can see that this sequence of photos stops at the distal end of the eccentric pin…I was stumped…

Photos before wheel removal and bottom fork removal/replacement


These preliminary photos were mainly to make sure that after I tore everything apart, I could get it back together again!

Figuring it out


So the summary of my latest discoveries is that this bike is an R100/7 that had a luftmeister fairing put on it. this is great news from a wiring perspective because I can just put on the side blinkers, order the wiring for them and a new light plug harness, put on about 10 replacement wires for wires that were fried during the wreck (from the heat of a broken light I believe) and the electrical should be much improved. I also order a new light relay as well, just in case. I need to create some new connections from the tail light and rear turn signals to the under seat harness connection and hopefully that part will be done and I can turn my attention to some carb clean up….shade tree mechanic in October….in Colorado…

Wire spaghetti


For the life of me I could not figure out what this big cable was that was in the mix of the other headlight wires. Down the road I found the other connector in a box of parts and realized it was the connection for the Luftmeister fairing. Once I figured that out I was able to take it and its associated wires out of the mix.

BMW MOA such a great resource, thanks fellow riders!


Here’s a volley of discussion that I’ve been having on the BMW Motorcycle Owners of America site:

Would like to convert a wrecked 1977 R100RS to R1007

I’m just wondering how I can go about converting this bike that I think was originally a 100/7 and then at some point was converted to an RS, wrecked and now I would like to take it back to a /7. Everything is cool with that, but I can’t figure out how the wiring should work on it to get it back to a 7. If you’d like to follow my progress, I have a blog going at

-Ya gotta good resto going and it looks like you have a pretty good handle on getting to a finished product. Take your time and get it right, it will give you a chance to learn your bike with total hands on experience. I saw your pic sitting on the bike, it appears you would have been to big to sit behind a fairing. I’m looking forward to see how you progress.

-Thanks! I love riding and have a Suzuki 1985 GS 700 that I’ve been maintaining for the past 14 years. The electrical in the headlight of the BMW is a real surprise, but I get it. I’m just not sure that I have what I need to take it to a R/7 rather than an R/RS…I think I need to find a good salvage yard and pull a full harness off of an R/7…thanks for the feedback –


-the photos you show are of a /7 as you call it, ie the ign switch is installed in the head light ears which are also installed ,as these should not be installed if the bike had an rs fairing installed ? perhaps you have the models confused?


-I agree with the previous poster, I think you’ve got your models confused. If the bike looked like the one in the Butler and Smith advertisement it wasn’t an RS, that is an aftermarket Luftmiester fairing they slapped on. The ignition switch should be on the left headlight “ear”, it doubles as an attachment point for the headlight bucket.Yes there is a lot of wiring in the headlight shell. Fortunately it is color-coded at the fuse panel and there are plenty of resources to refer to if you get lost. Granted it has been many years since I ditched my old Lufty, but they used the same color wiring as BMW which helped simplify the process.

Good luck!

“…your body is not a temple, it’s an amusement park. Enjoy the ride” A. Bourdain
-If you do think you need a harness, you may want to consider getting a new one as opposed to a used one. It may save you some future headaches. I put a new harness on my ’77 R100RS due to multiple “no spark” and/or “no start” failures. Once we looked into the root cause, we found multiple spliced wires, bad connectors, etc. Replaced the harness with a new one, and I’ve been trouble free, at least from an electrical standpoint, since. As I recall, they’re not that expensive.
Brad D. – Member #105766
’77 R100RS – Black Beauty (big pipe, baby!)
’77 R100S – Ruby (S in RS clothing)
-yup, looks to be a standard /7 with a Lufty mounted on it.
-ign switch on an RS was in the cockpit area above the gauges (between voltmeter and clock), not on the headlight (which would have been fully inaccessible).
-those flat side brackets (visible in picture dsc 6958) are correct for a Luftmeister or Windcrammer, but most certainly not an RS.
-no sign of the RS “spider web” fairing bracketry (should have bolted to the steering tube)
-those handlebars would never have worked on an RS fairing.all that just means that you should have less extraneous wiring segments to deal with. the only differences between an RS and a std /7 would probably have just been a sub-harness for the volt/clock, adapters for the turn signals (maybe), and shorter lines to the handlebar controls. good news, less to do for you!


Ride Safe, Ride Lots
-Whats the vehicle ID number? That will help determine what it started out as. That might also match what it is now. The 77 78 R100S shared wiring harness with the 100/7, 750 and 600. The straight /7 touring bike had separate wire harness’s for the clock and volt meter where The S had one feeding both instruments. The RS has unique wiring for the fairing incorporated into the main wire loom.
-ign switch on an RS was in the cockpit area above the gauges (between voltmeter and clock), not on the headlight (which would have been fully inaccessible).I have a 75 R90/6 that I installed a RS fairing on and left the switch in the headlight bucket. It would be to much trouble to move to the cockpit area. There is no problem with access to it.Don


Originally Posted by bikerfish1100 View Post

-ign switch on an RS was in the cockpit area above the gauges (between voltmeter and clock), not on the headlight (which would have been fully inaccessible).I have a 75 R90/6 that I installed a RS fairing on and left the switch in the headlight bucket. It would be to much trouble to move to the cockpit area. There is no problem with access to it.


okay, forget the “inevitable”, and replace with “a wee bit annoying”. That about right?

Ride Safe, Ride Lots
-Thanks so much everyone, this is really helpful. Yeah, I was thinking that this was a 7 adjusted with the luftmeister fairing. The number on the frame is 6141650 R100/7, so this seems to hold with the idea that it is a 7 with a Luftmeister fairing. Thanks for that angle, I was confused, obviously! This is fun though, it’s like a mystery. Do you guys have a recommendation on where to get a new wiring harness? I would like to start fresh, or should I just run wires in from the turn signals and forget about the oil and voltmeter indicators? I guess I’m just confused about the relay set up if I run those things in independently…thanks a bunch for the input so far, it’s super helpful!

Very useful links for background on the BMW R series motorcycles

For wiring on BMW bikes, I’ve found several resources to be quite handy. On the ABC website there is a general color key for wiring on BMW bikes. See:

I like the large size color schematics from Prospero’s Garage. These schematics have a plastic coating so that greasy fingers don’t ruin the schematic. I obtained one of the schematics for each of my airhead BMW bikes. See:

Duane Ausherman has some good info on his website. See:

Rick Jones of Motorrad Elektric has lots of ‘lectrical stuff and his charging system book is very worthwhile. See:

A feller that goes by Snowbum has a lot of mostly text-based info on his website. This is a pretty useful resource. See:

Another feller, named Scot Marburger (aka Gunsmoke) has some very well illustrated technical articles on-line for airheads (more specifically the R100GS, but much is applicable to the /7). See: