that plug doesn't look right at all! The burning smell could be from everything working in after being rebuilt

 

I was always told the outer ring of the plug was colored from the low speed fueling and the center electrode color was affected by the high speed fueling.
with that in mind I think it looks like your rich on the low speed jetting and lean on the high speed fueling. How far did you ride the bike before you did the plug check? Did you run the bike wide open throttle, simultaneously pull the clutch in an kill the engine?
The color of the porcelain can be affected by the ethanol gas. Pretty sure the spots/deposits on the outer ring are from the additives in the fuel.
Someone with more knowledge and experience will be along with better analysis.

 

I rode it for about an hour in city traffic. I think the fastest I went was 70mph. I don't think I ever went wide open throttle nor killed the engine. The mechanic who had my bike told me he was running it for a bit with race fuel. I added 91 to it before my ride yesterday.

 

The race fuel will definitely give you an unusual plug reading. I would fill the tank with what ever gas you plan to normally run. You can probably use that same plug but most recommend start with a new plug. Find an empty / no traffic road, wind thr bike up thru the gears, try and hold wide open as long as possible. Simultaneously hit the kill switch and pull in the clutch at the same time. You don't want to pull the clutch in while the engine is wide open usually doesn't end well. With the engine off and clutch lever pulled in, safely coast to a stop on the shoulder or parking area. Let the bike cool off for awhile, then pull the plug and see what it looks like. If you can take a picture and show us. Or replace the plug with a used plug to get you home and send us a picture of the plug you did the high speed run with. Your looking for the outer ring and electrode to be a brownish color and the center porcelain to be a tan color. With leaded gas we tried for copper brown, but the ethanol/lead free messed that up.
One other thought, are you positive you don't have an air bubble in the cooling system? That could cause the bike to run hot.