This is a motorbike a long way from home. It's built by Royal Enfield in India and is based on a British design from the 1930s. Here's the interesting bit - back in the 1950s, farmers who bought them began to do interesting things with the bikes. For example, they removed the original petrol engine and replaced it with one of the little stationary diesels used to drive water pumps, for a huge saving of fuel.
Eventually, Royal Enfield picked up on this and did their own version. That's the bike. The Enfield Taurus uses a
Full details are here (in German). One for the folk at Worldchanging, I reckon.
(Hat tip to Jörg Kantel.)
Unaccountable error of fact corrected.