I have some Robart retracts that are installed in a top flite AT-6 Texan.
I get two or three good cycles from a full tank, and then its a long shot
for them to recycle again. Actually one will recycle 3 or 4 more times
after that, but only one. How many cycles should I get from a full can
of air? I can't find any leaks. Thanks, Aframe2

I get about 6 from the 605 retracts before they get very slow.  I'm still working on the wheel doors, so I dont have the cycling perfected, but in trail tests after about the 6th cycle I need to pump it up for them to cycle in any time frame, otherwise they take forever to open or close.

Sounds like one is a little sticky. This happens sometimes when the rails they are screwed to are not perfectly level.

4 to 6 seems about normal with 100 pounds of air in the tank. I mix up a stiff batch of soapy water and use a small paint brush to check every line fitting and the filler valve.

If you don't find any leaks, 3 to 4 cycles is not a problem, you should be pressurizing the tank with each flight to ensure you have sufficient pressure regardless, at least that's the way I fly my planes that have air retracts