RE: Goldberg 67" Yak 54 ARF
Aerobat55 I don't think your prop is large enought too pull the plane.In saying that I think you are under power with the Saito 125.Only my thinking, I have A Saito 150 in mine but I haven't got too fly it yet and i my still be under power my self i don't know yet.They are flying this plane with A 180 i hera and it is doing great they say.The big cowl on the plane needs A biger prop too get the pull it needs only my thinking.I have A 17x6 on my 150 Saito and it is turning it 9000 and running rich as it is A new Black Knight Saito.Hope this helps .
Joe