Muffler assembly of internal combustion engine

A muffler assembly of an internal combustion engine provided with an exhaust gas port, the muffler assembly being connected during use to one end of an exhaust pipe which has another end connected to the exhaust gas port of the engine, said muffler assembly comprising:

• an inner casing in which is defined a first expansion chamber into which the one end of the exhaust pipe is inserted;
• an outer casing disposed outside the inner casing so as to define second and third expansion chambers between the inner and outer casing;
• first baffle pipe means disposed so as to mutually communicate the first and second expansion chambers;
• second baffle pipe means disposed so as to mutually communicate the second and third expansion chambers;
• and
• tail pipe means disposed so as to communicate the third expansion chamber and an outside of the outer casing;
• wherein exhaust gas from the exhaust gas port of the engine is first introduced into the first expansion chamber of the inner casing, then flows into the second and third expansion chambers in the outer casing through the first and second baffle pipe means, and is finally exhausted through the tail pipe means.