Hi folks! I just bought an 09 KLX250S at 2k miles and it came with a two brother racing muffler (a bit loud for my taste), plus I got the original muffler from the seller. The seller told me that if I put the original muffler back on that I would have to rejet the carb (to original?). Is this really necessary? I am not sure what rejetting the seller has done for the two brother muffler. Would putting the original muffler cause any problem without rejetting? I have never rejetted a bike before so not sure what the implications would be. Also, does the two brother muffler add enough power to put up with the noise? Thanks

 

The OEM slip-on is pretty restrictive so you'll see a small decline in power. What about selling the 2 Bros and buy a quieter FMF Q4. I doubt you'd have to rejet and you still keep the same power. The Q4 is louder than stock, but not nearly as loud as the 2 Bros.

 

Can the seller tell you what jetting he did do to the bike? Was a DJ kit installed or just "stacking" the stock needle and changing the main jet? You'll need to know this before making changes...or just tear into the carb to see if it's a stock needle or DJ stuff.

 

Unfortunately, I lost contact with the seller and can not reach him, and he didnt tell me what he did. Is it easy to idenify the types of jets and the needle? Do they have some sort of numbering on them? If so, I can open it up and look. I did a test run with the original muffler and it seems to run fine; no extra heating or rough running. I like how much quiter it is even though I took the snorkel out too. Maybe a little loss of power (or I just feel that way due to the quiter running bike).

 

If your worried about noise goto the 3brothers web site and order the quiet insert. The out let is about the size of a quarter and tames the noise level down quite abit especially at idle.

 

If you pull the carb, forum members will be able to help you identify jets and needle. Post up pics and a description. Stock needle is not adjustable (no clip). Jets are numbered, but numbering is not comparable between manufactures.

 

Thanks, this sounds like a good option. I found the sound suppresser tip for my model P1x (-7 to 8 db). This way, I will keep the extra power from the muffler as well as the jet kit with less noise.

 

If the jetting was changed for the pipe it was made richer, going back to the stock piece would cause a rich situation not a heat issue at all. By pulling the snorkel you may have improved the jetting if changes had been made for the performance pipe. Small changes on the airbox side make more difference than on the exhaust side. Most of us when we were kids pulled the muffler off our mini bikes and they still ran fairly well but as soon as you opened up the breather it was obivious something was wrong.