Dried out starter
Usually a sign of a long period of non use, just remove the starter cover, get some WD40 or Chain lube and squirt it onto the bearing on the dome shaped cover over the starter ring, careful not to overdo it or your clutch will slip!!!!!
Removal is simple, undo the two nuts & bolts visible at the domed shaped cover end after you have disconnected the battery & leads to the motor, Its really is a piece of pxxs. Reg