This was only one variation. The base was the motor and the two front wheels connected up to an after part of own construction. The motor was a one cylinder motor (fuel of unknown composition) and evaporator cooling. Eg, a water container around the cylinder and this hat to be topped up as the water boiled off. Cheers ulf
They are a very common sight inland in China &, as Ulf says, there are many variations. Many don't have cabs, there are LWB versions with 6 wheels, many have handlebar steering. Many look as though they are home made. Top speed seemed to be about 20 mph (unladen, downhill). Frequently seen overloaded & boiling over. They seem to be the workhorse of China.