Is it possible to add HP to my bike without changing exhaust ? Jetting ? Airbox? Carb ? Thanks

 

Big bore kit

 

Jetting is good.

Air box:

• can remove lid -but noisy under your butt,
• pull the snorkel
• put in the better flowing KDX200 snorkel

I'd recommend one of the latter two.

Bolt on one of the 36mm slide carburetors.

Put a KLX300 exhaust system on it. Not much louder than stock and far from offensive.

 

Keep in mind that the engine is basically an air pump. You cannot put in a higher volume of air without ensuring that the engine can exhaust that volume of air.

 

Without changing exhaust, eh..... Here is what I'd do - Get a DJ kit, Do the MCM, Find the best combo of lid/snorkel on or off and DJ needle/jet selections. I'd start with Stage 1 install and lid/snorkel on. The MCM will give you a whole new bike even with stock exhaust and intake/carb setup - I know, I did the MCM and ran it stock a few days having fun with it..

 

The stock pipe is the biggest bottle neck I would at least consider the 300 pipe, buy the jet kit as with it that close to stock you would have the jets you should need if you went big bore. The big bore will give you wheelie popping torque. With those changes the bike would look and sound nearly stock but would do things the stock one never could.

 

Thanks all for the input. The reason I want to do some mods is when I did mods to my dr 650 it seemed to run cooler and start easier plus added power. Although I liked the sound of the FMF Q4 it was quite a bit louder. So I would really like this klx to be more stealthy .
Klxster what do you mean by an MCM Thanks

 

Oh and is there a certain year for the 300 klx pipe to fit my 2006 250 and what do I need exactly to make it fit. Thanks Much

 

The MCM is the Marcelino Cam Mod. Find it in our stickies. I recently re-read much of the thread looking for any reason why it would not apply to pre-'09 KLX's. There is only one post suggesting that it would not apply but without any reasons offered. And, I could find no indication that the mod is less effective on older KLX's.

 

Pretty sure any 300 pipe will fit...but what you really need is the whole exhaust - header and muffler. I bought new header and pipe connection gaskets so I could mount it up straight away, as the one it came with was unusable.

On a side note, the 300 header is not any bigger than the 250, but has a larger outlet. If I could, I'd find a 300 aftermarket header designed to fit the 300 muffler, that way you would benefit from a larger diameter header too.

My bike sounded like a sewing machine, now it sounds like a proper thumper, but not loud.

And get at your fuel screw, if it hasn't been done yet. It won't get any HP, it'll just let your bike run on a proper amount of fuel, which will cool the motor as, it won't be so lean.