Matt,
Sounds like the OS needs a compression release like we sometimes use on long-stroke Harleys. Is there any place on the head where you can machine a spot to put one in? You'd have to make a little tiny compression release device too but this may fix your problem.

That being said, the engine should start with a hand flip IF the ignition is firing at the correct time since you said it definitely has fuel (Spark + Fuel + Compression = Should run!). I know it sounds like a trivial thing but if the ignition system is an "auto advance" type it may not know where the piston is unless the engine has rotated a few times at a steady speed. I actually built a single-fire ignition for Harley engines a few years ago and I learned a lot about ignition sytems and how they work. Some simply fire when they see an input from the crank sensor but an auto-advance type is more complicated. Depending on how it's designed it may not be able to figure out exactly where the piston is under all conditions - especially when hand-starting. On the one that I built I used two hall sensors and a wheel with notches in it. This gave me two pulses per cylinder - one was at 45 degrees BTDC and the other was at TDC. To get the advance curve I delayed by a certain time after I saw the 45 degree pulse (timing was never more than 45 degrees BTDC) but to get the thing started I couldn't use this method. The reason being that converting between "degrees" and "time" will only work when the engine is running. The trick was to use the other pulse at TDC: I ALWAYS made sure the coil was triggered at this time. Until I figured this out I had lots of trouble getting engines to start because big Harleys tend to crank fairly slow. This may explain why you're having so much trouble hand starting the OS. Not knowing how they designed the ignition system I can only point this out as an FYI - it may not even apply to your situation.

Doesn't Ed have one of the gear-reduction starters with a LiPo pack attached to it? That may be all you need. High-voltage on a Dynatron is OK but as you've seen it doesn't always work. The gear-reduction types generally work better at starting the stubborn high-compression stuff. A 4S LiPo pack on a gear reduction starter (Kavan, Magnum, etc.) is pretty nasty!

John Pavlick