I must be doing something right. My 83 is getting 48-50mpg and I use the throttle pretty hard since i modified my exhaust. (sounds goood!) hard to keep it under 80mph.
Was getting 42-45
The only thing I did was remove the top airbox cover and strapped two hacksaw blades over stock air cleaner, and I cut the tips off the exhaust and removed the baffles, then modified them (so it was'nt too loud) then I welded the baffles back in.
Sound and runs like a V-Max. Kind of some redneck engineering but it sure runs great.
Tracy.