Difficult Normal Maintenance
I have had the same problem on a '98 VT 1100, and it can be damnably difficult to diagnose and fix. The overflow/surge tank is squashed up in the bottom of the frame lattice. The high and low level marks are impossible to see without pulling panels and using a flashlight and mirror. The reservoir stays coated in road grime, obscuring the level. The radiator fill cap is behind an easily removed plastic panel, but the filler neck and cap are in a hole. My fingers aren't strong enough to twist the cap off, so I use a pair of channel locks, taking care not to scratch paint from the tank, frame, cap, everything in the way. Only then can you see the real level of coolant in the engine, and you must do all this with the coolant below its boiling point or you'll get a face full of hot coolant. Way too difficult to do on the side of the road when the bike has overheated, which it will do in a big hurry with its small coolant inventory.
IMHO this is a common weak link in all water cooled motorcycle engines. Something as simple as a water pump seal leak (engine removal to fix), leaking hose, or faulty fan temp switch (my problem) will disable the bike, and you can't tell what's going on because you can't see the reservoir level. My bike had an intermittently faulty fan switch. The fan and temp light would come on in alternating, uncoordinated, and random order in relatively cool weather, boiling off engine coolant by blowing it out to the reservoir. Very hard to diagnose.