honda cz 125

Why are the clutch and gear-box on the left-hand side of bikes?

You are correct, and it is also better to brake ‘across’ the body. The most ergonomic arrangement for a right handed rider is for a left foot rear brake, right foot gear shift with the gear lever going down for a higher gear and lifting up for a lower gear….. And that is what almost all British motorcycles ( Triumphs, BSA’s, Nortons, Matchlesses, AJS, Ariels, Excelsiors, Vincents, Brough Superiors, Greeves etc etc, used until the early ‘70’s, ( in other words the vast majority of ALL motorcycles). The Japanese however did not understand the ergonomic benefits but thought that keeping the gear shifting on one side and braking on the other, was more logical. As Japanese bikes came to dominate the markets, and as American riders, who rarely had ANY training started getting confused between the traditional British system and the Japanese system and crashing, in the early ‘70’s the US standardised the Japanese system so all bikes HAD to follow that system in order to be allowed to be sold in North America. The ‘down for up gear shifting pattern was so much better for many years racing motorcycles continued to use it and I certainly found the ‘old’ system more natural to use even though my first bike ( A CZ Enduro) was a left foot shift bike. Strangely though, my 2010 ‘go to work’ Honda 125 Cub uses a ‘down for up’ pattern possibly because it is derived from and a direct descendent of a 1958 Honda motorcycle ( the C100 Supercub….The bike immortalised in the song ‘Little Honda by the Hondells and later the Beach Boys) Although being semi-automatic does not have a hand clutch lever.