Ok, ok, it sounds like some of us are talking about engine performance and the rest are talking about siphoning and leakage. All I wanted to know is whether the Saito 100 ran well in flight in the stock UCD 60 installation without Perrys and Clines and Iron Bays, etc.

Everybody who has a UCD knows where the tank is and that the engine is inverted and we know it leaks.

And yes my UCD 46 with its Saito 72 leaks while parked but it runs perfectly on the ground and in the air through any maneuver with no assistance from regulators or pumps.

I handle my siphoning problem a different way. Since the UCD 46 cowl covers my Saito 72, I use a Sullivan filler valve to fill the tank. This valve requires no special fitting to fuel it, just a short length of brass tubing. Between flights I just stick a plugged piece of brass tubing in the valve to block it. This is no more labor intensive that switching off the receiver after each flight.