most times..after a bike has been sitting for some time..the clutch disk will sieze together..after you ride it for awhile..most will come undone..not always mind you..but..they will work loose...what year is it ?..if it's not too old..this may solve your problem..if not..then just put some new clutch disk in it..problem solved !!..also would like to add..the centrifugal clutch arms will sieze up too..after some ridding..they will work loose also.