Mounting structure for an air-fuel ratio sensor in a motorcycle, and exhaust subassembly including same

In a motorcycle of the type having a multi-cylinder engine and an exhaust system comprising a separate exhaust pipe extending from each respective cylinder of the engine, the improvement comprising

• an improved mounting structure in said exhaust system for supportively receiving an air-fuel ratio sensor used for linearly detecting a concentration of oxygen in an exhaust gas stream of the motorcycle during operation thereof,
• said improved mounting structure formed in said exhaust system for supportively receiving a plurality of air-fuel ratio sensors, wherein
• selected exhaust pipes are joined together at least two convergent connectors, each of said convergent connectors having a respective longitudinal axis parallel to the longitudinal axis of the motorcycle,
• each of said convergent connectors having a minimum width portion and wherein an air-fuel ratio sensor is mounted on each of said at least two convergent connectors, respectively, at a central location thereof,
• the fuel-air ratio sensor comprising an element whose output voltage changes in proportion to the oxygen concentration,
• wherein each of said convergent connectors comprises a connector body having an inclined surface, and wherein the air-fuel ratio sensor is mounted on the inclined surface of each of said convergent connectors so as to be inclined towards a rear of said motorcycle,
• wherein said air-fuel ratio sensor is mounted on the inclined surface of each of the convergent connectors so as to be inclined towards a center of the motorcycle in a width direction of the motorcycle;
• and
• wherein said exhaust system is placed on both left and right sides of the motorcycle.

An exhaust subassembly for a motorcycle having a multi-cylinder engine, said exhaust subassembly comprising:

• a plurality of upstream exhaust pipes including a separate exhaust pipe for placement extending from each respective cylinder of the engine, each of said upstream exhaust pipes having a front end portion and a rear end portion;
• a convergent connector attached to the rear end portions of the upstream exhaust pipes, wherein the upstream exhaust pipes are joined together at the convergent connector, said convergent connector having a minimum width portion;
• a pair of downstream exhaust pipes attached to and extending rearwardly from the convergent connector;
• improved mounting structure for supportively receiving an air-fuel ratio sensor used for linearly detecting a concentration of oxygen in an exhaust gas stream of the motorcycle during operation thereof, and wherein said improved mounting structure comprises
• a cylindrical collar centrally provided on said convergent connector proximate said minimum width portion thereof, said cylindrical collar having a threaded opening formed therein;
• a nut disposed in said threaded opening of the cylindrical collar;
• and
• an air-fuel ratio sensor threadably received by said nut disposed in said cylindrical collar, the air-fuel ratio sensor comprising an element whose output voltage changes in proportion to the oxygen concentration,
• wherein said convergent connector comprises a connector body having an inclined surface having said cylindrical collar formed thereon, and wherein the air-fuel ratio sensor is mounted on the inclined surface of said convergent connector so as to be inclined towards a rear of said motorcycle.