Piston ring set for Yamaha Jog scooters. Piston rings seal the piston in the cylinder: they hold compression and keep oil out of the combustion chamber. The rings match the piston size.
Replace them if compression drops, hot starting is poor, oil consumption rises and bluish smoke comes from the muffler. The +0.50 size is an oversize: rings enlarged by 0.50 mm are matched to a rebored cylinder and a piston of the same size.
