Zeda Engines - Differences

[Rusty_S85]

Well I took my jug to work today with my $25 battery powered dremel tool. I knifed the transfer ports at the bottom at the crank case area. I then used a reverse cone burr bit and smoothed out the ridge on the transfer port as best as I could still not smooth but didn't want to hog on it too much.

I didn't do nothing to the intake or exhaust port. I did grind a sharp corner out of the exhaust port at the cylinder itself by smoothing it in at an angle.

Aside from that no real port work done. Not sure I really want to try widening the ports or not. I cant get my caliper in the jug to measure the width of the ports anyway.

As of now measurements I took at the mounting surface is that my oval intake port is 22.7mm wide. My round exhaust port is 20.85mm wide.

I am not sure if I can push the exhaust port to 24mm wide and might not be able to on the intake. Think I will have to wait till I get my reed valve and order my MZ65 exhaust so I can see what I have to work with for port matching. Hate to hog the jug out to 24mm oval and I cant match the exhaust pipe to that oval.

 

[Street Ryderz]

Well I took my jug to work today with my $25 battery powered dremel tool. I knifed the transfer ports at the bottom at the crank case area. I then used a reverse cone burr bit and smoothed out the ridge on the transfer port as best as I could still not smooth but didn't want to hog on it too much.

I didn't do nothing to the intake or exhaust port. I did grind a sharp corner out of the exhaust port at the cylinder itself by smoothing it in at an angle.

Aside from that no real port work done. Not sure I really want to try widening the ports or not. I cant get my caliper in the jug to measure the width of the ports anyway.

The quick way to messure the windows is to use a peice of paper curled up to slip inside the jug and make depressions by using your fingers to press the paper around the edges of the window then messure when the paper is removed and laid out flat.

 

[6blueoval9]

Well I took my jug to work today with my $25 battery powered dremel tool. I knifed the transfer ports at the bottom at the crank case area. I then used a reverse cone burr bit and smoothed out the ridge on the transfer port as best as I could still not smooth but didn't want to hog on it too much.

I didn't do nothing to the intake or exhaust port. I did grind a sharp corner out of the exhaust port at the cylinder itself by smoothing it in at an angle.

Aside from that no real port work done. Not sure I really want to try widening the ports or not. I cant get my caliper in the jug to measure the width of the ports anyway.

Just roughen up the intake port and smooth out the exhaust port then polish it... Don't polish the intake port.

Hogging out ports just raises the rpm and fuel needed for the motor to make the added power..Unless you going for a speed demon I wouldn't worry too much about it.

Stock ports can already support over 40mph as is... Just enhance them for efficiency... In alot of cases less equals more.

 

[Street Ryderz]

As of now measurements I took at the mounting surface is that my oval intake port is 22.7mm wide. My round exhaust port is 20.85mm wide.

I am not sure if I can push the exhaust port to 24mm wide and might not be able to on the intake. Think I will have to wait till I get my reed valve and order my MZ65 exhaust so I can see what I have to work with for port matching. Hate to hog the jug out to 24mm oval and I cant match the exhaust pipe to that oval.

Your opening the window width to 24mm the port outward to the flange should be opened to a max of 1.15 x the window so if the window is 24m across and 14mm in height thats the eqivalent of a 20.5mm dia and then if at the flange the port is 20.85mm it's perfect!And still could be opened to 21mm and work even better at making torque,The jug I've been running the past 4 months has an exhaust window width of 31mm and height of 15mm and the port at the flange is 28mm across and 21mm in height and ran at 165 p.s.i for just over 1000 miles now and still running strong!

 

[Rusty_S85]

Intake port is 22.71mm x 15.23mm oval. Exhaust is a straight up 20.85mm round.

I will have to see. I have to put this engine off installation for a couple weeks as I need to get the exhaust, windowed piston, and the carb before I can make my final setup.

Aside from that, I have to see how the reed valve sits in the intake port. I was going to smooth the intake port out and polish it up a bit as I know with 4 stroke engines port work involves polishing and removing anything in intake and exhaust ports that can cause turbulence the creation of turbulence results in the air/fuel mixture slowing down and allows the fuel to become unsuspended. For such a short port it might not make a difference to polish or not.

 

[Rusty_S85]

Made some paper diagrams of the ports they are as follows.

Intake : 21.31mm x 13.81mm
Exhaust : 21.59mm x 14.66mm

So for intake i need 1.345mm on each side to reach 24mm. Exhaust is 1.205mm on each side to reach 24mm.

 

[Rusty_S85]

Well i got the port work done. Have to make another port template to see the width now but using original pattern and adding proper measurement on each side should have me very close to 24mm width on intake and exhaust port.

Ok new measurements below.

Intake 23.35mm
Exhaust 23.52mm

Not sure if its worth porting some more to get it to 24mm exact or if its close enough.

 

[FurryOnTheInside]

Well i got the port work done. Have to make another port template to see the width now but using original pattern and adding proper measurement on each side should have me very close to 24mm width on intake and exhaust port.

Ok new measurements below.

Intake 23.35mm
Exhaust 23.52mm

Not sure if its worth porting some more to get it to 24mm exact or if its close enough.

Jaguar's dragonfly site gives the figure as 24.5mm so yes I would (and did) go further (with piston ported engine) but no idea if what I did was correct! I have widened the top of exhaust window and bottom of intake window and lowered the bottom of the intake window but on a piston ported engine. I don't know what the best intake window shape is for the reed valve engine.

 

[Rusty_S85]

I went a bit further after that post. Im currently at 23.87mm intake and 24.24mm exhaust.

 

[FurryOnTheInside]

You can add width but you can't take it away.

You can buy a new cylinder and start again though. hehe.