While I wouldn't personally set out to build a Ryobi with a "slitted" cylinder, I have to admit that the one my brother has with the slitted cylinder runs well. It turns an 18 x 6 prop at 7700 rpms or so.

I measured the exhaust port width and came up with an approximate dimension of 62% of the cylinder bore. That should be small enough not to cause ring problems if you ground the bridge out of the exhaust port. Does anyone here have experience with doing so? Pinning the ring and then grinding out the bridge in the Homelite 25cc engines helps a lot.

AV8TOR