Vintage BMW Motorcycle Owners

Well, the BMW /2 crankshafts flex quite a bit at higher rpm's. BMW even had to use the barrel bearing in the R68-R69S because of this. I don't know if a roller bearing would be able to cope with this flexing.

The idle mixture screw regulates the air. Out is more air, thus a leaner mixture, in is rich.

But that really looks like oil. So either valve guides, piston rings or a damaged head gasket.

Average size of a German man in 1960 was 1.79 meter. So there is your answer.

First, your R50 has a magneto ignition. It is totally independent of the battery. I guess your high tension leads are stripped a bit too long, with the copper touching or almost touching the cover where they are connected to the coil. Or it is some silly little thing like you forgot to press down th...

Thanks for the kind words. Regarding the brake, it probably will be a standalone brakepedal with hydraulic actuation of the sidecar brake. The integrated one like it was originaly from Steib would be wunderfull. But they are crazy expensive and I don’t think you can buy spareparts anymore. Especiall...

Next up is the body. Here I really want to make it all from scratch. Just because it should be possible. Without any real experience in this field, I had to purchase some tools and rearrange my little workshop. https://i.imgur.com/kVu2Y6h.jpg I made a wireframe, first the front half of the body. htt...

It's almost a year now, and I have been tinkering quite a bit since then. To show that my request wasn't all hot air and no substance, here is where I am at the moment. I use a Chiang Yiang frame. It allready has a nice torsion bar suspension. It has the same overall dimensions as the Steib but all ...

In my R25 I used a KS piston with 0.05 mm clearance. I got a piston seizure at 600 km. Of course, the singles are more vulnerable, cooling is not as good and you tend to run them at full throttle more often. Now it has 0.07 mm clearance and no problem so far.

On my R25 the rubber puck doesn't touch the bell housing. You should carefully check if everything is still properly tightened. Especially the nut in the cardan coupler could come loose. Or the threaded ring holding the pinion tight into the casing. I don't know if this would cause a similar problem...

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In 1957 al the bikes came with the standard gear ratios. That is 1st gear 5.33:1.
In 1958 all the bikes came with the sport gear rattios. 1st gear is 4.17:1