Ducati test 'fuel saving' clutch again

Under the 2007 MotoGP regulations, the fuel allowance has been reduced by one litre to 21 litres.

Ducati test rider Vittoriano Gaureschi has been testing the clutch set-up over the past two seasons. It was first used by Carlos Checa and Loris Capirossi at the 2005 season opener.

The system disengages the clutch completely when the rider brakes hard for a corner, for example a hairpin at the end of a long straight.

Instead of the engine revving through the down changes and therefore using fuel, the revs sit at tick over level until a speed has been reached where the rider opens the throttle to power through the corner. Once this demand has been made, the engine matches its revs to the gear/wheel speed.

To trackside observers, as soon as the rider lets off the throttle, the bikes become nearly silent with just a low level of engine and airflow noise. Then, as the rider is tipping into the corner, the exhaust note returns to normal.

Retarding a MotoGP bike from high speeds without engine braking can be a problem, but not so at lower speeds when the power of the carbon brakes can easily lift the rear wheel off the ground.

The difficulty for engineers is reportedly fine tuning the software to kick the revs back in at the right time without completely unsettling the rider.

The lower speed of crank rotation (inertia) when the engine is idling may also change the feeling of a bike for riders, but the issue of crank rotation direction has been considered something of a 'black art' in recent years.