Today I tested the changed Y-
Have to say I'm pleased with the results, I have defeated the Y-
I gained with widening the exhaust port and Chamfering the ports a sollid
Here you have four runs nicely to each other
26,3 till 26,5HP
Her one off the average runs with 26,4HP
Her the difference between the lifted Y-
Here you see the steps
Orange run -
Green run -
Yellow run -
The question remains.
What did what?
Widening the exhaust port with 0,8mm should normally gain power where already power is, but here it is revving higher.
Rounding the ports gives a better explanation, because you change the timing a bid.
Will investigate this further