I have an "Upbeat" in at the moment, non starter, checked and compression was well down, checked valves and they were both closed up. Reset and it fired up, however was really bad to get going again. Cleaned carb out, some water in float bowl, so drained the tank cleaned carb out and it was even worse to get started, checked the spark and it seemed very poor, no better with a new plug. As they are dirt cheap I got a CDI and coil off eBay, fitted the CDI and got a much better spark, however I could tell spark timing was well out as it tried to stop the starter when coming up to compression with plug lead on, but not when plug lead off. Put a strobe onto the engine and found timing between 20 and 30 degrees out by the timing marks. Put old CDI on and timing was bang on right. So, have I got a new CDI with faulty timing or do Upbeat "do their own thing" regarding CDIs and timing? It looks like the standard rectangular 5 pin plug, AC CDI but doesn't use the standard Honda wiring colours, for instance the kill wire isn't the normal black/white.

 

Both valves closed up means nothing at all. If the valves are out of tolerance and it tight it is very difficult to get started. Valves being closed on the compression stroke tells you nothing

 

Valve clearances closed up. Didn't think I had to point that out.