250x engine rebuild Questions

[raven]

going to reuild my 250x what internal parts are diff from 300ex was thinking of using 300 crank,rod,jug, cam and maybe 11:1 wiesco bore .40??? need build ideas thx

[250X_project]

Jug and cam are the same so will work fine, but will give no upgrade.

The only way to use the crank/rod assembly is if you find a bearing to fit the 300 crank and also the 250 cases (not sure if this bearing even exists)

and if you can not use the crank/rod you also can not use the piston. Though Wiseco make the piston for the 250X only it actually has a 12:1 compression- must run at least 93oct(worked fine on mine)

any other parts? Hope I helped! ;)

[bwamos]

Also the kickstart wont work on the 300ex crank.

I really like the shorter stroke of the 250x, myself.

If you want some fun power go with an 80mm piston w/ bigbore sleeve, and headwork.

80mm x 57.3mm stroke would be a fun, quick revving, machine.

[raven]

my crank,rod and bearing is fine, my piston now is 11:1 bored 40mm its tore down because I threw a timing chain going to replace that and the tensioner and jug, cause I snaped bolt inside jug during tear down and dont want to deal with drilling it out. my friend will do all the work so that is free just need some info on what would be good build going to race flat track this year. I can throw around $600 into it need $ for rest of quad what would you recomend thx alot for the help

[bwamos]

So you have an 11:1 40mm on the stock stroke.

You have $600 to spend on the motor?

Easy.. professionally ported & polished, big valve head and a cam.