How do I remove and change the roller belt variator of the BMW C600 and C650?

Unscrew all the screws with a 25 mm Torx spanner so that the fairings covering the soundproofing and variator cover can be removed. Remove the footrest support.

Unscrew all the screws with a 30 mm Torx spanner so that the soundproofing cover can be removed and the variator cover can be accessed.

Unscrew all the screws with a 30 mm Torx spanner so that the variator cover can be removed and the variator can be accessed.

Place the Easyboost tool on the variator to lock it. Unscrew the shaft nut using the second Easyboost spanner or the ratchet with a 34 mm socket.

The variator can now be easily removed, together with the variator cap, rollers and hub.

Place the Easyboost spanner on the torque drive to lock it in place. Unscrew the shaft nut from the shaft using the pawl with a 34 mm bush (clockwise as the pitch is reversed).

Then the torque drive-clutch-belt assembly is removed. The latter is easily released from the torque drive.

Before loosening the clutch nut, a mark is made on the felt pen so that it can be tightened again in the same original position. To easily remove the clutch nut, use the Easyboost tools. First, loosen the clutch nut by 1/4 turn with the Easyboost spanner and the open-end spanner by tapping it with a hammer.

Once the nut has been released, the push spring disassembly tool is inserted following the instructions in the manual. This operation will allow the clutch nut to be released by exerting a slight pressure on the thrust spring. Caution: As the clutch is already in the end position, no attempt should be made to compress the spring any further.

The nut can now be removed by hand as the clutch no longer exerts pressure on it.

All that remains to be done is to unscrew the axle nut to gradually release the spring without risk.

The spring is disassembled, it can now be replaced by a new and/or harder model to increase torque and recovery.

For reassembly, the operation is repeated in reverse order. The tool is put back in place to compress the thrust spring.

Repeat the same procedure as for disassembly, inserting the tool for locking the torque drive. Using the open-end spanner, tighten the clutch nut until the previously drawn marks are aligned.

The arrows on the belt indicate the direction of rotation of the motor.

Insert the belt into the torque drive and mount the assembly on the shaft.

Insert the variator, hub, cap and rollers on the shaft.

The variator nut must be tightened to a torque of 100 Nm +/- using the Easyboost lock spanner and a torque spanner with a 34 socket. Do not forget to fold down the safety washer.

To tighten the nut of the torque drive in the reverse direction, it is necessary to turn the end of the torque spanner. To do this, unscrew the torque spanner plate, turn the tip over and then replace the plate with the 2 screws.

After reassembling the variator housing, the nut of the torque corrector can be tightened to 100 Nm.

All that remains to be done is to tighten all the screws on the dimmer cover before refitting the soundproofing cover.

Tighten all the screws of the soundproofing cover before refitting the fairings.

All that remains to be done is to tighten all the fairing screws and refit the footrest support to complete the operation.