First guess would be that one valve is not closing and sealing properly. There is a possibility that you only partly unstuck the one you worked on, or the other one was sticking also, and one of them is stopping almost closed rather than completely closed. The seat may also be corroded and not sealing. Unfortunately since the engine is a Honda it presumably has the decompression device that holds one of the valves partly open until it reaches 600 rpm, so you can't easily test the compression.
You can find which valve does which which job by tracing the ports under the valves. They should be easy to see, just trace the exhaust port by continuing the exhaust pipe in the direction it's running, and seeing which valve it lines up with. It is important to know which valve is leaking - the symptom you've described sounds more like a leaky exhaust valve, but depending on circumstances it could be either valve (or both).
Did you adjust the tappet clearances accurately? A tight tappet means a leaky valve.
If the engine wants choke all the time, it is running lean, either because it has a carburetor/fuel supply fault, or because it has a leaky valve, or something else, that lets air or exhaust into the cylinder.
Last edited by grumpy; 06/12/10 02:41 PM. Reason: Expanded possibilities
