Thank you Crazy frog for the intro. Much appreciated.

I stay in Pretoria South Africa and have been riding the K100RS since 1986. First the 8v model and now the 16v 1991 K100RS which I purchased in 1996. I have done many trips and km's in SA and Namibia and still love my K as I did the first day I got it. This bike is 100% and everything functional.

All maintenance and repairs I do myself. A few years ago I purchased, for spares, another 1991 K100RS which was in an accident. During COVID, I decided to restore it. I got it running very well but the cosmetics still needs to be done. A lot of used parts family brought back from Germany.

This year I managed to pick-up another one, in good condition but needing a lot of tlc. Like ABS, vibration, cracked hoses, hard o-rings, high fuel consumption...lights. I got onto the forum by searching for info on resetting and testing the ABS components. I got some info but am still stuck so I'll be busy with that coming 2024.

All in all I now have three 1991 K100 RS, one charcoal and 2 Pearl White.

Kind regards and blessings for 2024.

Rolf Eggers

WelKome to the forum, Rolf. It is good to hear you are engaged in restoring the early K bikes. We're glad to have you here.

After a few more posts you'll be able to post images and gain access to the technical pages for members. When you get a mo', pop onto the Forum's Main Page, go to Profile, then Signature, and enter the year and models of the bikes you have. This, of course, makes it easier for other members to assist you in whatever issue you're facing.

Best,
Daz
aka TWB

hello Rolf

So you've got a large dose of K-pox then? Many of us have the disease!

Welcome Rolf

Hello Rolf. Definitely K-pox!

... and looks like there is not cure for K-pox. 

Don't have a problem with that. 

Welcome Rolf! Looks like you have been infected by K Pox like many of us!

Below is a doc for ABS 1 Troubleshooting that i use. Its pretty detailed and easy to follow.

ABS 1
Let me know if you cant open it and i can mail you a copy. For some reason i am not able to attach the doc here!

Thank you very much Curley,

I managed to download and see I'll need a BMW tester. and diagnostic. That I don't have. Any way around that? But I'll still study the doc.

Hi Rolf,

to our community!


Bernie

Looking for a dual bike (on off road). Today had a look at a 1996 K75 Ultima that is up for sale. Seems in not too bad condition but I'll need some guidance as this is the first time that I looked at, in detail, and rode the 75. I have been riding the K100RS for about 38 years. 

Its the naked Ultima with no frills. Basic and just about the same as the first 75s. The front mudguard is like my RS, in two pieces, and not solid as with the earlier versions. It has the three spoke wheels.

I must say the ride was totally different to the RS. I found it a little unstable or more difficult to handle. Nowhere near the power and speed but comfortable and NO VIBRATION. mmm For off road will need some getting used to. Off road ... trans Africa.

The mini fairing is too close to my head and interferes when wanting to place the bike on the centre stand or standing. The water pump is making a humming noise which, according to the seller, has done so for a very long time. All brake discs need replacing. Are there aftermarket available? Charge light is on dim, and the red warning light was on but went off after a while. Front tyre will need replacing as well as the battery. Clutch takes right at the very end and there is a lot of play on the throttle twist grip, Choke or fast idle is not working. Needed to top up with coolant and pump the tyres.

How can I show some photos?

EBC makes K brake rotors and I'm pretty sure that Motobins also has rotors.

It is a K75 Basic model with a low seat, City panniers, crash bars and the large clear screen specific to that model and the K100 Basic.  I think this model was called the K75T in some markets.  The handle bars I think were also specific to that model and were slightly different to the 75C bars.  

It also has the R series hand guards fitted as well which I have those on one of my 75s.  It is clean and tidy which is a good sign.  Are there any leaks from underneath the water pump, as there is a drain there (about 4mm) which if not dry will give and indication of a water pump overhaul.  As you live in Pretoria at altitude and away from the coast, there is no corrosion on the engine, gearbox and final drive.  

I have ridden a red one of that model around Europe about then years ago and found that I did not really like the screen although it did keep the cold off.  

It's a keeper.

Rolf E wrote:Looking for a dual bike (on off road). Today had a look at a 1996 K75 Ultima that is up for sale. Seems in not too bad condition but I'll need some guidance as this is the first time that I looked at, in detail, and rode the 75. I have been riding the K100RS for about 38 years. 

Its the naked Ultima with no frills. Basic and just about the same as the first 75s. The front mudguard is like my RS, in two pieces, and not solid as with the earlier versions. It has the three spoke wheels.

I must say the ride was totally different to the RS. I found it a little unstable or more difficult to handle. Nowhere near the power and speed but comfortable and NO VIBRATION. mmm For off road will need some getting used to. Off road ... trans Africa.

