tree monkey
Addicted to ArboristSite
the transfers take more time then the rest of the saw. it's the most important part of it too. I widen most 4 port engines, but rarely widen a 2 port.
the main port is towards the exhaust, secondary towards the intake.
I widened the mains towards the exhaust port. I do this so I can keep the angle of the port angled towards the intake. I do my best to keep the tunnel the same width and height. a small taper is ok(wider at the base). on the secondary's, the port match didn't allow much room to widen the port. so I cut the port on an angle from the base to the window, and cut the web on an angle to match.