1988 BMW R100RT

Front Brakes

On the way home, I decided that I didn't like how the front brakes sounded. At times there was a fluttering sound. When I went to pop the covers on the front calipers, I noticed that the calipers didn't match. Once I removed the covers, the brake pads on the left side were completely gone, while the pads on the right side were only about 1/2 used up. For those interested, the pads were BMW pads made by Textar. The rating was "FF."

Left Pads
Left Pads
(I really did ride home on these!)
Right Pads
Right Pads

And so, a set of brake pads was ordered to fix one problem. Also, I sent a email out to the tech mailing list associated with The Internet BMW Riders. Some things haven't changed in the last 20 years. I recieved several replies. Most of the replies said that there was nothing to worry about. There were a number of BMW's running around with only one front disk brake and they didn't have any trouble due to different side-to-side braking torque. One email made me actually look at the pictures that I took.

Left Caliper
Left Caliper
Right Caliper
Right Caliper (1984 or earlier?)

After a fair amount of research looking at parts diagrams and comparing part numbers, I think that the left caliper is original and the right caliper is actually a left caliper from an '84 or earlier bike. This seems like it would work just fine because the piston diameters are the same. However, the rebuild kits are different and I'm not sure what is different between the kits except price. Also, the brake pad wear was different left to right.

I now have a pair of calipers from a 1995 BMW K75. These calipers should fit and they will be a matched pair. Unfortunately, the pads will be another variety (about 1/8 inch wider than the current pads). These calipers will be inspected and rebuilt as well as being installed with new pads. All in time.

In the mean time, I have replaced the brake pads with EBC FA18HH. I know that I must be crazy to have gone from "FF" to "HH" rated pads. Time will tell if I like the pads. By the time I mount the "new" calipers, I should have a better idea as to which pads I really want to use.

I have already decided that I don't like the "HH" rated pads. As the pads have seated, the brakes have become very, very strong. I'm afraid that my skill at modulating the front brakes will lock the tyre up one day. That is how I destroyed my last BMW and I don't want to repeat that particular experience. The "HH" pads are doing a nice job cleaning up the rotors though.

One more brake problem. I finally checked the disks with a dial guage. Sure enough the right side disk was slightly warped. It was barely within specification, but I was feeling a surging in the fron brakes. This pretty much confirms that the right side of front wheel/brake disk/brake caliper was in some sort of accident.

Today, I did what "they" say not to do. I made an attempt to straighten the warped disk. I took a 1/2 x 3 piece of wood, about 12 incehs long and beat the disk into submission. I thought that I might get away with this because I would only be moving the aluminum disk carrier approximately 0.006". Slightly more than the thickness of a piece of paper. It worked to a point. I have significantly reduced the surging, but I have not eliminated it.

Once again, in the mean time, I have obtained a used pair of disks from an '88 R100RS to check out and potentially install. A project have I.


The seat never did fit quite right. So I attacked the seat with a Dremel tool and managed to get it to fit somewhat better. However it is still a little strange.

Shortly after modifying the seat an almost new seat showed up on ebay for a reasonable price. It does fit so much better. I am using this "new" seat without hinges. There are a couple of articles out there on modifying the mounting of the seat to avoid the hinges and their associated problems.


There is a crack on one minor part of the frame. When I get my welding skills back in shape, I'll mend it. However, I don't think that it will cause any harm to ride the bike.



The headlight only comes on when it feels like it these days. I think that there is a broken wire just below the relay connection. In true "Zen" style, I just put a nylon tie aroun the wires exiting the relay socket. It works perfectly now. Someday, it will stop working and I'll actually be able to find the broken wire. Until then, I'm happy.

Well, the headlight stopped working. The problem turned out to be the relay. As a bonus, the new relay has resulted in a brighter headlight. Go figure.


As I started to clean and polish the bike, I notice that the "surface rust" on the mufflers looked like it started on the inside surface. In other words, they will soon be rusted through mufflers. So, back to ebay and a set of used mufflers that were described as "not perfect." Well, they look new to me. So when the current mufflers do develop a hole, I will be swapping the pair out.


The starter has started making some noise that sounds like the bushings are dry. Soon, I plan on taking the starter out and having a look. If it is jus bushings, I should be able to replace and lubricate them. I had good luck with adding a grease fitting to a BobCat starter motor that sees a fair amount of abuse. I may try the same trick on this starter.


My funding for toys has run dry. Therefore, I really hope that nothing important breaks. In the mean time, I will be riding and enjoying my bike.