Sorry for the long post... This afternoon I went to fire up my XR650R after it had sat since the beginning of december. After about 3 good kicks it fired and I let it warm up for about 3 mins then as I set the idle it stalled out, happens sometimes if I don't turn the idle up enough when cold. When I went to kick it again I found TDC and kicked as per usual, heard an odd metalic noise and felt as if the gear or shaft slipped on the kick start. Now it will not restart. I have had this bike and ridden it frequently in all temps and elevations and never had an issue starting since i installed the edelbrock. I have a fair bit of small engine experience, but more so with 2 strokes. When i kick through slowly it now feels different, like I am now kicking through twice to hit what feels like TDC where as before it was once. (If that makes any sense). Also seems to have less compression overall as I can now kick it through repeatedly a bit like my KX250. Bike will not start no matter what. Does not smell of gas and has spark. Is it possible that the cam has slipped, or something to do with the decompression? a broken valve spring? I've owned the bike since may and the only modification to the engine is the edelbrock which was correctly jetted and ran great for the last 4 months in all sorts of temperatures and elevations, with no starting issues. Bike had about 1000kms on it. I am surprised as these bikes are known for reliability. Any ideas on what it might be before I tear into the top end?