250x Big Bore Questions

[ghak99]

I am looking into a big bore kit for a 250x. I am wanting to know how big you can take a 250x before the dependability goes away. An oil cooler case machining and race fuel is not a problem. I know the 288 bore is dependable, but how much bigger can you go without any problems? Has anyone used anything bigger and what about the 350cc bore?

[wwclea01]

Is yours a kick start or electric. I knew a guy that bored and stroked his and you can hardly kick it it has so much compression.

[ghak99]

All 250x's are kick start, I am not worried about getting it started.

[wwclea01]

You will be worried about getting it started when you cant kick it.

[wwclea01]

The last year they made the x it had electric start. It also had the secondary kick start also.

[ghak99]

I run 12:1 now with no problem at all.

[YZEATER]

wwclea01-- they never made an electric start 250x. 250x's where made in 87,88, 91 and 92. then in 1993 thru present they made the 300ex which is electric start. the 300ex is 99% the same as the 250x, it only has a little more power, electric start, and heavier spring rates. they also never made either one with both starting systems.

[wwclea01]

Ok I may be wrong. I was about seven when my dad had a 1992. I am 90 percent sure that it had electric and kick sart. I remember riding it and killing it alot. I know that when I was seven I couldnt have kick started the thing.

[stonerider250x]

i think im gonna get a profab 295 kit for mine but i dont think it will come soon:(

[YZEATER]

you are wrong, they never came standard with electric start, not until 1993 when the made the 300ex. it mat have had a goki starter kit fabbed to it but that is the only way.

[bradley300]

i have the only 350 big bore i have ever heard of. it is a 300ex, but it should work just as well in a 250x. but, it will not be a true 350 unless you stroke your crank, b/c the 300's have a longer stroke.

gthunder custom built it for my quad. it is a true 350cc 11:1 compression (pump gas works fine), full race port, wb high rev cam and a 400ex carb.

this motor got me the holeshot of my life at the TX gncc, left the entire class in the dust with the exception of a worked blaster and dave macarols 300ex (342 stroker)

this thing FLIES, i mean scary fast with stock gearing, wheelies 4th gear even with my LSR +1 swinger.

definatly give laz a call or check out www.gthunder.com. just ask him about the motor he built for me, he should know what your talking about. you will love this motor.

[ghak99]

I have a stroker crank on the way, Are you happy with the 11:1 and do you think 12:1 would be too much?

Thanks
I will give them a call.

[bradley300]

the 11:1 runs awesome, 12:1 wouldnt be too much, i just didnt want to buy race gas

[ZSK]

Which would be a better trail/woods motor the 313 or 330 for the 300ex?

i like big jugs
im talking about the motor parts
perverts

[ZSK]

Originally posted by WayFastWhitey
i like big jugs
im talking about the motor parts
perverts

What are you talking about?:huh

[ghak99]

Can anyone tell me what a stock rod for a 250x has on it for identification marks?

[AtvMxRider]

Originally posted by WayFastWhitey
i like big jugs
im talking about the motor parts
perverts http://pictureposter.allbrand.nu/pictures/atvmxrider/whocares.JPG

[hondapunk]

350 eh almost makes me want to redo my 330 :blah: I only did the bore kit no cam or anthing and its the same as a 400 but has more pep. i can just dream of what kind of balls that 350 has

[BLURR250X]

I have the pro fab 350 kit in my 250X. 12:1 compression and needs race gas.No complaints so far.It was expensive to do but i would deffinatly recommend it if you wanna put that kinda cash into your quad.