In two-stroke cycle engines, the piston and piston ring slide over not only the cylinder wall but also the cylinder ports. This study investigates whether piston rings project and get caught in the cylinder ports. We installed strain gauges, on the bottom sides of piston rings, over the intake and exhaust ports, and plotted the variation of strain per cycle, while running the engine. By examining the variation in strain on the bottom of the piston ring, we clarified that our piston ring indeed became momentarily caught in the cylinder ports.