I installed a Motoz Tractionator Desert HT on my KTM 690 Enduro about 500 miles ago. I'm very happy with it. It's the only dirt oriented DOT knobby that I've found that seems to last a while. I paid $117 shipped and I will buy another when this one wears out. I should get about 2,000 miles out of this Motoz rear.
I had good luck with the Dunlop 606 on my WR250R, but they don't make that in a 140 width, so I got the the Motoz instead for the 690. The Pirelli MT21 is also great except for the fact that my KTM wears them out quickly.
I know these tires might be a little more aggressive than you're looking for, but these work well for how and where I ride. Here's the Motoz on my bike with about 250 miles on it: