1. Check the clutch pedal stroke - the pedal should move smoothly, without jamming, throughout the entire working stroke.
2. Also check that there is no slippage or jerking during clutch operation, then adjust the drive cable.
3. If a lot of effort is needed to disengage the clutch, then first check the integrity of the cable and the correctness of its passage along the track, then remove the pedal and lubricate the axle (see subsection 8.3 and subsection 8.4).