Anyone want to guess what my bike's problem is? (x/post from the PNW Riders FB page)

Any excellent mechanics on here have a guess what's going on with my bike? Here's my little (longish) story. I have 2009 Kawasaki er6n. Almost 11k on it. Maybe about 2 weeks ago I start thinking that it's running not quite as smooth as it had in the past. I've got some scheduled maintainence due and it's subtle enough that it could actually be my imagination so I go about my business and keep in mind that very soon I'm going to need to do a little work on it. Then last week I start up my bike to head home from work, and it's now definitey idling rougher than it should. I get a block away and notice a bit of white smoke coming out of the exhaust. Ok, that's no good. On the way home it's getting rougher and rougher. Starts misfiring when I hit the throttle moderately hard. Usually around 5.5k-6.5k rpms. Ok, my bike is broken and I need to fix it. It felt at first like it was struggling to get air. So I clean the air filter and reinstall. Didn't fix it. Next I replace the spark plugs. The right side looked ever so slightly fouled. Wet oil looking stuff on the threads above the electrode. Nothing major but it didn't look right. Replace the plugs and boom! The thing runs like a champ. Took it for a short little test ride and it zips! Lifted the front wheel off the ground from a stop light without even trying. Awesome!

Then the next morning I load up to ride down to Bend OR for the holiday weekend. Start it up and it's back to running rough. White smoke and all. And a short spin around the block to see whats going on and the temp light comes on. I had to jump in the car and get on the road so that's the last news I have. Been out of town all weekend.

Anybody with more knowledge than me know what this sounds like it could be? I can do a fair amount of work myself but don't have the knowledge to diagnose the problem. Any ideas? Anyone around West Seattle enjoy working on bikes and spreading knowledge? I'd love to help do the work and would be willing to negotiate fair compensation as well. Long shot maybe but worth asking. I work exactly during most mechanic hours around here.

Thanks for reading if you made it this far. Any help is supremely appreciated!