So today while riding we came to the top of a hill with a two foot ledge and no good approach angle so I got close to the edge and went to pop my tire up onto the top of the ledge and I gave it some gas and let out the clutch. It didn't hook up like I needed so I tried again and as I went to give it gas and let the clutch out, the engine maded a clacking type noise and died. I didn't wrap it out it only briefly raised the rpms before it died. I tried cranking it over and it went a rotation then stopped..... When I got home I was thinking snapped cam chain balled up in the bottom end. I pulled both side covers, but first the ignition side, the chain was tight and no filings in my oil that onnly had 30 mins on it. I pulled the whole right side cover thinking that it might be something on that side and the same thing thte oil that I saw was clean and not bad at all, and I could spinig the engine backwards until it got to the bottom of its stroke. So I'm thinking that I dropped a valve and its stopping the piston at TDC and then maybe one of my cams is hitting something that is messed up in the head and stopping it at BDC. I won't have time to tear the head off till next week but I was hoping to pick some of your brains with thoughts or suggestions before I get to the point. i can't think of any way to cam chain could ball up and not look ok. As well I can.t think of anything else that would make the piston stop in its stroke at TDC and BDC or just short of each, its kinda hard to tell when you can't make a full rotation. Either way I'm thinking that I'll be replacing a cam chain its due for sure. I've already got 30 hrs on it this year. I'll probably install my big bore kit and the WR 1st and 5th if I'm going to have it apart. I just hope if it is valves that I don't have a messed up head like some of the similar situations that I was reading about on here. Thanks guys!!!