Replace your TM36, TM40, or HS40 top cover gaskets with only genuine Mikuni parts.  The TM36/39 top cover gaskets are made from gasket material that resists weathering, heating cycles, and gasoline...even after many years of use.  Using Mikuni top cover gaskets ensures an exact fit and proper function in all conditions.  The gasket fits all Mikuni TM36, TM40, and HS40 carburetors.