Repair/improving top transfer openings?

[BikeBuilder43]

Recently I did some port work and raised the transfer openings which exposed them more to the exhaust opening. Not good!! Never do that. I worked with a 2 part putty that hardens like metal...harder than jb weld. Could I use it to lower the transfers below the exhaust, even lower than factory and redirect them away from the exhaust. I know I'd have to put another gasket on the bottom of the cylinder to expose more of the transfers again.

 

[Deleted member 12676]

yes you can but don't do guesswork. use a degree wheel on the magneto with the head off to observe the total number of degrees the port(s) is open.
Exhaust port can be as much as 160 and the transfers shouldn't exceed 120 degrees.

 

[BikeBuilder43]

The degree wheel determins the height of the openings?

 

[Deleted member 12676]

360 degrees in one crank rotation

as piston goes down the port begins to open. mark the degree on the wheel and keep turning the crank. note when the port starts to close.
the total number of degrees the port was open is what is important.

 

[BikeBuilder43]

What about the width?

 

[Deleted member 12676]

I made the width of mine less in order to direct the transfer flow more toward the intake so that less is lost out of the exhaust port. That improved its power.

 

[BikeBuilder43]

Thats what I'm gonna do. Just wondering if lowering the ports so the top of the transfers arent in line with the bottom of the exhaust would yeild any power gain. Or maybe I could fill in the bottom of the exhaust port and take some metal off the top. It would raise the port and the transfers wouldnt be lined up with it.

 

[Deleted member 12676]

you are talking nonsense.
It is all about the degrees that ports are open.

 

[BikeBuilder43]

I know that. I was just thinking of changing the exhaust port location because I already raised the transfers too much.

 

[Deleted member 12676]

How do you know what is "too much" if you don't know the port duration in degrees?