It is due to offensive engagement of the clutch. Most of the drivers take it as a power of their machines. If the forward jumping of the bike becomes habitual then you have to think it as a clutch judder. You can feel the judder as an unsmooth engagement with vibration that causes the vehicle to suddenly jump forward. It is not at all result of worn out clutch plates. So dont change the clutch plates on the spot if somebody suggests you as remedy of clutch judder.
Possible Causes and Remedies:
Clutch judder is the result of misalignments or under tightened blots. Misalignment could be possible between plates, bearings and shafts, locks and pressure plates, spring seats and housing. Loose housing bolts, loose housing on flywheel, worn out shaft splines can also produce clutch judder. Sometimes engagement becomes jumpy because of distorted clutch plates also. In that case you don?€™t have any other options, change the clutch plates.