What does an unsuported pinston-ring sound?

[Cruz_e_Silva]

Hi!
A friend offered me a Top cilinder but it came with a big exhaust port. I got a Top 1 ring piston for it and put it all in a BW's. The port is a little high and wide and I think it was made be a stupid young boy that thought that big and wide was the solution. Now the bike does a metallic noise that gets at high rpm. Could it be from the ring?
What is the rate of exhaust port width compared with piston diameter so the ring could be well suported?
The piston is a 47mm one and the plane exhaust width is 37mm.
Thanks

 

[Browni]

The maximal width is 34-34,31 mm with an oval port cylinder, if you make it wider it's not very safe. Is this cylinder comaptible with that piston? So is there cylinder wall at the piston ring's opening side?

Maybe you can save this cylinder but you have to make very big curve to the port sides, so you have to increase the port timing..

 

[roost]

That's too wide. Is surely nearly touches the transfers. It is not advisable to go over 0,7*Bore diameter. With such width, not only the rings will suffer, but also the piston will wear very quickly.
Weld an piece of iron in the exhaust and bore it to 47,6, then you have a cool bridged port exhaust.

 

[Browni]

That's too wide. Is surely nearly touches the transfers. It is not advisable to go over 0,7*Bore diameter. With such width, not only the rings will suffer, but also the piston will wear very quickly.
Weld an piece of iron in the exhaust and bore it to 47,6, then you have a cool bridged port exhaust.

Koso makes an iron cylinder with bridged port!

 

[Cruz_e_Silva]

First of all thank you all for your opinions.

Second there is piston wall at the opening side of the ring (between boost port and secondary port)and the piston is for that cilinder - Top Performances Racing (an old model).
Third my exhaust port is already like the one on the right.

Another question do you measure the width in a plain or directly in the cilinder? That is because in a port map the port appears wider than it really is on the cilinder.
That idea of welding is a bit to radical for my brain at the moment. But I'll think about it.
The cilinder is only 47mm not 47,6.

 

[Browni]

First of all thank you all for your opinions.

Second there is piston wall at the opening side of the ring (between boost port and secondary port)and the piston is for that cilinder - Top Performances Racing (an old model).
Third my exhaust port is already like the one on the right.

Another question do you measure the width in a plain or directly in the cilinder? That is because in a port map the port appears wider than it really is on the cilinder.
That idea of welding is a bit to radical for my brain at the moment. But I'll think about it.
The cilinder is only 47mm not 47,6.

in plain, so you make a portmap to a paper and measure it!

 

[Cruz_e_Silva]

ok i've already made that and the value I gave you was from a port map.
thank you.