Same here Kokamo, I've recently had by horizons broadened with Kawi Twin engines. I think if someone worked these it would raise the bar considerably.
You are right Jeff. I sell new riding mowers for a living and I get to experience how different new twin engines run being brand new. I sell Briggs, Kohler and Kawasaki. The Kohler motors are your typical twins...they do what they are supposed to do...they start, they run good, they mow grass. The Briggs motors are the same as Kohler, but they seem to be a tad smoother and don't make as much noise. The Kawasaki motors....they are an entirely different animal. They start up quick, they don't make any clicking or clattering noises, you can't hear the pre-ignition ping you hear in the Kohler motors, they have impressive throttle response, they have an impressive amount of torque as they don't bog down when turning on a 50+ inch deck....and they are dead smooth with almost ZERO vibration. Now you take all that from a Kawasaki and take in the advantage of the canted valves they have, slap in some ARC rods, an ARC flywheel, a precision cam, a little port work along with a bit of carb work, I would think that would be an almost bulletproof motor!
On the brand new mower I just bought only to tear apart to build a racer (CUB XT2), it had an FR600V 18hp Kawasaki. I've been saving this motor that has less than 5 min run time on it, in hopes someone will make performance parts for it, but I'm not holding my breath! I took the valve cover off and I'm impressed with the valve angles and they look like they could benefit a performance application. Kawasaki shows a max torque of 32.4 ft lb's at only 2200rpm....this is why it has awesome throttle response, but looking at the dyno graph, the torque curve is relatively flat across the full RPM range.....that gives me hope of a great running motor all around under a performance build with one of these motors.
I can't wait for go-fast parts!!