Did a valve adjust today. double checked everything. Fired it up and went for a ride. Got about 6 mi. and those valves were really singing. Tried loosening the decomp. a bit nothing. got it back home and DAMN, the left intake tappet and nut were gone, no wonder it was so loud. Anyways got the parts out and i will do it again, but this time check it 3x. If that had been on the cam side it could have been disaster. So if you think you checked things over maybe it is not a bad idea to check once more.