combatpilot said: Yea i dont know whats going on here either. tell ya what i will mail you a waist cut reed and you mail me the bean cut reed and we can each try these and see if we get the same reults again. I am wondering if it would be worthwhile for you to do your test again. I had done my reed valve twice and got two different results to.
Well... I too thought it would be interesting to exchange reeds to test, but you know, It seems that we've both come to the same conclusion, that modifying the reed or reed clamp does little or nothing for the performance of the Ryobi. Although it might be of great academic interest, I'm of a mind to keep the focus on the original purpose of your post, and that is to determine, albeit by trial and error backed by "educated guesses", what tricks and mods can be done to make the Ryobi as good as possible. I admit to having too many projects in the works and I'd rather spend the time on forging ahead with some of those than chase a configuration that might make us smarter about the operation of reed valves but not contribute to the definition of the best setup for the Ryobi.
combatpilot said: The reeed valve has no effect on the transfer phase of the the cycle. this cycle starts as soon as the piston opens the transfer port and ends when the tranfer ports are closed by the piston. the only way to change the timming of this cycle is to change the intake port timming. I think what you are talking about is the lower end compresion cycle. true if there is a lag it in effect lowers the duration of the lower end compression cycle. this in turn creats a lower pressure differential and there will be less pressure energy to force or transfer the air and gas mix through the ports and into the cylinder during the transfer cycle when the transfer ports are open.
I agree with your analysis! I had not previously thought out that the piston is blocking the transfer ports until it is well on it's way down the bore and by that time the pressure in the crankcase has built up considerably, certainly enough the close the reed, one would think!
12.7 mm carb on the way. I'm already wondering if my exhaust system needs opening up. The 1/2'' EMT (electrical metal tubing) stinger has no more area than a 12.7mm venturi. You'd think the total exhaust exit area should be greater than the carb inlet area.
diceco