How low? Just ported a 660 jug last night. The darn jug had a huge lip on the bottom of the intake port. When I checked stock #s the lip was there making it look higher. After cutting squish and base I have the exhaust just where I want it but after porting it and removing the ugly lip it's now at 90° on the intake. Didn't run it yet. Hopefully it didn't hurt it.I could have gained a little more compression.......but that would have meant lowering the intake further. It's already lower than I really would like to see it.
Because her husband has crystal balls????
What does this mean in english ?85 is where the 661 is at after machine work.......and without touching a burr to the port. I like to see about 40 degrees of primary compression. The 661 ends up with 35.
When I have a port that is at a height I consider too low, or high, I will not widen that port at all either. We gain time/area in two ways.....either by adding duration, or width.
85 deg before top dead center is where the intake port starts to open in direction of engine travel. 35 or 40 would be its gulp of air fuel from tdc to closing of intake port correct?What does this mean in english ?
I have not a clue ,that's why i give the monkey 300 bucks to do it85 deg before top dead center is where the intake port starts to open in direction of engine travel. 35 or 40 would be its gulp of air fuel from tdc to closing of intake port correct?
My saws do not have push rodsBrian, just think of a port working like a cam, except the opposite. The width of the port is like lift, and the height of the port is like duration.
AAA
AAA...........YES thats the new stihl concept but you must wait a .............. little. Just the 63cm bar cost 400 euros , also its not 661 its a 441 with a on-off switch, some carbon covers and carbon handle. nothing special, when they make a carbon crankcase then its a special now its only a carbon covers.
Got the 35-40 wrong for primary compression. Im with Brian what do speak of master? Spent 5 min staring at a degree wheel moving it all over and couldn't figure it out.
Gotcha!This whole process gives us 5 points, or specs to consider when building a two stroke, piston ported engine.
1: Exhaust Height
2: Transfer Opening Point
The product of the interaction of those is 3: Blowdown.
4: Intake Closing Point
2: Transfer Opening Point
The product of that interaction is 5: Primary Compression.
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