seit 1981
since 1981

R100RT
1995

BK350
2002

CJ750
2003

R25/3
2004

A580
2005

KI120
2005

R51/3
2006

The BMW Singles from the 50's fascinated me for a long time. The clear streamlined bodies, the smooth engine and gearbox, shaft drive and of course the distinctive sound of the bike are always a feast for ears and eyes.
Unfortunately even the saddest looking pile of junk, is worth it's weight in gold in the eyes of the seller... So I had to keep dreaming about owning one.
Finding my R25/3 was a lucky coincidence. When we picked up the sidecar for the CJ at the warehouse I saw the bike standing right beside the sidecar. Intended more as a joke I asked if I should take this poor bike with me too. The guy selling the CJ smiled and said it would be a good idea, and he will ask the owner if it would be for sale.
It took nearly six months before the owner of the R25/3 called me back. He had bought the bike in Djakarta (Indonesia) and rode it there for more than three years. When returning to Germany he brought the bike home with him. Since the generator had some problems, he started to partially dismantle the bike while buying spare parts for it. We quickly came to an agreement and the 1955 R25/3 became the 2004 project in my workshop.

When I bought the BK 350 it was clear from the beginning, that it had to be a full restoration, for the R25 it was not so clear that I would end up doing the same. The day I put the bike in my workshop, I intended only to brush up the paint where necessary, fix the cabling and get the engine running. For that reason I created a test setup to be able to start the engine before going on with the work. The setup looked strange, but worked, I was able to start the engine. The foundation for what I wanted to do was there. But as usual, things develop different than you'd expect.

In Indonesia the BMW experienced some repairs and changes that could not be called minor anymore. But everything was done in a good and professional way, even though they did not have original spare parts for some repairs. First the bike got an anthracite paint job, then they put a modified R26/27 battery and air cleaner box on it as a battery case. Furthermore the complete generator was changed to a modern generator (maybe from a 80ies scooter). But they did a great job with it, you can't see the change from the outside. The ignition coil was placed under the tank, and the front fork was extended (8cm longer). I have no idea why they did this, but the bike handles very well as long as you ride it solo. With a passenger the bike gets tricky in the curves and no longer fun to ride.

Looking at this, the question came up in which state of originality the bike should be brought back. The answers came step by step. When I could not find the same paint to repair the scratches, I made the decision to return to the original look of the bike. I had the sheet metal sand blasted and repainted. A problem was the relatively fresh undercoating they had put on the bottom side of both fenders. The removal resulted in severe damage of the before not so bad fenders.
I did not intended to take the engine apart, but Rolf Gehrke, the Mechanical Wizard of the Einzylinder-Forum strongly recommended to do both engine and gearbox. That was the point were it was clear that the bike would undergo a full restoration, but not to its original state. I wanted to keep the longer fork, generator and special battery box. I simply like the looks of the new box better than the open battery of the original.

I had the generator re-magnetized, changed the old rectifier to a modern BMW /5 rectifier and put an original ignition coil back to its former place underneath the generator cover. To make sure that the generator was working properly, I made a test setup with a drill as a motor to turn the crank, and used an oscilloscope to monitor the output of the rectifier.

When the bike was finished it ran quite well, but the maximum speed was already at 75 km/h. To gain a bit more power I 'adjusted' the pressure conditions in the muffler by drilling some more holes in it. The second problem was the carburetor. The slider was worn out, and no matter what jets I used it did not improve its performance. After a few months of unsuccessful trying, I sent the carb to Richard Sheckler in Wayne, Ohio and asked him to try it. After a testride Richard decided to send the carb to Bruce Chessel in Woodstock, Ontario Canada to have a new slide made. After getting it back he adjusted the jets and sent it back to me.

Now the bike is running really well. At 90 km/h the limit is reached, but it is enough to cope with normal traffic. Since the first time Isabel (my wife) rode the R25. She really loves it. It is light and easy to handle compared to her CJ. It has turn signals and me as starter.