Forum bmwbike.com

Hi,

I've got a 1955 R25/3 which hasn't been run in 10 years. It wasn't running when I bought it but the compression was good. I got a new condensor and spark plug and cleaned the points and it started and idles great.
It starts on the first kick when cold and drives well. But it gets grumpy when it's hot and will only start again (should it stall) with the throttle open. In addition to this, the top speed is about 70 or 80 km and it jumps with the throttle open at higher speeds.
Does this seem like an electrical problem? If not does anyone have any ideas what could improve this?

Thanks!

Robert

I would:
1. Replace the old spark plug wire and the spark plug.
2. Remove the carburetor and clean interior and the jets.
3. Check the points gap and the timing and adjust if needed.
4. Check the valves and adjust if needed.

Before going fast on an old bike that has not run in ten years, I would want to do those things. After that, going fast should not hurt it, and if it should not run well at speed, most of the possible causes have been eliminated.

Hi Robert,

My guess is that the fuel level in your carburattor is to high.
Make sure you have a float that weights 11 gram
and that your float does not leak.

A R25/3 should run at least 100 km / h

Good luck
Han Verhagen

Thanks for the suggestions!
I will give them a try.