The KX is good at 32:1 and the RM will run cleaner/crisper with a 32:1 ratio also. I experienced this exact same problem after I dailed in my CR125s jetting to where I had a tan plug at every throttle position and crisp response with no bogs or surges, I had a tiny bit of spooge leak from the silencer and exhaust manifold and experimented with different oils to try and lower the spooge. My results were....
1st. Yamalube 2R - spooged alot and throttle response wasn't crisp enough, and was smoking alittle
2nd. Klotz BeNOL - throttle response suffered in the bottomend, bike smoked some if I was at low RPMS, burned dirty if I didn't keep the RPMs up, and spooged alittle more then the Yamalube if I did slow trail riding
3rd. Bel-Ray H1R - Response was crisp but still had minor spooge and almost no smoke
4th. Maxima SuperM - Response was crisp and had almost no spooge but a light mist which wasn't nothing compared to what the other oils did and almost had zero smoke but only at warm up it smoked. I found SuperM was the best oil to run in my bike and was almost the cheapiest