Hi I just got an 06 klx250s and was wondering what would be the best slip on to use with the factory header and what jetting I should use.

 

The DG slip on is the least expensive - $ 150.00 - and it's loud.
The FMF PowerCore 4 is about $ 300.00 - and it's loud.

I have both - I like LOUD !

Either one with the dynojet kit set up using stage 2 instructions and the airbox lid removed will make a huge difference.

The instructions for stage 2 left me still very lean at my altitude. I had to go #132 with the needle raised one extra slot to get the Dyno AFR chart to show good mixture.

 

Thanks and will both of them bolt up to the factory header or should I get a header. I just got the bike what all can I do to make more power. I don't wana do a big bore kit till it needs it. Also I'd like to find a fender elminator kit and flush mount turn signals but can't seem to find any for the 06

 

Also I can't seem to find the dyno jet kit for the 06 all I'm finding is for the 09 and up

 

Mikedj, You can look at my posts for Dyno test results using the DG-R with the stock header vs the full FMF system (with megabomb) The DG-R fits right in the header. The FMF slip-on will fit only after you remove the stock exhaust seal from the end of the stock header.
Remember that I have the MCM mod and that your '06 will not need the MCM - so our bikes are similar and you should expect the same results as I have.

 

The carbs are the same and the 09+ DJ kit will fit '06-'07. DJ should fix that. I've asked them a couple times to, but they're too busy I guess .

The KLX300 kit #2206 will also fit '06+.

I started with an HMF Performance slip on. It was loud. Now using an FMF Q4 with quiet core insert. The HMF may have given a little more power, or maybe it just felt like it due to the sonic reverberations in my head.

Reports on header hp improvements seem to go both ways with the differences generally limited to an hp or so. Save your money for a big bore.

 

Big bore all the way, look at the prices, no comparison for power gained.

Other than that, carb kit, slip on and air box lid are the way to go. Can tell you for sure though, I'll never go back from the pumped carb. (What a mess jetting though)

 

mikedj, I understand you not wanting to go with a BB kit until your bike needs to be torn down.. I feel the same way bout mine. Mod up your bike like I did - minus the MCM of course - and you'll have pretty close to the power of a BB on a stock bike and you'll be set up for big gains if/when you do go BB.

 

Thanks for all the advice guys. I think I'm going to go with the fmf mega bomb and power core 4. With dj jet kit. I just installed today a black ufo front fender for 2012 kx450f on my 06 250s bolted right up. And ufo black fork guards from 96 kx250 had to drill two holes and had to make I shim for the upper guides. I had some 1" 3m weather stripping laying around. It worked out great and I think it looks awesome. I'll post pics as soon as I figure out how to lol.