I recently changed the duck bills, toilet ball and seal and ball shaft cartridge on my 2 systems and they still cycle once in 7-8 hours.
I still can't find an answer as to how tight all the fittings for the duck bills should be perhaps if too tight they twist some and leak slightly. I did use dish detergent as a lube as Pascal had suggested on another thread but mine still cycles the same. I've tried different tightness on all fittings and clamps to no avail. I am considering giving up and putting it in sleep mode while I sleep, but I tend to obsess if I can't get things as they should be.
My thought is that if the complete system is sealed, toilet to vacuum generator, the pump should not cycle.
My latest thought is that perhaps the hose itself is slightly porous which would explain both odor permiation down stream to the holding tank and vacuum leak on the suction side. Fortunatly most of my system is rigid PVC with minimal odorsafe hose. Hose change out may be one of next years projects.
All that thought hurts, I need a nap now.....