Rotax V990

Slipper Clutch

Pneumatic Power Clutch/slipper clutch/PBTL System details are in this apriliaforum post.

PBTL SYSTEM

The PBTL system on the RSV 1000 reduces the ‘braking’ torque transmitted by the engine during deceleration.

OPERATING PRINCIPLE:

Line 1 is connected to the intake passage whereas line 2 – downstream of the retaining valve – is connected to the airbox via the throttle valve. Line 3 links line 2 to the airbox when the throttle valve opens to an angle greater than 10-12 degrees.

During deceleration, the system configuration is as shown in the figure.

The negative pressure in the intake passages is transmitted to the clutch membrane via line 1+2.

The ‘retaining’ valve (non-return) comes into play and stabilises the pressure in the line.

Consequently, the clutch discs slip and reduce the torque.

During acceleration (throttle valve >12°), the valve, connected on the throttle unit axis, links up line 2 with the airbox, thus cancelling out the pressing effect on the clutch unit and taking the clutch pack back to its original position.