Some of the Ryobis come with very short exhaust timing and definitely respond to more. The only way to do it right is to get a degree wheel and check it out. Shoot for around 150 degrees. Go slow, and take off a little at a time and keep checking the timing until you get what you want. Then be sure to chamfer the port edge slightly so as not to damage the piston and/or ring.

AV8TOR