Excess fuel is easy to confuse with oil smoke smell, but I can't really describe it. I will say that I was confused by it on my bike for a while, but with new pistons, rings and bores along with a rebuilt cylinder head with new valves and guides, I have realized that "oil smoke" smell was really excess fuel. Did you pull your idle screws out to make sure the correct parts are in there? I've seen random washers, o-rings, plastic thread and different springs show up in those assemblies which makes it hard to dial in the mixture just by setting each screw to the same number of turns. Also, did you blow the air circuits clean when you rebuilt your carbs? The air circuits can get clogged up easily.
One thing about starting super easy is that your bike really shouldn't. It should need a little choke until it warms up. Starting easily when cold is indicative of a rich mixture. Since the bike starts up on the idle circuit, that points to the mixture screws and/or the idle jet setup being too rich. FYI, the idle jets heavily affect idle on these engines. Even your main jet is going to have a noticeable affect even at low amounts of throttle. I've seen a few different graphs showing where the various carb circuits influence the mixture and I don't think most of those graphs are correct for the 350f and 400f carbs. The 350f and 400f carbs are noticeably affected by each fuel circuit at all throttle positions, although each circuit definitely dominates at specific amounts of throttle.
Have you checked your mechanical advance on the timing to make sure it isn't frozen or sticky?
I don't think you should consider replacing your rings just yet. If you honed the cylinder anywhere near to correctly, then those rings will seat in. At this point you should be looking at your various controls (i.e. fuel ratios, timing, etc.)
Camelman
PS, there's a chance that you might need to jet down on your idle circuit. Just putting a 4-1 on the bike doesn't automatically mean you have to jet up.
