Will a piston out of a 300ex work in a 250x.I am going to increase the cc's of my 300ex,my freind has a 250x was just wondering if the piston would work in in his quad?Thanks for any input.Daryl Also does anyone know what the bore is on both engines,or where I can find the specs?

 

Man am I surprized,I thought someone could help me out on this question because so many people on here have built engines!Daryl

 

Changing out the piston to a 300ex piston will work, but you will get no gain in performance, but possibly a slight decrease (the 300ex has a lower compression ratio than the 250x, which may caused by less dome on the piston). Both motors have the same bore, but the 300 has a longer stroke than the 250 does. I suggest maybe going with a 330 sleve (it will fit, but have under 330 in displacment, probably around 280 or so), a high comp. piston (11:1 is a good medium), and a mid-range cam.

 

The 330 kit on the X raises it up to 288. I've got it and I'm running 11:1 so I can still run pump gas. I say 288 is close enough to a 300 so I just call it a 300.

 

Thanks for the info guys!Daryl