This is from the site Bring a Trailer (https://bringatrailer.com/) ...
This 1990 Honda GB500 Tourist Trophy is a nicely preserved example of Honda’s tribute to the Isle of Man TT and has just 3,361 miles on the odometer. Imported to the US officially for just two years, these aircooled singles sold in limited numbers and predicted the rise of retro-styled bikes on the market today. This example remains factory-correct, has always been stored in a heated garage, and recently had its carburetor rebuilt. The bike comes with a clean Indiana title in the seller’s name.
These large bore singles were meant to resemble Manx Norton and other single cylinder race bikes from the 1960s. The engine is derived from the 600cc unit used in the XL600 dirt bike, and appears largely similar, though with polished cases and a street bike-appropriate exhaust. The side panels on the GB500 were metal, rather than plastic as often used on bikes of this period.
Honda dubbed the paintwork Black-Green, and from most angles appears black. Up close the green and metallic elements of the paint can be seen. Gold pinstriping and silver lettering show well, with no wear-through in the areas around the tank or the rider’s knees.
Seat vinyl appears to be in good condition, and while the rear clamshell on the seat is removable the area beneath is too heavily sloped for 2-up riding. The seller collects cars and bikes and previously sold his 1952 BMW R68 on BaT last year.
Instruments consist of a speedo and tach with a quintet of warning lights; four in the tach face and a side stand warning light below the speedometer. Metal, plastic and glass components all show well. 3,361 miles are shown on the 5-place odometer, and per the seller the bike has only been ridden about 25 miles in the eight years they’ve owned it.
The engine is a 498cc single with split exhaust ports and four valves, and was good for a claimed 33 horsepower and similar torque when new. The seller’s mechanic recently rebuilt the round-slide carburetor and states the bike rode well on his test ride.