One of Herbie Durkin's Globe of Death bikes from 1950 - a short-wheelbase Tilbrook - fabricated special frame - South Australia.
The machine has a Villiers engine, probably a 250 or 350cc. The very short wheelbase is to cope with the curvature of the dome/globe. The frame was especially fabricated out of heavy tubing to cope with the stresses of the globe. The axles are up to 3/4 inch diameter (19mm) to avoid shearing off due to the centrifugal forces generated. The dent in the rear wheel cover is due to a circus lion riding the bike and falling off. He landed on the bike and squashed it!
Thanks to Doug Gordon for the great story and the image.

Tilbrook Motorcycles & Sidecars