Need Info On Building 250x..Help??

[JDsBusa]

I have an 87 250x, Its motor has seen better days. I want to go bigger. I am new to atvs, and need some help. I have been told the 300ex, and 250 share most parts, what is different the crank or rod?? can I use which ever and get a weisco piston kit for a 300 then overbore with this combo? I want to up the compression, but not to the point that it is a pain to get started..I am new to this forum, I will appreciate any suggestions.
Thanks Justin:confused:

you are right when you say that the 250x and 300ex share most parts. the only real difference is that the 300 has a little bigger engine and electric start. i don't know how big you want to go, but i have seen kits where you can get 330cc for the 300ex- which will also fit the 250x. i saw this setup in an ad in the back of dirtwheels from four stroke tech. they should be able to help you out and answer all your questions. thier phone is- 814.842.6159 and thier fax is- 814.842.9221. you can also e-mail them at- mdunlap@bedford.net. hope this helps


1997 300ex
FMF MegaMax II complete exhaust
K&N filter
Bandit front tires
stock 400ex rear tires
AC Racing bumper and swingarm skidplate
all black Maier racing cut plastic
N-Style gripper seat cover
black Scott Hurricanes
entire frame, a-arms, swingarm painted black
taillight, tool box, footguards, front brake disk guards, handlebar plactic, parking brake all removed

[JDsBusa]

Someone told methe 300ex had a crank that is 1.7mm longer,and another told me the rod was longer. ?? I dont know which it is. If it is one or the other I will do that, and then get a piston kit for a 300ex. I dont know if this will work, I guess I need to do some research.
Justin

[NJ300ex]

I think the 250x crank is different because its a kickstart. You can bore it .80 over and that will bring you to a true displacement of 298cc i think. The shops you will want to call are:

TC racing- http://www.tcracingengines.com/

Four Stroke Tech- http://www.fourstroketech.com/

Sparks Racing- http://www.sparksracing.com/

LRD- http://www.lrdperformance.com/

All these sites have thier phone numbers and email address on the site. They will offer just a bore and piston to full race mods. I suggest calling up each shop and telling them what riding you do, how much you want to spend, and how much power you want. Then decide who you want to use. All these shops are very reliable. Hope i helped.

[Giz400ex]

Don't forget about the 350x motor!!!! A friend of mine installed a 350x motor in his 250x frame and the thing is pretty sick!!! IF you find one it isn't going to be cheap but you'll like the results. Consider it!!