scott14

My Ryobi is the 2-ring version, and the rings are pinned.... Can I safely mill out the exhaust port bridge?

I'm thinking with a larger carb and possibly a larger intake/reed valve the bottleneck will be the exhaust port.

Please... let me know your thoughts.

Orvie6

I may be wrong, but I would think that if you wanted/needed to increase the area of the exhaust port, you could mill out the SIDE of the exhaust port and leave the bridge in place. DO NOT touch the top or bottom of the port..just remove the amount equal to the bridge area from the sides of the port.

BillS

Scott,

You may already know that the port timing can be increased up to .035ā€¯ by removing or using a thinner base gasket. In the days of motorcycle racing it was not unusual to run with a single ring. It was also not unusual to shave the top of the piston in the exhaust port area to increase the opening time of the exhaust. Reversible changes seem like a better starting point for experimentation. I left the air box on my engine to prevent the loss of fuel charge. I have not experimented yet but did briefly turn one of my Ryobiā€™s 11,000 to verify that the magneto system was not RPM limited.

Good luck.

Bill

pdillon

Scott I was told that you needed x-many in/lbs back pressure on your valves/reeds to keep from burning the engine up .Please be careful. PHIL