I just put a new top end in my 1999 KTM 250 SX. Changed all fluids, new spark plug, clean air filter etc. My left side of the power valve broke. The gear that turns the power valve broke off but the right side is still in-tact and moves the exhaust valve fine. I started the bike up first kick and it started but ran really bad and had very inconsistent RPM. It ran for about 20 seconds, I tried to keep it running but it just shut off on me and it won't start now. My question is. Since the left side of my power-valve is broken, is that what is causing it to run terrible and why it wont start now? I am hoping the piston didn't get screwed up already. Maybe my spark plug fouled since the power valve is not functioning like it should? I just ordered the new power valve gear so I hope that's all it is.