Thanks BrendAn,
your right but unfortunately I’ve scoured their website and others including 20years of magazines which didn’t turn up the answers I was chasing. May cam grinder can’t answer it either so the only way forward is someone that has data or records of the operating paremeters of their engine which would help me greatly in making the right decisions. Yeah a lot of the gyronaughts are on ej22 and 25’s now with good success, again their still heavy and ide thought they would struggle to make the empty weight of 250 kgs without sacrificing fuel capacity. If I do that I’ll put my rotax 912 in.