I took a long ride yesterday with no trouble. it was raining very heavily for part of my ride. my ride was almost 40 miles round trip with no trouble. when I got home, I found a port matched intake gasket and swapped it out. I also tightened all my screws, nuts and bolts. it seemed to be running much better after swapping the intake gasket. but today on the way home from kmart, the engine cut out and wont start again. I put the other intake gasket back on, changed my spark plug, checked my wiring, still, no start. I took the head off to have a look inside. no score marks on the cylinder, but I do hear a pfft sound when rotating the piston. also, the head and the piston are completely back. I am running 5oz/gal and have been since after break-in. the throttle needle is leaned out as far as it can be.