so a couple of weeks ago I rejeted my carbs to 95 /125. I was having some issues with idling so I justed the air fuel mixture and also adjusted the large plastic knob on the carb which I think controls throttle speed. I never could seem to get the bike to run smooth. afterwards after I let the bike cool for a couple of minutes, I tried to start it back up again and I heard a loud clang... and then the fight wouldn't start. I also smelled something that seems like it might be burning plastic. after a little while I tried starting the bike up and if fired right up. I repeated this several times with the same results.. sometimes I would hear a loud clanb and the bike wouldn't start, other times it starts right up. is this something serious? any ideas on what this could be?