Dual motorcycle exhaust system

Abstract

An exhaust system for an internal combustion engine having a first cylinder and a second cylinder from which pulses of exhaust gas exit and are routed along separate paths towards the exhaust mufflers. The exhaust system independently routes the pulses of exhaust gas from the two cylinders. The exhaust gases that are expelled from the first cylinder are routed through a first exhaust pipe. The exhaust gases that are expelled from the second cylinder are routed through a second exhaust pipe assembly. The second exhaust pipe assembly routes the exhaust gasses from an exhaust port for the second cylinder laterally across the motorcycle to achieve a true dual exhaust system. The second exhaust pipe assembly provides an approximate equal length flow path as compared to the path used by the exhaust gasses that are expelled from the first cylinder.

1 . A motorcycle exhaust system for receiving exhaust gases on a same side of the motorcycle and discharging the received exhaust gases on both sides of the motorcycle over an entire RPM range of the motorcycle, said system comprising: 
 a first exhaust pipe in flow communication with a first cylinder for receiving and routing a first pulse of exhaust gas substantially along only a first side of the motorcycle over the entire RPM range; and    a second exhaust pipe in flow communication with a second cylinder for receiving and routing an entire second pulse of exhaust gas from the first side of the motorcycle and to a second side of the motorcycle over the entire RPM range, wherein the first side and the second side are located on different sides of a vertical plane passing through a centerline of the motorcycle.    
   
   
       2 . An exhaust system according to  claim 1 , wherein the first cylinder and the second cylinder are arranged in a V-Twin configuration, and wherein the vertical plane passes through the first cylinder and the second cylinder.  
   
   
       3 . An exhaust system according to  claim 1 , wherein the second exhaust pipe comprises a bend of at least 180 degrees.  
   
   
       4 . An exhaust system according to  claim 3 , wherein the bend is located on the first side of the motorcycle.  
   
   
       5 . An exhaust system according to  claim 3 , wherein the bend is substantially continuous.  
   
   
       6 . An exhaust system according to  claim 1 , wherein the second exhaust pipe is configured to attach to an original equipment manufacturer (OEM) attachment point of the motorcycle.  
   
   
       7 . An exhaust system according to  claim 1 , further comprising a first muffler connected to and in flow communication with the first exhaust pipe, and a second muffler connected to and in flow communication with the second exhaust pipe.  
   
   
       8 . An exhaust system according to  claim 1 , wherein the second exhaust pipe comprises an upstream pipe and a downstream pipe, wherein the upstream pipe is in communication with the second cylinder and routes the second pulse of exhaust gas from the first side of the motorcycle chassis and towards the second side, and wherein the downstream pipe is in flow communication with the upstream pipe and further routes the second pulse of exhaust gas along the second side of the motorcycle.  
   
   
       9 . An exhaust system according to  claim 8 , wherein the upstream pipe comprises a first elbow in flow communication with the second exhaust port.  
   
   
       10 . An exhaust system according to  claim 9 , wherein the upstream pipe comprises a second elbow in flow communication with the first elbow.  
   
   
       11 . An exhaust system according to  claim 10 , wherein the second elbow comprises a first sub-elbow and a second sub-elbow, and wherein the second sub-elbow is in flow communication with the first sub-elbow.  
   
   
       12 . An exhaust system according to  claim 1 , wherein the length of the first exhaust pipe and the length of the second exhaust pipe are approximately equal.  
   
   
       13 . An exhaust system according to  claim 1 , wherein the length of the first exhaust pipe is within 10% of the length of the second exhaust pipe.  
   
   
       14 . A motorcycle having a first cylinder and a second cylinder, and a dual exhaust system configured for receiving exhaust gas pulses from the first and second cylinders on only a first side of the motorcycle and routing only the exhaust gas pulses received from the second cylinder through the motorcycle and along a second side of the motorcycle over an entire engine operating range of the motorcycle, wherein the first side and the second side are located on different sides of the motorcycle.  
   
   
       15 . A motorcycle according to  claim 14 , wherein the dual exhaust system comprises a first exhaust pipe and a second exhaust pipe, both exhaust pipes being of approximately equal length.  
   
   
       16 . A motorcycle according to  claim 15 , wherein the length of the second exhaust pipe is within 10% of the length of the first exhaust pipe.  
   
   
       17 . A motorcycle according to  claim 14 , wherein the second exhaust pipe comprises a bend of at least 180 degrees.  
   
   
       18 . A motorcycle according to  claim 17 , wherein the bend is located on the first side of the motorcycle.  
   
   
       19 . A motorcycle comprising: 
 a frame;    an engine attached to the frame and having a first cylinder head and a second cylinder head, each containing a cylinder, wherein the first and second cylinder heads exhaust gas on a same side of the engine; and    a dual exhaust system in flow communication with the two cylinder heads and configured to route exhaust gases separately to different sides of the frame over an entire RPM range of the engine.    
   
   
       20 . A motorcycle according to  claim 19 , wherein the dual exhaust system further comprises: 
 a first exhaust pipe having a first inlet end and a first outlet end, wherein the first inlet end is connected to the first cylinder for scavenging and routing exhaust gas away from the first cylinder; and    a second exhaust pipe having a second inlet end and a second outlet end, wherein the second inlet end is connected to the second cylinder for scavenge and routing exhaust gas through the frame, wherein exhaust gases routed through the first and second exhaust pipes are separate from one another.