1974 Honda CR125M Elsinore 
Claimed power: 21.7hp @ 9,500rpm (claimed)
Top speed: 60mph
Engine: 123cc air-cooled 2-stroke single, 56mm x 50mm bore and stroke, 7.6:1 compression ratio
Weight (dry): 179lb (81.4kg)
Fuel capacity: 1.6gal (6ltr)
Price then/now: $740/$2,000-$4,000

In 1973, motocross was hot. Motorcycling as leisure was big business, and lots of kids lived within easy reach of places to go offroad riding, with lots of opportunity to explore almost in their own backyards.

With aspiring dirt riders pouring onto the trails, motocross and enduro organizers found little difficulty attracting competitors to their events. One of the most famous offroad races, immortalized in the movie On Any Sunday, was held every year through the Sixties and early Seventies in the Southern California desert town of Lake Elsinore, with part of the route going through the downtown streets. More than 1,500 riders regularly turned up.

But while it was easy to find a place to ride, it wasn’t so easy to find a really effective small-bore motocross bike in the 125cc range that would appeal to younger riders. Dirt Bike ticked off the choices in its September 1973 issue, starting with the Bultaco 125, which was screamingly fast, but frighteningly unreliable. “Learn to live with its mechanical suicide tendencies,” Dirt Bike editors said. “If it runs, nothing can keep up with it.” Dirt Bike’s editors were pretty much down on the category: They thought the Sachs- and Zundapp-engined specials on the market were heavy, had bad shocks and unreliable gearboxes; most of the Japanese 125cc bikes didn’t handle well; CZs were heavy; Husqvarnas couldn’t keep up with Bultacos and had unreliable gearboxes; and Hodakas were fun but didn’t win a lot of races. According to them, there wasn’t much to be excited about in the 125cc class — except for the newest offroader from Honda.

Honda makes a 2-stroke

Honda had built its brand and reputation on 4-stroke engines. But Honda wanted to be the pre-eminent motorcycle company in all types of motorcycling, and by the mid-Sixties, the only competitive offroad bikes were 2-strokes.

While management mused over this puzzle, Honda staff research engineer Soichiro Miyakoshi kept busy catching up on 2-stroke technology, obtaining bikes from rival makes and stripping them down. Hypothesizing that a good power-to-weight ratio was essential for motocross success, he headed a team that designed a feather-light 250cc 2-stroke prototype, which they sent out late in 1971 (with no name on the tank) to compete in Japanese motocross races.

By the spring of 1972 enough of the bugs had been worked out to allow the Honda name to grace the tank. Now known as the RC250M, development continued on motocross tracks around Japan, and a smaller 125cc version was tested in June of 1972; before adding gas, it weighed a mere 154 pounds.