donkey doctor

hello, no. 12 here; A piece of grit that held both valves open. It does sound like the intake valve isn't closing completely, now whether it's because of incorrect timing or the vlave not making a good seaI would drip some fuel into the inlet port and see if it leaks into the cc, past the valve, check the rockers to make sure the valve is closed before you do that. That'll tell you if it's the valve or the timing.