From my dyno tuning data on the CVK in my 2012 KLX250S , I assumed my KLX300 would need the same or larger DJ main jet. My KLX250S is currently running a DJ150 main jet and waiting for Dyno time to test - but it is running like a raped ape.. The only jet I had available for the KLX300 was a DJ146.. On the KLX250, that jet would get a top end AFR of about 12.7:1 .

Also, the KLX250 needed a #40 pilot - so one went in the KLX300 as well..

I am near sea level (500-900 ft ASL) in North Texas,,, DJ2206 installed as per instructions for stage 2 (but now with the DJ146 main jet), stock exhaust with end cap removed, lidless(of course)...

I have not fine tuned the fuel screw. I set it at 1 turn out. It fired on first kick.. I will set the screw midway between idle drops later today..

The bike now pulls engine only wheelies, quite easily, in 2nd gear and carbs perfectly - Probably a 3 hp increase over the standard stage 2..

 

After setting fuel screw to midway between idle drops, went for 2nd ride.. Outstanding performance.. Unassisted, power only, wheelies in 1st and 2nd - power wheelies in 3rd with a little tug on the bars..