To All-
I am looking to put in a 330 bore kit in my '01 300EX. Other than re-jetting, what is required for this mod? Is is REQUIRED to put an aftermarket pipe on or to re-gear? Can I wait a bit on the pipe or do I need it before the boring? Thanks for the help.

 

No you dont need a pipe or anything else for that matter. BUT don't expect the same results that other guys with pipes/cams/carbs/air filters/rev boxes/etc have. You're not going to be blowing away any 400ex's with just a 330 kit. It's the combination of parts that makes the power, not just one part alone.
To answer your question, yes you can wait for those parts and you can do it little by little.

 

REQUIRED to make a 330

sleeve
piston kit

That will give you a 330cc motor

But for it to run like a true 330cc you need

Sleeve
Piston Kit
Porting, Polish
3 angle valve job
Cam
Valve Springs
CDI mod
Hard weld Rockers
Complete Exhuast System
Bigger Carb
Rejetting
Uni Filter(only because thats what i choose, K&N works some what...if they actually do filter)

So now your motor is up to par.

Now for your bike.

Better Shocks
Longer A-arms
Longer Axle

Then you will be out there with modded 400exs.