Mastermind
Work Saw Specialist
My friend Wes (wyk) has prodded me about doing an Echo CS-520 because it's a clamshell design. He evidently thinks I'm afraid of such things.
Well.......as luck would have it one of our members asked me to do a woods port on one of these little saws.
I have to tell you guys when I pulled this saw apart and put a degree wheel on it I was surprised.
The biggest issue with a clamshell. The damn things must be totally taken apart to get to the goods.
How many clammies have you seen with closed quad transfer ports???
The port timing duration on the intake and exhaust both were in the upper 140°s with 20° Blowdown.
I added 10° to both and raised and widened the upper transfers. I didn't touch the lowers.
I opened up the windows in the piston some....
After widening the exhaust I added an expansion step.
Well.......as luck would have it one of our members asked me to do a woods port on one of these little saws.
I have to tell you guys when I pulled this saw apart and put a degree wheel on it I was surprised.
The biggest issue with a clamshell. The damn things must be totally taken apart to get to the goods.
How many clammies have you seen with closed quad transfer ports???
The port timing duration on the intake and exhaust both were in the upper 140°s with 20° Blowdown.
I added 10° to both and raised and widened the upper transfers. I didn't touch the lowers.
I opened up the windows in the piston some....
After widening the exhaust I added an expansion step.