I just took the bike for a short ride. When I started it was hard starting (unusual) then it blew a lot of smoke (not unusual for being on the side stand) But when I left the shop I had to visit it was harder to start and then would only run on one side. I barely made it home on one cylinder. I took the valve cover off and pulled the spark plug. The exhaust rocker was about a quarter inch from the push rod. When I looked down the spark plug hole I could see something round where there should be nothing. Did I just drop a valve seat? Do I need a new bike? It is a '82 R100 with 180k.