quick question

[TheX1992]

would a 300ex top end fit on a 250x bottom? i mean would the head bolts line up? its basically a bigger bore i was just curious.

[GT300]

I am almost positive that it can. The 300 and 250x engine are the same except the 300 has a little longer stroke. And the 250 is a kick start. Since the stroke is longer (about 8.2mm) it should fit. They both have a bore of 74mm.

[Ride400]

250x has a hotter cam too

why would you do that? The 250x has the better top end of the two. It has a hoter cam which actually makes it a little bit quicker and it accererates alot quicker. If I were you depending on wht you have it you have the top and bottom end of the 250 id just spend 150 bucks have it bored .30 over then put a weisco high comp piston in it and you will have a fast bike. All those statment are personaly opinions so dont quote me on any of them.
killer