I think you'll find working the range above 4000 will definitely be the sweet spot for crisp performance either way.

When it comes to the DynoJet stuff KLXter is the go to guy. He has them down as pat as anyone does, from what I've read he's probably better with them than DynoJet when it comes to the KLX250.

 

Well finally the weather was a few degrees above freezing and I got to take the bike out for a quick rip around town. The new jetting/slide spring made a surprisingly big difference, the throttle is noticeably more responsive and the bike doesn't feel totally gutless below 4000 rpm anymore. Feeling a lot better about buying this bike now! I installed some ebay bark busters and bent up a simple fender delete from some 18ga steel. Thanks for the responses, I'll get some updated pics of the bike once the weather is nice enough to actually ride somewhere interesting.

 

Don't loose the stock slide spring!

It is mandatory for if/when you or a future owner wants to go for a max performance lidless setup..

With the stock exhaust, you should only run sans snorkel with lid on and install the 2152 kit as per instructions.

The 2206 kit has the DNO352 needle in it - superior fuel control over the DNO228 in the 2152 kit when used properly in a max performance setup. It is LEANER in the low - mid rpm range but with a rich top end. Exactly what the KLX250S requires when tuned for max power.

Your DNO228 needle will work perfectly fine though - as proven on the dyno..

 

Well my thread has been pretty quiet, for all the right reasons, riding lots and enjoying this bike!

Took it out to some trails last weekend and had a blast! Coming from riding mx bikes I was actually really impressed how light and agile this bike felt in the woods. I ran out of suspension once when I got way out of shape on a heavily whooped section (not the bikes fault hahah) and other than that I had no complaints of how the bike handled or the available power. Can't wait to put a bunch of kms on this bike this summer!