If I buy a header from fourstrokeworks.biz for my stock exhaust will i there be an improvement? will it fit my stock can? If i decided to up grade later will it fit a "slip on" or would i have to buy the header specific to the company the can comes from example... fourstrokeworks.biz header with a pro-circut or fmf can? and does anyone have anything for sale??? i'd even take the klx 300 set up over what i have now, i just feel its totaly congested.

Oh and if i put the kdx intake (with jets and what not) would i HAVE to buy a diffrent exhaust right away or could i get away with just drilling the stock one with like a 12" x 1/2" bit ??

 

Will it fit the 250S muffler--no.

If you get a 300 muffler--yes.

Will you have a good system with a 300 muffler--yes.

Anything using a 250S muffler is garbage though. The 300 mufflers & 250S mufflers are very different in that the 300 is much more free flowing with a 1.5" outlet vs the 250S roughly 3/8" outlet. Modifing a 250S muffler does not equal a 300 muffler either as by then you have disabled your spark arrestor etc.

 

forget about replacing the header right now. wait until you can do the whole thing at once so that you don't run into fitment issues. if your drilling out your stock can your fine with running the kdx snorkle and jetting the bike. don't go nuts with the jets this time around though. you won't be getting that much more air with just drilling the can so you don't want to go huge on the main right now. once you get a full exhaust then you can go up to a 125 or 128.

 

Pie,

First of all, there's no such thing as a"quick exhaust question", especially on this forum.

It appears that you, like me, have decided that the stock exhaust has got to go. Very little gains can be made by drilling out the stock can. I can only recommend that you decide on your performance goals, and purchase the components to achieve that. If you change the exhaust, you will have to rejet and open up the airbox. If you change the jets, you will have to change the exhaust. It's best to wait until you have all of the pieces to get it right.

Good luck.

 

alright well then on that note, keep me posted if anyones got one for sale (self employed = pay mad loot to the gov this time of year)

I've got all the parts except the exhaust, guess i'll try and find a 300 exhaust for now (under 100 from what i hear) and then i'll up grade to the full muzzy or what not later on.

 

The stock 300 can usually be hard for around $50 shipped on e-bay, though they may be getting pricier due to more KLX250's being around.

It's not too shabby performance or sound wise...
click here
sorry dunno how to get it embedded in here, I've tried every button on here and every link photobucket offers

 

The fourstroke works header will fit the stock 250 muffler- I have one- some power increase but not as much as I would hope for- I ordered a muffers from them but its is on back order from December 2007.

 

How since the 300 & 250 mufflers are different diameters where it joins the header & different lengths as well. Did he modify it for you before he shipped it?

 

<----curious george over here wants to know as well...