I pulled the stock muffler off my bike and noticed a small sleeve in the slotted opening of the header pipe where the muffler and header join and are clamped together. It looks like a compressed aluminum material. My question is does this sleeve need to be removed before putting on a slip-on? The sleeve seems to reduce the header's diameter by about an 1/8" all the way around. My gut reaction was to rip it out of there but I thought I post before doing that. Of course, it's probably mute since I've got my eye on that full Muzzy setup now. Thanks for derailing me Travis! LOL!!!

 

It's the exhaust gasket. It seals the muffler and the header. You could use RVT silicone, but I don't think that would work very well because the head pipe is slotted.

 

Depends which slip on you fit. It comes out easy enough. I suspect you have the KLX 300R header, as we do here in AUS.(Where are you?) If so it gives you a larger selection of slip on pipes. You can choose any of the pipes for the 250S model if you leave the 'sleeve' in place. Remove the 'sleeve' and you will be able to fit any of the pipes designed for the KLX 300R.
I have the KLX300R header and have a Two Brothers M7 slip on. No issues with the pipe in 1500KM, except the confusion about the sleeve Kawasaki fitted into the header to allow fitting of the 250S slip on. Once that was dealt with i've had no issues at all. No leaks, vibrations, quality issues, and it's really transformed my ride.

 

Ok, it's starting to make more sense now. I'm in California. I picked up a 2-Bros slipon at my local Kawi dealer and it was for 2006 - 2008 KLX250S years - that's what the sticker on the box said. I pulled my pipe last night, it was late and so I wasn't paying attention and immediately noticed that the stock muffler was a lot narrower than the new 2-bros. I made a quick measurement and just assumed that the 2-bros. pipe was the wrong one. I took it back to the Kawi dealer this morning. After reading some more threads I decided to take a closer look at my header. Sure enough, I found the sleeve. If I pull that sleeve out the 2-bros pipe will fit. What's really interesting is that the stock 2009 header is narrow all the way up to where it connects to the muffler and at that point there is a weld joint where it goes to a larger size for about an inch, then the even larger slotted section is welded on. Long story short, I'm going to try out that 2-bros. pipe again. I think it will fit. Don't have the extra cash for a full system right now. Thanks for the info.

 

Does it look like this?

That's mine fitted to the Two Brothers. (07 AUS KLX250R)

This is a pro circuit fitted to an 09 AUS KLX250S.

 

Here's a tip. Don't remove the 'sleeve'. Just tap it in further with a socket or something, just enough to fit the slip on mid pipe. You shouldn't have to remove the sleeve, The Two Brothers pipe is tapered (large to small) to mate with both the 250S and 300R headers. Any problems PM me.

 

I looked at mine and it looks the same.

 

That is an obscenely clean machine old boy!

 

Both shots were from brand new bikes. She's got mud now.

 

Don't forget to remove the OE snorkel. Fit a #132 main jet and turn the fuel screw out to 2 turns from lightly seated (a good starting point.)