Have a couple things here, not sure if they're all related but I don't want to make separate posts. I've noticed some issues with performance when riding; occasionally after riding for 30+ minutes, the bike stalls out while idling at a light. Also, it hesitates when going back down to idle when the clutch is engaged. For example, if I'm riding at 4k RPM and come to a light, I'll pull in the clutch and downshift - holding the clutch the entire time.. but my idle speed doesn't go down to 1k RPM unless I let the clutch catch a little. My idle knob is set correctly, and as far as I can tell nothing is catching the throttle. It also only happens when the engine is hot. Here's a video (slow motion as well, really highlights the issue):
In the video I revved up to about 4k RPM and quickly let off the throttle. You'll notice it goes down to about 1.5k RPM for a second, then down to 1k RPM. This is after a cold start. If I let her warm up a bit (or go for a ride) the problem gets worse and worse as time goes on, to the point where revving up to 4k RPM it will go down to 2.5-3k RPM and sit there, never going down to 1k RPM unless clutch is released a bit to put a workload on the engine.
Second issue.. noticing my exhaust (painted with exhaust paint) is wearing on my cylinders in a very uneven way. The paint on the front cylinder is cracking and has lost it's gloss.. on the rear cylinder, the paint looks much better (closer to what it looked like when it was first applied). Now, of course I could have f'ed up somewhere when applying the paint, but I don't think that's the case.
Here are pictures of the front and rear cylinders: http://imgur.com/a/v5GbX
This leads me to think that the front cylinder is running hotter than the rear, which leads into the next "issue".
Third issue: Might be related to the exhaust. I installed new plugs two months ago, this is the first time I've pulled them: http://imgur.com/a/zCJ9x
The front plugs don't have as much build up compared to the rear. I also noticed the threads on some of the plugs have some deposits on them - not sure if that matters? They were all hand tightened and then tightened up an additional 1/4 turn with a socket wrench. Is one cylinder running rich/lean? Not sure how to tell.
Any advice would be appreciated!