Spooge Problem

Don't know about Maxima oil one way or the other. I run Mobil 1 MX2T @40:1 with good results. A tad less spooging and smoking than Bel Ray H1R at same jetting and ratio. You didn't mention altitude (or airscrew posn - typically 1.5 as a starting point) , but your jetting would look reasonable if you were around here (800-1000 ft). While we know that jetting usually lies at the root of spooging problems, there are a couple of mitigating things (i.e. bandaids ;) )you can do that may help. Switch to a BR7ES plug. Unless you are screaming around in top gear all day, the KDX will benefit from the hotter plug. Install a set of Boyesen power reeds.

You may have to go leaner on the jetting. There are KDX's out there running leaner than yours, but I hesitate to say "do that" since you really need to do some plug readings to see where your bike is. Also the stock needle is not necessarily the best choice. There's been a lot of work by KDX forum members (acutemp, canyncarvr, fishhead, and others) testing alternative needles and jetting combos and some have had good luck with the Keihin CEL needle (3rd or 4th clip) for a bike with the stock slide.