Is the pump working properly? Try disconnecting the fuel line from the carb and put the end into a container. Pull the rope a few times to see if any fuel comes out. You should get some every crank.
If you are getting fuel, the inlet needle/seat may be stuck shut, which doesn't allow any fuel into the float bowl. A good carb cleaning will solve that. The Keihin carbs have a few more parts than Mikunis but when I had Enticer 300's, I didn't have to buy kits to clean. Be careful not to tear any gaskets, especially the float bowl one.
I doubt mixing the oil has anything to do with your problem. JMHO