Hi,

Well, that reverse rotation idea is at least worth running a few test runs in the normal rotation to see if it could be causing a problem. Many years ago I remember reading an article about moving the cylinder off center of the crank axis, and supposed gains in power achieved by doing so. I don't know if anyone is doing this in manufacturing, but if so that could perhaps cause a problem when run in reverse. I know often times auto engines have the pin in the piston offset a bit to lessen piston slap. If they are reversed, the engine will gain a touch of power at the expense of more piston slap noise. If your engines happen to have the piston pin thrust offset, this could also be a factor. These things might be difficult to measure, as we are talking thousands of an inch...

Just trying to throw ideas out there to help.... Good work on the extensive testing!

AV8TOR