Wartime Oddballs: Indian 841 and Harley-Davidson XA

Not many people are familiar with the Indian 841, or Harley-Davidson XA. See one in the flesh and you'd most likely mistake it for an older Moto-Guzzi or a BMW.

Both are unique in the profile of their respective manufacturers in that they use a shaft drive coupled with a transverse twin cylinder engine layout, and both were inspired by the well-known BMW and Zündapp military sidecar bikes used in great numbers by Nazi Germany and its allies.

While both the XA and the 841 were promising at prototype stage, neither bike saw large production numbers due to the introduction of the Willis Jeep which turned out to be a much better battlefield vehicle than any sidecar motorcycle.

BMW invents the Shaft Drive Dual-Sport

When BMW launched the R80 G/S (the G/S stood for "Gelände/Straße", that is "Dirt/Street") in 1980, it elicited a lot of head-shaking in the motorcycle community.

After all, it was by far the largest capacity and heaviest offroader available; and it came with such street touring bike features like boxer twin engine, and Monolever single swingarm with integrated kardan driveshaft. However, the original G/S managed to single-handedly pave the way for an entirely new market segment of "Reiseenduros" (big touring dirtbikes).

Introduction to Shaft Driven Motorcycles

Drive shafts have been used on motorcycles almost as long as there have been motorcycles. As an alternative to chain and beltdrives, drive shafts offer relatively maintenance-free operation and long life. A disadvantage of shaft drive on a motorcycle is thatgearing or a Hobson's joint or similar is needed to turn the power 90° from the shaft to the rear wheel, losing some power in the process. On the other hand, it is easier to protect the shaft linkages and drive gears from dust, sand and mud.

The best known motorcycle manufacturer to use shaft drive for a long time is BMW. Among contemporary manufacturers, Moto Guzzi is also well-known for its shaft drive motorcycles. The British company, Triumph and all four Japanese brands, Honda, Suzuki, Kawasaki and Yamaha, have produced shaft drive motorcycles. All geared models of the Vespa scooter produced to date have been shaft-driven. The automatic models, however, use a belt.