combatpilot said: I though of this to but the rubber reed valve you could open by merely blowing on it. it had no spring action whatsoever.
Yeah but it's got mass. I think there is a point where there is not enough closing force on the reed to overcome the reed inertia. The reed needs to reverse directions and get back down and close off the intake port so the transfer phase of the cycle can start. If it lags a bit there won't be as long a duration of transfer and performance will suffer.
diceco
edit: OH, SORRY. I MISSED YOUR POINT! You saw no change from stock to modified clamp plate to waist cut reed, right? Gee I don't know what's going on then. Maybe there is some distortion of the reed or a sideways twist or something on the reed with a bean hole in it.