Multi-cylinder bikes

After searching through motorcycle history to find first I wanted to do a feature on production motorcycles with more than 4 cylinders.

The earliest six cylinder bikes that I'm aware of are Honda's grand prix bikes. Honda raced the in the 250cc class with their RC machines from 1964 to 1967.

The first production six cylinder motorcycle came from the Italian manufacturer Benelli. Benelli offered the the 750 and 900 Sei, "Sei" being Italian for six.
Honda later introduced, what has to be the most known inline six motorcycle, the CBX. The CBX was insipered by Honda's six cylinder race bikes, and the bike was a techinical marvel in its time. Dispite being Honda's flagship the CBX didn't sell well, and lasted only a few years.
Kawasaki also offered a straight six bike called the KZ1300. The 1300 was watercooled and weighed significantly more than most four cylinder bikes, and thus did not last very lone. Kawasaki's Goldwing competitor, the Voyager, was initally based off the KZ1300, but was later offered as a lighter four cylinder model.
Of course Honda revisited the six cylinder design when they added two additional cylinders to the four cylinder Goldwing. The result was a 1500cc watercooled flat six, that helped the Goldwing dominated the fully dressed touring market. The Goldwings displacement was later bumped to 1800cc's which is offered today. Honda also created the "standard" Goldwing cruiser model, the Valkyrie and the limited factory custom, the Rune.

The only production eight cylinder motorcycle that I'm aware of is the Boss Hoss. The Tennessee based company has been puting small block Chevy V8s into motorcycle frames since 1990.

Here's some V8 models that are more "prototypes" rather than production machines.

Curtiss V8

Honest Charlie Flathead Ford Motorcycle

Drysdale V8
Morbidelli V8