Re: have REAL power loss now!
sounds a little low but I think more important would be how does the engine sound and what are the roads like.
That black plug.the sign of rich running, could well be from the first carb... Still wait for the real mechanics to jump in. I would still check for an air leak around the manifold joint. It is simple to do and can't hurt. I have an o ring in the bottom of my joint and never had any more trouble from it.
Also how does it run with the choke on. That might be interesting to know. Mine bogs down after a few yards with the choke on to any degree. That's how it should act.
My posts have entertainment value only. A bike ain't yours till it has your blood on it. Then it owns you.