300EX crank in 250X [Archive]

DAN@RAYWILT

11-14-2005, 12:49 PM

Please Help.. I am trying to find out if a 300 ex crank will bolt right into a 250x case. If not, what modifications would be necassary? Any input would be greatly appreciated.

Dan
:macho

roadthrills

11-15-2005, 08:04 AM

I know the 300ex crank has a starter ring on it, and possibly a longer snout. I don't think it will work.

bradley300

11-15-2005, 08:25 AM

it is also a longer stroke, so you may need to trench the cases if everything else works

DAN@RAYWILT

11-15-2005, 01:56 PM

see what throws me off is that the 250x and 300ex is the same engine besides the stroke. I work at a parts store and the 250x and 300ex calls for many of the same parts such as pistons... I am thinking the difference may be the length of the connecting rod. Any input to the? Thank you

Dan

wilkin250r

11-16-2005, 05:41 PM

No, they won't drop in.

The journals are different lengths, to allow for the starter gear on the 300EX. It would require EXTENSIVE modifications to fit a 300EX crank into a 250X, and these aren't modifications you can do yourself. You couldn't even send it to your local machine shop, the precision and tolerances required for crank work are very tight, and needs to be done by an experienced crankshaft shop.

It would be an expensive process, and I doubt anyone would even accept the job. You'd be much better off just buying a 250X crank.

Why are you asking this question? What are you trying to accomplish?

DAN@RAYWILT

11-16-2005, 05:45 PM

Well, I was told by a friend that this may be a possibility, I HAVE THE X FEVER! lol I love my old 250 and i want to get some more umph out of it... that would have been nice i believe i may just go with the powroll 330 kit.. thanks.

Dan

bradley300

11-17-2005, 06:36 AM

you'll like a big bore kit better than a stroker on that motor anyway;) i suggest gthunder's work they have a 350 kit (300ex) wich is 330 for a 250

DAN@RAYWILT

11-17-2005, 06:38 AM

thank you all for your input.. now i just have to fork up close to a thousand for the work lol... But at least i didnt just jump right in and try it...

Dan

bwamos

11-17-2005, 08:01 AM

Originally posted by bradley300
you'll like a big bore kit better than a stroker on that motor anyway;) i suggest gthunder's work they have a 350 kit (300ex) wich is 330 for a 250

Agree 100%. Torque isn't a problem for the 250x/300ex you want more HP. Keep the stock stroke and go with an 11:1 comp big bore.