what's the culprit?

So, some of you may have been following my troubles in the carburetor section, but as a short recap, my gas mileage was horrible and after a lot of troubleshooting I found that my petcock had failed. Got the bike running like a dream but I have a new issue.
One of my cylinders, number 2 to be exact, seems to running a lot cooler than the other three. I can still put my hand on the exhaust out of the head without burning my hand...the others burn me even at idle...
what could be the problem?
Also, after inspecting my spark plugs once I got the bike running well, I found that number one still looked black, suggesting running rich, but number four was white, suggesting running lean and hot...EH?

If the #2 plug is WET as well as black, the usual suspects will either be spark or a valve issue.

Easiest to deal with is spark - given that the #4 cylinder is firing, the likely problem is between the plug and the coil - fouled plug, bad plug cap connection, or bad wire. The coil itself could be shot, byt that's getting further down the list of possibilities.

It'd be worth doing a compression check on #2 - quickest way to tell in there's a valve/compression issue.