BMW Motorrad has revealed a concept stunt bike based on a single cylinder study. Dubbed Stunt G 310, the motorcycle has been designed with the input of four-times World and European stunt riding champion, Chris Pfeiffer.
The engine’s special feature is the cylinder which is inclined towards the rear and the cylinder head which is rotated by 180 degrees. This permits better placement of the engine in the motorcycle and a short wheelbase in spite of the long swinging arm.
The designers say by shifting the intake area towards the front while also moving the exhaust system towards the rear it was possible to place the rear silencer in an upright standing position underneath the seat between engine and spring strut. In this way the silencer gets enhanced protection, thereby giving the stunt rider increased freedom of movement.
Stunt-specific modifications include a lockable throttle that grants continued propulsion even when the rider’s hand has to let go of the throttle grip. In addition a slightly altered gear ratio delivers increased propulsive force to the rear wheels at low engine speeds while the intentionally oversized rear wheel brake means reliable deceleration.
A second, even larger rear wheel brake allows the rider to brake the rear wheel using only his middle finger, in case his right foot is not on the footrest in certain stunts. The additional brake lever is specially placed on the left side of the handlebars and can be operated at the same time as the clutch. So-called axle pegs on the front axle and in the seat area give the rider additional options for placing his feet. The distinctive red crash bars, meanwhile, provide additional protection for the engine.
A final and key design element is the “stunt tail” which is milled from solid aluminium and features an opening in the centre that offers the stunt rider a hold for his foot. Together with the non-slip seat, the aluminium component also means a more stable seating position when riding owing to its shape.
“Stunt riding is a demanding and multi-faceted sport. Ideally you need a compact, agile bike which is also stable and robust at the same time. You have to achieve the ideal balance between aggressiveness and control”, says Pfeiffer.
Source: BMW Motorrad