Throttle modification for YS system

The most important requirement is often lost to modify ordinary motor to YS fuel pressurized regulating system. Orifice effect in the throat while low speed operation should be removed to obtain stable rotation.
In order to do that, lower part of throttle valve must be opened freely when drum type throttle construction is invited, otherwise YS system would not demonstrate it's performance enough. So, the throttle valve must accept some irreversible modification, no return to natural aspiration.