ESO was a Czech motorcycle manufacturer that is not well known because they ran from 1949 to 1964 and they only built racers. The company was founded by Jaroslav Simandl, a former motorcycle racer who started with JAP engines and then had his company start building their own in 1950.
ESO engines started as a clone of a JAP unit and was originally designed for speedway racing. But they eventually created MX engines in 250cc, 350cc, and 500cc, all of which were paired with a four speed tranny with straight cut gears. Impressively, when you bought one of these from the factory, it came with a spare engine, clutch, and other parts! According to Motocross Action Magazine, ESO built great engines that ended up in heavy bikes, so World Championships were won by racers who stuffed ESO engines in other frames – like this Rickman unit. The MXA article also says that the Czech government thought ESO was doing too well against CZ, so they shut it down and had it absorbed by Jawa.
This example uses the 500cc engine and it was recently put into a new Rickman frame. The recent build was also given New Old Stock Ceriani forks, Betor shocks, Atlas clutch, Sun rims, Amal levers, and a AMC gearbox. It weighs 270 pounds, has run 2 events, and is ready to kick some ass in AHRMA. Race it and win, then show it and have people wonder what the engine is!
Find this Rickman ESO for sale in Dahlonega, Georgia with bidding up to $7,599 and the reserve not yet met