Husky_250
Husqvarna
B Class
Hi
I will measure these exhaust main/middle port dimensions later myself when I will take my cylinder off for some small transfer ports and exhaust ports finishing. I would like to know these dimensions if someone has measured them earlier or just has the cylinder off and could do it that would be great.
This motor has 72 mm stroke and the dimension ”Z” is 48 mm (from top of the cylinder to top of the exhaust port or actually power valve flap edge when it is in closed position and exhaust port is in it’s lowest height). This leaves 24 mm or one third left (72 mm - 48 mm = 24 mm) for the exhaust port height when I assume piston top is level with bottom edge of the exhaust port at BDC and piston top is level with cylinder top edge at TDC (zero deck height). But how much does this main exhaust port open with the power valve flap? What is the dimension when the power valve is fully open from cylinder top to power valve flap top?
Does it move lets say like 12 mm from 24 mm to 36 mm or even more? In the closed position with just 24 mm exhaust port height the exhaust port duration is only 120 degrees and this helps to make that very good torque. 36 mm exhaust port height in fully open position would be 180 degrees exhaust port duration.
It would be great if someone could confirm the true exhaust port height dimensions in closed and open positions. Also if you know if piston top is level at BDC with exhaust port lower edge and with how thick base gaskets it would help even more.
Thank you in advance! I will measure these later like I wrote above. But it takes some time before I will take my cylinder off.
Cheers,
Janne
I will measure these exhaust main/middle port dimensions later myself when I will take my cylinder off for some small transfer ports and exhaust ports finishing. I would like to know these dimensions if someone has measured them earlier or just has the cylinder off and could do it that would be great.
This motor has 72 mm stroke and the dimension ”Z” is 48 mm (from top of the cylinder to top of the exhaust port or actually power valve flap edge when it is in closed position and exhaust port is in it’s lowest height). This leaves 24 mm or one third left (72 mm - 48 mm = 24 mm) for the exhaust port height when I assume piston top is level with bottom edge of the exhaust port at BDC and piston top is level with cylinder top edge at TDC (zero deck height). But how much does this main exhaust port open with the power valve flap? What is the dimension when the power valve is fully open from cylinder top to power valve flap top?
Does it move lets say like 12 mm from 24 mm to 36 mm or even more? In the closed position with just 24 mm exhaust port height the exhaust port duration is only 120 degrees and this helps to make that very good torque. 36 mm exhaust port height in fully open position would be 180 degrees exhaust port duration.
It would be great if someone could confirm the true exhaust port height dimensions in closed and open positions. Also if you know if piston top is level at BDC with exhaust port lower edge and with how thick base gaskets it would help even more.
Thank you in advance! I will measure these later like I wrote above. But it takes some time before I will take my cylinder off.
Cheers,
Janne