250es/sx Bigbore??

[atcmatt]

Gday,

I know this topic has been gone over before but i never really got a straight answer.

Does the old trx300es' jug bolt right upto the botom end of the es/sx motors? If so can the head be bolted right ontop of the trx300 jug? With this all being said and done would that make the cc's jump from 250cc to a healthy 300cc? Or would you have to swap out the crank aswell to make it a true 300?

Would the trx jug be higher than the es/sx one? Or is it just fatter with more piston space?

Would the crank fit right onto the crank shaft too? Im assuming the cam chain would need to be changed aswell to the trx300 one, am i right?

Has anyone got any leads on a bigbore kit that were made back in the day? Im guessing the "bigbore" would just be like bolting up a trx300 jug?

Do you think you would gain much power from this modification?

Thanks in advance

Matt

[Dads]

I hear the 300ex will bolt up and the piston shoulds fit the rod

the head for the 300 would have bigger valves, intake and exh may be bigger too

[whiteman350x]

J&M atv supply sells a direct bolt on 300cc kit that fits 250sx,250es, and trx250.

[Jason T]

We are just about to attempt this conversion on our SX, I will keep you updated on progress!!!

Jason T

[atcmatt]

Thanks for all your replies. Do you know how much tose kits are going for whiteman?

Matt

[BigGreenMachine]

doesnt the trx 300 2wd motor just bolt in, not sure if the mounts would need modification. just read that it fits over on .org

[eh_tee_see]

nononononono!!! First things first!!! You use the trx300 2wd or 4wd UTILITY quad jug and piston/rings. This modification brings it up to 282cc. You keep the 250sx head and valves and what not because of the more aggressive rocker arm design. I don't know if the 300 motor bolts in, i have checked and i am pretty sure it doesn't but i wouldn't do it if it did because i beleive the 250sx features a higher geared transmission. This mod will absolutely NOT make your bike go faster; it will give you more power to get to your top speed faster, and make you wheelie easier. It can make you go faster however, if you magically change the pinion size inside the differential, or if you plan to run the motor at 13,000 rpm's.

[BIG BAD RED]

does the sx head mount up to the trx cylender but thne onto a 250es.... :P

[atcmatt]

Im pretty sure the trx head will bolt right up form what ive heard. Will it make much of a diffrence with anm sx cam and that jug on it? Anyone got a good sx cam they will sell to me here in aus?

Thanks,

Matt