The Honda SH Mode 125 is equipped with a three-way catalyser sited at the back of the exhaust pipe within the muffler.

This location provides an ideal balance between performance and fuel efficiency with improved exhaust purification and reduced CO, HC and NOx output.

To achieve such efficiency the O2 lambda sensor detects oxygen concentration in the exhaust and PGM-FI supplies the engine with the optimal fuel/air ratio.