There are a few different things going on here.
#1, that isn't how you calculate payload or tow ratings. Many trailers have a much lower % pin weight than most RV 5th wheels. Gooseneck trailers, horse trailers, car carriers etc have a much closer to 15% pin weight than the close to 20% RV's put on the truck. On a 14,400lb trailer that is 2160lbs vs 2880lbs, so while it may be possible for your truck to tow 14,400lbs it would have to be with the right setup. (Bumper pulls put even less weight on the truck)
#2, a full tank of gas is included in those payload numbers so that doesn't need to enter your calculation
#3, 2901lbs is actually very good for a 3/4 ton so that is on your side (my diesel High Country is only 2200lbs)
#4, you mention a motorcycle so I'm guessing this is a toyhauler. That may actually play in your favor for the payload aspect. The pin weight you mentioned is pretty high for the trailer weight (22%), which is common for toyhaulers becuase most of the cargo is loaded behind the trailer axles therefore actually taking weight off the pin. They make toyhauler unloaded pin weight higher than normal so that when it is loaded it still is in the 18-20% GVWR of the trailer range.
Lets take 2900-2300 (pin weight)- 200 (you)- 100 (hitch)
That leaves you 300lbs of payload left to play with for luggage, tools etc.
If it isn't a toyhauler and you are putting that motorcycle in your bed then you are well over payload.