MBK 51

History of the MBK 51

The M51 is the moped Moped the most widespread. More powerful than the classic 50 thanks to its 10 p-intake AV enginear valves, it benefits from a more modern look that appeals to all moped riders.

Launched in 1978, this mythical universal moped, renamed MBK 51 after 1983, continues to travel the French roads despite the cessation of its production in 2002. A look back at an emblematic model including the many variations that have punctuated its 25 years of existence.

A sporty moped

1978: Motobécane launches the 51 range, derived from the M50.

1979: Motobécane launches the 51 Super, flagship model which will be available in many variants.

1981: Exit from the 51 West, which started a long line of choppers.

1983: Motobécane is acquired par Japanese Yamaha. Pedals are no longer required and can be removed from earlier models.

1987: Appearance of the first models with electronic ignition and kick start (Rock, Magnum, Daytona Cruiser) under the MBK brand.

1988: Renoimportant addition to the range with the release of Evasion/Passion, Swing and Sports.

1989: Arrival of the wave Racing with Rock Racing et Magnum Racing.

1991: Launch of the Hard Rock and series Club, entry-level models with reasonable equipment.

1996: The MBK logo replaces that of Motobécane, on the whole range. Exit from the Magnum Racing XR which met with great success.

1997: Latest notable innovations with the launch of the Roadster and the Club Swing.

1998: The range begins to decline, shrinking to 7 models: series Club (Club, VR, VR Tex Mex, Club Swing), 51V, Hard Rock et Magnum Racing.

2002: End of production of the 51s, due to the application of the anti-pollution standard Euro 2.

2003 : End of marketing.

Technical Details

Cycle parts

It is a monocoque steel structure including an egg-shaped tank elongated in the diagonal tube. An emergency fuel reserve was provided. All versions had shocks in the rear, which were more angled than on the Series 50. According to the models, they were with hidden springs, visible springs for the "young" ranges and certain top-of-the-range series even had the right to gas cylinder hydraulic shock absorbers as standard. separate.

Wheels were spoked on early models as well as utility series. Appeared in 1979 aluminum spoke rims on the 51 model Super, following the fashion of young users of the time.

The braking was assured par control drums par cable whose diameter and efficiency have continued to increase throughout history, without equaling the disc brakes of which only a few rare models intended for racing have been fitted as standard.

ENGINE

The 51 family engine is a distant derivative of the venerable 7 AV block from the 1950s. However, it inaugurated a strong technical evolution with admission par valves in the crankcase and three transfers. Horsepower was up from 2 to 3 DIN horsepower. In the mid-1980s an electronic ignition became widespread greatly improving reliability, then a cooling system par liquid as standard on certain ranges. The 12mm diameter carburetors saw their size increase to 14mm. The typical looking "blunderbuss" shaped exhausts have been gradually replaced.ar a pot of relaxation of the type " Cobra HAS". Towards the middle of the 1980s, the starting system became kick-started on sports versions, abandoning pedaling when moped regulations permitted it.

Some 51s (like the VR) benefited from an automatic variable speed transmission that was already fitted to the 7 AV engine. This replaced the transmission par clutch.