Tom's slight slip in referring to a "compressor tester" is a well-deserved typo, obviously brought on by fatigue from having assembled and disassembled his bike multiple times in what seems like the last few days, but it got me thinking. If you did not have a compression tester, but did have a good air compressor, it seems you could run a pretty good compression test by pumping air into the cylinder with a spark-plug bodge while adjusting the pressure shut-off valve on the compressor while observing the results for different settings. Most garage compressors with tanks will go up to 125 PSI. If the cylinder will hold that, or maybe even less, then you could be pretty sure there is no bent valve or dramatic ring problem. However, now that I'm hallucinating about it, I'm not sure both valves are closed at BDC, where the piston will end up upon pumping in air (and there are probably other problems with this idea that I'm not considering, but it's too late to stop writing). Yes I know I could look it up, but I'm already procrastinating work by typing this.
Richard L.