Hey guys (and gals too if any). I started playing with saw porting a couple of years ago and in my spare time I've been building saws. I really like the CS-490 and CS-590 for the value and ease of modification. In this video I demonstrate the difference between several of what I call "stages" of CS-590 builds. The Stage 1 is a deflector mod (remove inner rear-facing portion) and different carburetor nozzle. All other stages have these same 2 mods but cylinder changes also. The second saw is a CS-620 cylinder with a little cleanup of the transfers and widened exhaust port a bit but no port timing changes. The 3rd and 4th saws are different porting configurations on a 590 cylinder. I have a setup where I stagger the ports and run a little less exhaust advance for a bit more bottom end and a version that has different transfer timing and an earlier exhaust opening for a bit more top end. I plan to test the saws with a longer bar next as they are all almost running near redline with the 20 inch bar and my test beams. I really love these saws and they are a hell of a value even without porting. Obviously more could be had easily with more muffler opening, but the folks that buy my saws typically don't like them loud. Here's the vid, let me know what you folks think.....
