Against the odds

BSA’s 343cc B40 model, introduced in the early Sixties, isn’t the first choice of machine to build into a classic MXer; it’s too big for the 250 class and underpowered in the 500 class. Yes, Jeff Smith gave the 500cc riders a scare when he turned up with a factory-prepped B40 but most club riders weren’t of his calibre and none had a factory comp department behind them. The B40 did have the twin advantages of being a lot lighter than a 500 and hence a better power-to-weight ratio. A lighter bike means the available power has less to haul around and the smaller mass means it is less tiring for the rider. Such attributes were not lost on those outside the factory too.

Eric Cheney for instance had recognised these attributes very early on when building his own race bikes in the Fifties and carried on with the theme into the Sixties. In part the need to build such machines was because the main factories didn’t make a lot of competition