Does any one know if a 300ex cylinder just the cylinder can fit on the 250x?? the engines are the exact same as far as i know except for eletric start and a longer stroke and little bigger bore.... if the cylinder fits i will put it on my 250x and put the valve train of the 250x back on it... then i will bore that out and then get my botom end cut so the piston will fit in it... well then add the crank i already have waiting to stick in.. 12.5mm... thanks for the help...