I had an issue getting my FJ1200 to start. After checking how much fuel was coming out of tank, and not getting much, I took the petcock apart and it was stuck closed. Now I have to buy another one, but the local dealer cannot get me one. In the meantime, I put it back together just to get the bike running. After warming the bike up for a while, the idle started to get kinda high. After about ten minutes, the motor sounded different, (I cant explain) and the idle started to drop, then the bike stalled. The fuel light was on, but there seemed to be plenty of fuel in the tank. The bike did start right back up but I did not want to run it long in case there was something serious wrong. Does this sound like a serious issue or does it sound like maybe the petcock is just not working properly? Is there anything else I should check? Should I do a compression check on the motor?

Maybe the carbs just ran out of fuel, you really need to get the petcock fixed before looking for other problems