I do most of my riding on the roads and the bike was just running out of puff and feeling stressed. It was fine for running up some of the steeper naughty bits I shouldn't have been riding on, but on the road the engine simply hasn't the grunt to pull it off.
FWIW I fitted a -1T on my Caponord when I had it, and although that moved the revs up by 250rpm for 80mph in top, the bike didn't feel stressed at all.
I like to try things if I can, and sometimes it doesn't work out.