I've been having issues with the petcock on my R25/2. When the knob was turned off, there was still a dribble of gas. That resulted in a bit of a leak at the bottom banjo fitting that brings fuel in from the bottom. So, I figured I'd better overhaul the petcock. For all I know, the parts in there are 65 years old!

I asked some questions on a German forum specific to the singles. Since not many of the single cylinder bikes made it to the US, I've started conversations with them...they've been very helpful. So, much so, that one of the guys offered to send me the internal cork needed for the carb! He had overhauled the petcock on his R23 and he had an extra. That was really wonderful of him. Took 3 weeks for the letter to get here.

So here's what my petcock looks like. There is another style that has the appearance of a "bullet"...the internal cork is cylindrical. Mine is flat.
Petcock.jpg