Ulf,
I am flying a 33% Cap at 23.5 pounds with a ZDZ 80. UNREAL performance.
Sure you can put a 100CC gasser in it but why add the extra weight when the extra power isnt needed.
Look at my website for some 3D videos of this plane and motor.
The TR and hovers in the clips are about 1/3 power.
Cap Vids