My apologies in advance...
I was reading comment on case volume vs. displacement, and thought I would throw my 2 cents in... I am a liscenced mechanic with a Red Seal certification, so I'm not pulling theroy out of my a##...
Case volume does play a part in engine design, as does airflow and of course, port timing, squish, compression,, etc, etc. It was noted that the case volume of the CFI-2 is lacking, and perhaps it is minimal, but it is working and meeting current EPA regulations. Back in the day, we used to build stupid Rotax 740's & 760's, all were case ported, no two ran the same, and all burned a crapload of fuel. Different rotary valve timing, port height, squish were all over the place between builders (up here, anyway). I believe that airflow and atomization play a larger part then minimal differences in case volume, along with port height, size, and shape. There is more then one way to skin a cat, and I can honestly say I've never had an issue with Kelsey's stuff - on either my doos or cats. If he was building a 660 kit for the 600 CFI-2, I would likely have one in my wife's sled just based on past experience with his products - it has been my experience that if he isn't happy with the end result, he doesn't sell it, period. A bunch of vendors have come and gone over the last 15 years, yet RK Tek, SLP, Carl's Cycle (and a few others) are still here - that says something about the products they design and sell... No pissing contest here, just simple facts.
