Hello everyone, im struggling with top end rebuild of ROTAX 127 from 1987 Aprilia Tuareg Wind. Piston and bore were damaged, scored enough to lose compression so i got it honed to oversize, ( note it has steel or cast iron liner in it ). It happened because of lean oil mix (i mix oil into tank, mix 1:50 which was maybe lean for this bike, i dont use mixer because it doesnt work. So i put it back together, got new gaskets, orings, piston (it was sized by guy who made hone) etc. But i got stuck because of the water leak into combustion chamber. I plugged cooling system back and filled up radiator. then I push starter button to let all bubbles out of cooling system but then destilled water (was used for testing only, i will put proper coolant when in normal use) after few rotations started to shoot from sparkplug hole (more like spraying dense mist). So i drained all the water out and put gasoline/ paint thiner to flush any water out of crankcase . This happened to me few times when I was tracing it back (i tried combination of silicone and base gasket) but I dont know where the problem is. I think I maybe miss some little thing I didnt know about.