Nothing, other than basic maintenance.
New tires, chain, plugs, oil changes, brake pads, air filter (changed to UNI), etc.
This bike has an extremely consistent power band. The motor responds immediately to the throttle, whether on or off.
Very comfortable riding position with no wrist or back stress on long rides. Even as a 14 year old bike with 21000 miles on it, I wouldn't think twice about taking it across country.
Good fuel economy averaging just under 50 mpg. Can actually get close to 60 if babied, but that isn't much fun.
Inexpensive to insure and operate. These bikes also hold on to resale value remarkably well and run forever. It is not uncommon in warmer states to find these bikes with 50,000+ miles on them.
There were so many years that this model of the Nighthawk was produced, 1991-2003, that finding used parts is easy.
Everywhere I ride someone wants to buy it from me, so I guess others like it too.