Yes,power on Ys engines is BIG!
But,and here is the "problem",
i have in my Extra a YS 53 FZ,and this damn engine doesn't work.
Em,sorry,it works well in idle but when you advance throttle to peak rpm,the engine slowly stops.
I checked all,needle settings,fuel lines except of the check valve!
So,i will not pay too much $$$ for an engine that will not work.
Ofcourse other YS engines like yours,are working as you said very well,but why i should trust any more this Japanese engines?
Also,i don't know how the new YS 63-S is working.
I have seen the YS 63 FZ working,reliably i think with tones of power.
What's your oppinion about installing the OS FS 70 Surpass or the new OS 70 FS ULTIMATE?
Also,the OS 70 FS ULTIMATE is lighter!