I hate to say most problems are the last thing worked on, but it's often the case. Me included. When you did the clutch, did you opt out for new clutch springs? Did you at least keep them all in the same place and same order? Clutch springs often get weak and need new ones, or get scrambled and get cranky. Sounds a little like clutch chatter, which in my book gets blamed on the springs, providing everything else is ok. It only takes one weak spring to mess things up. Double check those part numbers also, to make sure it was the right friction plates. Sometimes there are small differences betweens years of one model. I don't know your bike that well, but it's that way with some Hondas. The smoke coming out is probably normal, it's cooking down in there, after all. Check some other bikes and see what they are doing. Since the engine is running, the back sides of the pistons are pumping air back and forth. As well as the gear clusters. Oil leak, yes, clean or replace gasket. If that's where a shaft turns, check the oil seal on that shaft, it might be leaking. A little is ok, a lot is not.