Make 300ex real a 300cc ?

[fmftrx300ex]

I have an 01 300ex and i plan on doing a piston cam and carb in the next year or so...I want this thing to move!!!! And i am wondering if boring it up to 297cc's is worth it? Will i notice it? and will i be able to get a higher bore piston when tht one wears out or will i have to resleve?

[bwamos]

My thought would be to save that money and use it toward a port/polish/valve job and throw in a stock bore 11:1 piston. ;) You'll get a lot more bang for the buck.

[fmftrx300ex]

i am not doing stock bore and ports are so expensive!!!!!

[fmftrx300ex]

does anyone think the extra 25 or so ccs will be worth it?

[TRXRacer1]

Originally posted by fmftrx300ex
does anyone think the extra 25 or so ccs will be worth it? No, just go a little bigger. Do a 75mm and make it a 290. You'll have a hard time telling the difference between a 290 and a 300.

[bwamos]

Originally posted by fmftrx300ex
i am not doing stock bore and ports are so expensive!!!!!

Ok.. but a mild port really isn't that expensive.

You are not going to see much of an increase in power from 15cc's. Maybe 1hp, tops.

What you are going to see an increase from is the added compression of going to an 11:1 piston.

A mild port job even w/ staying with the stock valves will give you a significant performance increase. The stock head is very restrictive.

[fmftrx300ex]

Ok so how much is resonable and any one know good relibale places to get it done? i had some guy on here offer me a port for 200 but you never know...

15cc wont be much a difference but and a high compression piston and a cam should deffinately be noticable but it would be better to go with a bigger bore something like a 310cc and still do the piston and cam.

[TRXRacer1]

Originally posted by FoxHondaRider
15cc wont be much a difference but and a high compression piston and a cam should deffinately be noticable but it would be better to go with a bigger bore something like a 310cc and still do the piston and cam. If you're going big bore forget the 310 and go 330. It costs the same and is the same amount of work.

[bwamos]

The 310 & 330 both require (or should) a new sleeve. I beleive he want's to avoid that.

That's why I was reccomending stock bore w/ 11:1 compression. Just hone and insert new piston. Get a decent power gain from the compresion. Then you can use the extra cash for a cam & port.

A mild port shouldn't cost more than a couple hundered. It's a very simple process. It's when you get into more fine tuned porting w/ flowbench work and oversized valves that it starts getting a bit more expensive. ;) But a straight forward 300ex mild port job should be fairly cheap. The ports are designed for a smaller displacement. (aka the motorcycle the motor was inherited from).

You can just simply start off with the 11:1 piston w/ a hone and ring gapping, and see if that's enough for you're likes. Then if you wish you can always send in the head for a port later. ;)