250ES - best performance upgrades?

[TheRealFatShady]

I have a stock, beat up 250es. Needs tons, like plastics tank seat covered, cleaned up, battery, and I believe has low compression.

I was thinking of this:

400ex or 350x carb
Big bore kit - where can I find one? (Or maybe TRX 300 top end????, or high comp. piston kit)
Barnett clutch - don't want stock auto clutch slipping
Upgraded cam, not sure which to use
27-30" tires
Lift front and rear of bike, like the camo ones on here
Aftermarket exhaust - found supertrapp muffler from a 250sx, think it will fit nicely?

Is there anything else I can/should do? Basically I am going to put a lot of money and time into it to make it a GIANT monster. I have other 200s/similar models to use for regular stuff, so this is going to be my crazy, humongous mudder.

And is there any truth to rear ends going out/stripping out? I've heard this has happened to the TRx300'S with big rear tires? Not sure if there's any truth to it.

thanks and wish me luck

[mooseknuckle]

Make sure you keep clean oil in ths rearend. Mud and water will destroy these shafty rears fast!

Haha...i just realized how old this thread is.

[Hurricane635]

I'm currently testing a 360cc big bore stroker kit on a sx, using a trx350 crank and a special piston. How long do have till you would want one done? The 300 top end won't work, due to a larger pin, besides it's the same bore. Webcam makes great cams for these motors.

[mooseknuckle]

Haha...sorry Huricane, I bumbed this 3 yr old thread, But I'd like to hear more about your test results!

[ps2fixer]

Even though this is "kind of" old, if the OP wants to make a mudder and is worried about the rear end, rebuild it, new bearings and seals. Check the oil regularly and it should do well. Of my understanding, the TRX300 rear ends are not sealed the same way, and mud/water gets in easy. I saw a post a while back of someone putting a 250es rear end in a TRX300, welding etc, but it ended up being an upgrade for them.

I think it would be neat if we could find a top end that would interchange to make it a 400-500cc :D. Of course by then, could just put a different engine in from a newer shaft drive quad / shaft drive motor cycle.