You might be able to shorten it, by cutting the inner and outer down and fitting a new solder nipple, or even a screw nipple.
Another option is to re-route the cable, maybe around the left of the headstock.
Or you could source a shorter cable. My Kawasaki's throttle cable is identical to the T-bird one, except a lot shorter. It's a 91 ZR750
98 Thunderbird, 03 Speed Master