Will a Bigger motor fit in an SX?

[Tri-ZNate]

I have some time on my hands this winter and was thinking that since i have so many SXs I would trick one out. My first plan is to put a bigger motor in it if possible. I was thinking like a rancher, forman or even a diff make like a 350 big bear. Has this been tried by anyone?

[bigredhead]

If you're gonna do up an SX.. make sure to work in Reverse and elec start !

Need to stay with the theme !

just more power !!

argh arghharrrgh.

[Tri-ZNate]

Hell Yeah! Tool man! Gonna Make my baby purrrrrr.

[Dirtcrasher]

I have some time on my hands this winter and was thinking that since i have so many SXs I would trick one out. My first plan is to put a bigger motor in it if possible. I was thinking like a rancher, forman or even a diff make like a 350 big bear. Has this been tried by anyone?

If you want to trick one out, figure out a rear suspension improvement. The last thing the stock SX needs is a bigger, faster, heavier motor to try and ride without being tossed off. That rear pogo stick should be priority number one. I have been promising alot of guys that I would come up with something for the SX and I am still working on it. I'm not just gonna hack anything on there, I want it to look and work great.

[Tri-ZNate]

Well if the motor required a diff rear then I could try to make mounts so the shocks would work. The mounts im speaking of go at the top of the shock.

[03 ORANGE SHEE]

ever try the 86 trx 3504x4??, or a dirrect bolt in, an 88-99 trx 300 4x4?? same cases, different stroke

[Tri-ZNate]

Im making a list from what has been said in here and what I think. Any Adiitions? and remember I'd like to know what higher cc motor i can put in


So far.....
Things that need to be done to trick out my SX:

Different (refered to as diff) rear suspension
Smaller tires in back
New plastics all around (200x up front and 350x rear)
New motor
350x headlights
Twist throttle
New exhaust (probably cobra megaphone)
Bigger carburetor
K&N or UNI air filter


Any other suggestions?

[Tri-ZNate]

ever try the 86 trx 3504x4??, or a dirrect bolt in, an 88-99 trx 300 4x4?? same cases, different stroke

So far I havent tried anything yet. Also what makes the wheels up front turn in 4x4, isnt there another drive shaft that comes out of the motor for the front?

[hrc85250r]

[QUOTE=250sxwheeliepop]
Different (refered to as diff) rear suspension
QUOTE]

He means differential rear suspension, not different...

[Tri-ZNate]

I dont think I mean differential. If I have time im gonna try to make a different rear suspention


ADDITION: diff is the way I write different in short hand

[RichinMO]

Might as well get a 400ex jug and sleeve it out to 440, that should bolt up to your lower end. Hopefully you can get the 2 headpipes around the downtube. Do that and then upgrade the suspension front and back. Then worry about the piddly stuff-(headlights, stickers, etc.)

[Yamahammer490]

Well if the motor required a diff rear then I could try to make mounts so the shocks would work. The mounts im speaking of go at the top of the shock.

That picture looks like the quad has independent rear suspension. I've always wondered how a trike would work with IRS.

My guess is that it would either be real tippy and handle like crap OR it would give you a little leaning ability and handle more like a bike. Sorry to get too far off the track but the picture sparked my interest.

Aside from that, I like the SX with the wide front tire so please don't put a "X" front end on it.

[Wickedfinger]

Personally, for all the work it would require to get a TRX350 motor or even a TRX300 mill in there you really need to ask yourself if its worth it. I can guarantee the 250SX motor probably has more ponies stock than the 300 or maybe even the 350. Just because they have more cc's dosent mean they put out the kind of power a sport bike would need. Even though the SX motor is basically the 250ES utility motor, its tuned differently. My advice would be to work your motor - first thing I would do is look for an aftermarket exhaust, more aggressive cam and drop a medium compression or hi-comp Wiseco in it. You will see far better results.

[Tri-Z Pilot]

There use to be a 300 kit, I think four stroke tech made it (fst racing).
I'd put a 200x front end on, probably dont want to go too big on a carb, as you will loose bottom end the bigger you go, I hear cobra's are junk, might want to see if they made a supertrapp or DG system for it. Another upgrade is an 87 rear end. I hear they spice up the earlier models. Your going to want to watch how you mod the suspension, the shaft is to one side, and when you start playing around with independant units you'll have to measure pinion angles so you dont go binding your drivetrain.

[smokinp]

why not just leave the 250sx alone and buy like a 200x or 350x.sounds like you need one...