as I stated before I was attacked and insulted, NONONONONONO!!!
there is no benefit going to the stock 300 header in a performance sense. it offers nothing the stock 250 header doesn't. EXCEPTEXCEPT for a wider variety of slip-ons available to you now. slip-ons for the 300 will not fit unless you have the 300 header and vice-versa for the 250S slip-ons, but really the only one worth installing is the 2-bros for the 250S header.
but since you've got it coming, you may as well wait it out and enjoy the Muzzy once your header arrives. you'll learn to listen to what I'm saying, I speak the truth from my own experience or other experienced KLX owners.

 

It doesn't appear that captaintrps edited his post where he's referring to the fourstrokeworks.biz header which is the FSW header, otherwise there would be an edit record for it and there is none. I think this is just a case of a miscommunication. Again, please move along, piling on won't solve anything.

 

I stand corrected. I apologize captain, I misread your post. Still though, your remarks are out of line. If this guy is waiting on the FSW 300 header, you will see performance gains over the stock 300 header. If you're just waiting on the stock 300 header, well, the only benefit it will serve is letting you use the Muzzy slip-on. Again, I apologize for misreading. I still don't ramble imo. I know what I'm talking about as I've had experience with two KLX250's and two different exhaust systems going on both. I'm one of the few that have been around since early 2006; I've read every thread on this forum.

 

I just got my klx300 header in for only $88.00. A little different compaired to the klx250 header. Here are some pics so you can the difference. The klx300 is the longer one with bigger end pice and the same inlet diameter.

 

Where do you guys find these for such a low price? I look on eBay but haven't seen a stock 300 header or muffler in months.

 

Hobbs can you measure the exhaust port inside diameter? I forgot to do so when I had the chance.


I read about the header/port mismatch on the Stroker website: quoting Larry Rosseler >

"Larry tells us the stock head pipe is actually the same unit as used on Kawasaki's KLX 250. It has abrupt internal welds and its inlet face does not mate well with the exhaust port."
http://www.motorcycle.com/products/s...mods-3510.html


The stock head pipe flange has a black carbon ring on the mating surface. I modified my stock head pipe flange to match the diameter of the exhaust port. Then I rewelded the flange to regain any strength that may have been lost from the chamfering the inside obstructions.

After doing so I rejetted the pilot to a 38 as the a/f mixture screw was way out w/ stock 35 pilot jet. With all the mods done I am now working w/ a 40 pilot jet (still fine tuning as it may not work out- possibly one size to big).

 

So does your 09 have lots of snap now?

 

I posted this very one a couple of weeks ago. LOL

 

+ 1 on the grinding. Did my 'STOCK' (in AUS) KLX300 header when I fitted my Two Brothers M7 pipe. 5 minutes of grinding removes most of the weld. A little polish. Hey presto!

 

I am not sure about thumpers but I know that with two strokes is it all about the first curve. The less turbulence the better the flow through.