I wonder if the stem from the broken valve is bent? I wouldn't go any futher. Sounds like you have to take it to the dealer and let them help you get a good story.Hope you know the dealer,if you don't be nice to them.I find I get more help that way(I usually don't get much help).If your bike is an early model,try and see if there was any late changes made to the motor. Good luck. Keep us posted.