ORIGINAL: William Robison
Lengthening or shortening the rod, with no other changes, does affect the compression ratio. But I will point out that's far from the easy way to do it.
That'll work in a 4 stroke so long as the valves still clear the piston but if you do that in a 2 stroke then you'll also change the port timings. The easy fix there is to shim up the liner by the same amount you've lengthened the rod. Of course, then the compression is back to where you started so lengthen the rod a bit more. Then to fix the timings shim up the......uh oh...I think I see a problem looming here...
