Well, I finally found a vintage Beemer. It was fully restored, but has been registered "non-op" since 1993.
It was running beautifully on my inaugural ride up the coast. Had lunch, got back on and about 4 miles later the left cylinder lost compression and started making a racket (ugh).
I stopped and called AAA to bring me home. This morning I popped the valve cover off, and saw the exhaust spring in 5 or 6 pieces.
Next step is to pull the head and see if the piston or cylinder is damaged.
Anyone had something like this happen to them? I could use some advice, this is my first airhead.
At this point I'm inclined to pull both heads and have new valves/springs installed. If these are the original springs, they might just be too old.
Previous owner had the engine rebuilt with new pistons, rings, valves, etc. but I'm not sure if he replaced the springs.
The exhaust valve feels a little sloppy in the guide, also not sure if this is normal or not. Also not sure if the valve was contacting the piston, but will know once I pop the head.
Feel free to chime in if you have advice or ideas! I'm fixing it regardless of what it costs...