In the seventies of the last century, the Wankel engine seemed to break through in motorcycle land. There were over 30 licensees at one point. NSU was the first licensee of the 'Drehkolbenmotor' and made the simpler 'Kreiskolbenmotor' from it. And it became world famous as a 'Wankel engine'. Fichtel & Sachs became the second licensee and made better and better 'Wankel engine blocks' and blocks.
Ideal for motorcycles
In the motorcycle world, the idea of the Wankel engines had also landed. The Wankel engine is a power source without a piston bouncing up and down in a cylinder. Without crankshaft, valves and valve actuation. Besides the rotating rotor, there are actually no moving parts in the shaky block. The compact and relatively powerful engine therefore seemed ideal for use in motorcycles. In addition, the Wankel motor runs very vibration-free. In short: what could actually stand in the way of a major breakthrough?
In 1974 Hercules came out with the W2000
But the first prototype had already been shown in 1970. Fichtel & Sachs made series production oriented Wankel engine blocks. Within a few years, Fichtel & Sachs AG became the leading manufacturer of Wankel engines. In total, more than 100.000 Wankel engines were made.
From the snow onto the road
The success in the vehicle corner started when someone mounted a Fichtel & Sachs Wankel engine in a snowmobile and immediately won a competition with it. That was the start of a short period in which Wankel engines became popular in this branch of sport. And at Hercules, they asked Sachs to supply some of those snowmobile engines so the techs could figure out how to build a motorcycle around them. Initially, the rear frame, gearbox and shaft drive of a BMW R27, including the shaft drive, were used. But that approach turned out to be too expensive. The cardan transmission expired. To save costs, an existing six-speed Rotax transmission was used. This gave the Wankel a regular chain drive.
Hercules or DKW?
The final Hercules (the brand name for mainland Europe and for export to the United States) had many parts from the shelves that other German engine makers of the time also bought from. You could also find the counters and the rear light on Zündapps. The controls and the Ø32 mm Bing vacuum carburettor, but also the indicators, for example, were identical to those of BMW. There was even the BMW emblem on the glass of the turn signals.
Before production started, a pre-production batch of 50 pieces was made.
The initial problems because the power source of a motorcycle is loaded differently than that of a snowmobile were already solved by then. At the front of the Hercules was a Grimeca disc and the exhaust system was duplicated for aesthetic reasons - and to get rid of as much engine heat as possible as quickly as possible. Suspension and damping came from Ceriani, with the front fork being the expensive version of Ceriani (recognizable by the 'hollow' triple clamp).
Performance was fair to good
The fuel consumption was not such an issue then, but was above the norm. The fact that – from 1976 – no more mixing lubrication had to be refueled could no longer save the story. The almost 300 cc wobbly cost about the same as a 500 cc Japanese four-cylinder engine.
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- The Hercules W2000, the smallest Wankel