Sir: follow Aaron's instructions above which are a great starting point. if you don't have a service manual, simply click the link below and download the correct one for your 2004 firebolt. these transmissions are very similar in style, content, maintenance and feel to most all sportster and XR1200 transmissions/primary assemblies.
if you perform the following in conjunction with what Aaron mentioned, the trans and clutch should both work very nicely. will NEVER be jap-bike-like smooth...but will work well once you learn the proper shifting procedure.
as follows:
lube clutch lever/perch assembly
lube clutch cable
adjust clutch cable and clutch pack properly and as one complete operation
adjust primary drive chain at room temperature. one-half inch of slack will be fine as per SM
drain primary fluid and replace O-ring on drain plug. it is the same O-ring and same plug as the swingarm/engine oil drain plug
drain the primary fluid. a full drain takes approx. 1 hour with bike in near-vertical position
refill primary with a top-quality 20W50 motorcycle specific oil RATED JASO-MA or higher ONLY! this rating means the oil is compatible with wet clutches, which your XB has. do NOT use REDLINE in the primary as it has a history of causing stator problems. MOBIL-1 motorcycle specific or AMSOIL primary/trans specific oils both work very well in these primaries.
lastly: after performing all of the above and you still find neutral difficult to locate....bulky erratic shifting....clutch dragging and not yielding full disengagment....clutch only starts to engage near end of lever throw....then the clutch will need replaced as you have burned/warped metal clutch pack drive plates along with diaphragm spring at the end of its life.
ENERGY ONE COMPANY makes a very nice replacement complete clutch kit. XL AND XR NOT the same.
CAUTION: DO NOT OVER-TIGHTEN EITHER PLUG OR YOU'LL EASILY STRIP OUT THE ALUMINUM THREADS THAT AFFIX THE PLUG TO THE ASSEMBLY!
https://www.buellmods.com/