The mini fairing is too close to my head and interferes when wanting to place the bike on the centre stand or standing. The water pump is making a humming noise which, according to the seller, has done so for a very long time. All brake discs need replacing. Are there aftermarket available? Charge light is on dim, and the red warning light was on but went off after a while. Front tyre will need replacing as well as the battery. Clutch takes right at the very end and there is a lot of play on the throttle twist grip, Choke or fast idle is not working. Needed to top up with coolant and pump the tyres.

How can I show some photos?

I understood the K75 Ultima had the full works as in full RT/LT fairing, LT screen etc, ABS, panniers etc. so do pop up a photo when you can. I made attmepts to buy one at one stage but the one I looked at had a dud rear main seal and the price didn't reflect that so I left. Nice bike though and turbine smooth.

On to parts. I buy my stuff from two sources that are very good value www.kpartsholland.com are very good for used parts and also some new parts. There is also www.tills.de for new parts. For brakes EBC discs from Tills have been the cheapest I got for my K1100LT which will be same as your 91 K100RS. If you are looking for fairing parts K75RT K100RT K100LT fairing parts including the storage boxes and leg panels are all the same and interchangeable.

Attached are photos of the Ultima—the last of the K75 models. Produced in a limited production run, the silver with blue pin-striping seems to be its signature color scheme.




This photo is an extract from an Ultima catalog offered by Bayer Motorrad.

TacKler wrote:It is a K75 Basic model with a low seat, City panniers, crash bars and the large clear screen specific to that model and the K100 Basic.  I think this model was called the K75T in some markets.

It's a keeper.

Definitely a keeper. I have that model but it has a standard-height seat. I removed the windscreen and swapped the RT handlebar that was on it for a sidecar handlebar. The original seat was modified with custom honeycomb-structured foam within it that makes riding for hours more comfortable than the stock seat. For the 10 years I've owned it, this Brick has been a trooper over the rough roads I often ride and has never mutinied.

TacKler wrote:It is a K75 Basic model with a low seat, City panniers, crash bars and the large clear screen specific to that model and the K100 Basic.  I think this model was called the K75T in some markets.  The handle bars I think were also specific to that model and were slightly different to the 75C bars.  

The K75T came with a standard K100 headlight and was available from BMW NA.(North America)



It was a K75C with a C/Standard handlebars, windscreen, the K100 headlight and luggage. BMW NA did it to have a K75 model for LD touring. BMW NA stopped selling them in 1990 when the K75C went out of production and the K75RT came out.

Thanks for the encouragement and all the info.!   A trooper, I like that.

I see your bike Duck has side covers but the one I looked at just a clip-on tank / side cover with a centre bolt. Not sure if that means that the tanks differ? The tank does not seem to have the rubber grommet holes that hold the side covers in place?

Rolf E wrote:Thanks for the encouragement and all the info.!   A trooper, I like that.

I see your bike Duck has side covers but the one I looked at just a clip-on tank / side cover with a centre bolt. Not sure if that means that the tanks differ? The tank does not seem to have the rubber grommet holes that hold the side covers in place?

The tank is not different, the seat is. 

K75, K75C and K75S bikes do have a different tank from other Ks though. Those K75s don't have side cover grommets on the tank. Only k100s and K75RTs.

Low seat vs. regular seat:
https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/regseat/regseat.htm

Rolf E wrote:. . . the one I looked at just a clip-on tank / side cover with a centre bolt. Not sure if that means that the tanks differ? The tank does not seem to have the rubber grommet holes that hold the side covers in place?

To elaborate further from duck's post:
The side cover with a center bolt is half of a two-piece low seat assembly. It is part #1 in this drawing and indicated by the left arrow in the photo. This side cover is used exclusively with the low seat that is indicated by the right arrow in the photo. Low seats were designed to accommodate riders with legs shorter than those BMW considered average. Standard seats can replace low seats if parts are available.





My Brick has a standard height seat. Its side cover is attached to the cowl by a post at its rear that slide into a hole in the rear cowl (left arrow). A  flat spring with a slight radius in its length is designed to be  inserted into a bracket on the inside of the cover. The spring's radius bears onto a padded post welded to the frame behind the cover (center arrow). Two flat tabs molded into the top of the side cover are fit behind a flange on the lower side of the tank by pushing down on the cover then pushing the side cover tabs behind the flange and releasing the downward tension on the spring. The assembly is held in place by tension on both the tank's flange and the spring's tension on the frame post.


Finding undamaged examples of side covers I have described is difficult in the USA. They aren't in stock at MaxBMW where I do my parts buying. Get acquainted with MaxBMW's parts fiche to help you identify the parts you're encountering.