# US 9,435,247 B2 · Exhaust pipe structure of motorcycle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,247 B2 - Document ID: US9435247B2 - Status: Granted - Kind: B2 - Application number: 14/659,096 - Filed: 2015-03-16 - Published: 2015-09-24 - Granted: 2016-09-06 - Earliest claimed: 2014-03-20 - Assignees: Honda Motor Co., Ltd. - Applicants: Honda Motor Co., Ltd. - Inventors: Takeshi Sakai; Satoshi Matsushima - Web page: https://patentgrep.com/patent/US9435247B2 ## CPC - F01N 13/002: {Apparatus adapted for particular uses, e.g. for portable devices driven by machines or engines} - F01N 13/08: Other arrangements or adaptations of exhaust conduits {(pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005)} - F01N 13/1805: {Fixing exhaust manifolds, exhaust pipes or pipe sections to each other, to engine or to vehicle body (pipe joints in general F16L; fixing auxiliaries in motor vehicles in general B60K)} - F01N 2340/04: Arrangement of the exhaust system relative to a vehicle or parts thereof - F01N 2590/04: for motorcycles - F02B 61/02: for driving cycles - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) ## Abstract An exhaust pipe structure of a motorcycle allowing exhaust air of an exhaust pipe having a branching part to flow into the respective exhaust pipes on the downstream side of the branching part uniformly and smoothly. In an exhaust pipe structure of a motorcycle having an engine attached to a vehicle body frame, an exhaust pipe is connected to an exhaust port of the engine and is provided with a branching pipe that branches into a left-rear-portion exhaust pipe and a right-rear-portion exhaust pipe. A muffler is connected to the left-rear-portion exhaust pipe. A muffler is connected to the right-rear-portion exhaust pipe. The branching pipe is located on a lateral side of a cylinder unit of the engine and above a crankcase cover. ## Claims ### Claim 1 An exhaust pipe structure for a motorcycle having an internal combustion engine which comprises: an exhaust pipe having an elongated circular shape and connected to an exhaust port of the internal combustion engine, said exhaust pipe including a branching part that branches into two branch exhaust pipes; and a muffler connected to each of the branch exhaust pipes; said branching part being located on a lateral side of a cylinder unit of the internal combustion engine and above a crankcase cover and branching rearwardly into said branch exhaust pipes which have circular shaped upstream end portions, the circular shape of the upstream end portions of the exhaust pipes being partially deformed to form flat walls which are in contact with each other, whereby vehicle body space is effectively enhanced. ### Claim 2 (depends on 1) The exhaust pipe structure for use with a motorcycle according to claim 1, further providing that the branching part and parts connected to the front and to the rear of the branching part, in the exhaust pipe, are formed into a linear part having a linear shape and this linear part extends along an upper surface of the crankcase cover, in a side view. ### Claim 3 (depends on 1) The exhaust pipe structure for use with a motorcycle according to claim 1, further providing that the exhaust pipe extends from the exhaust port toward a front side of the motorcycle and then curves rearwardly from the branching part to the branch exhaust pipes; and a section of the branching part is formed into an elongated circular shape, with a long axis of the elongated circular shape inclined to be parallel to a tangent plane to a curving outer circumferential line passing on an outermost circumference of the curving part of the exhaust pipe. ### Claim 4 (depends on 3) The exhaust pipe structure for use with a motorcycle according to claim 3, further providing that one of the branch exhaust pipes passes between a pivot plate and a rear shock absorber to extend rearwardly to be connected to one of the mufflers, and the other of the branch exhaust pipes passes between a rear side of the cylinder unit and a front side of the rear shock absorber and then passes between another pivot plate and the rear shock absorber to extend rearwardly and be connected to the other of the mufflers. ### Claim 5 (depends on 1) The exhaust pipe structure for use with a motorcycle according to claim 1, further providing that one of the branch exhaust pipes passes between a pivot plate and a rear shock absorber to extend rearwardly to be connected to one of the mufflers, and the other of the branch exhaust pipes passes between a rear side of the cylinder unit and a front side of the rear shock absorber and then passes between another pivot plate and the rear shock absorber to extend rearwardly and be connected to the other of the mufflers. ### Claim 6 (depends on 5) The exhaust pipe structure for use with a motorcycle according to claim 5, further providing that the branch exhaust pipes have at least one bending part in a space that is on the rear side of the cylinder unit, on the front side of the rear shock absorber, above a crankcase, and below an intake system. ### Claim 7 (depends on 1) The exhaust pipe structure for use with a motorcycle according to claim 1, further providing that the branching part branches in such a manner that the two branch exhaust pipes are juxtaposed in an upward-downward direction. ### Claim 8 (depends on 7) The exhaust pipe structure for use with a motorcycle according to claim 7, further providing that the exhaust pipe extends from the exhaust port toward a front side of the motorcycle and then curves rearwardly from the branching part to the branch exhaust pipes; and a section of the branching part is formed into an elongated circular shape, with a long axis of the elongated circular shape inclined to be parallel to a tangent plane to a curving outer circumferential line passing on an outermost circumference of the curving part of the exhaust pipe. ### Claim 9 (depends on 7) The exhaust pipe structure for use with a motorcycle according to claim 7, further providing that one of the branch exhaust pipes passes between a pivot plate and a rear shock absorber to extend rearwardly to be connected to one of the mufflers, and the other of the branch exhaust pipes passes between a rear side of the cylinder unit and a front side of the rear shock absorber and then passes between another pivot plate and the rear shock absorber to extend rearwardly and be connected to the other of the mufflers. ### Claim 10 An exhaust pipe structure for a motorcycle having an internal combustion engine attached to a vehicle body frame, comprising: an exhaust pipe connected to an exhaust port of the internal combustion engine and provided with a branching part located on a lateral side of a cylinder unit of the internal combustion engine and above a crankcase cover, that branches rearwardly into left rear portion and right rear portion exhaust pipes provided with respective mufflers, the exhaust pipe extending from the exhaust port toward a front side of the motorcycle and then curving rearwardly to form said branching part which branches rearwardly into said left rear portion exhaust pipe and said right rear portion exhaust pipe, upstream end portions of the left rear portion and right rear portion exhaust pipes being partially deformed to form flat walls which are in contact with each other, and the branching part comprising an elongated circular shape with a long axis of the elongated circular shape being inclined to be parallel to a tangent plane to a curving outer circumferential line passing on an outermost circumference of the curving part of the exhaust pipe. ### Claim 11 (depends on 10) The exhaust pipe structure for a motorcycle according to claim 10, further providing that the branching part and parts connected to the front and to the rear of the branching part, in the exhaust pipe, are formed into a linear part having a linear shape and this linear part extends along an upper surface of the crankcase cover, in a side view. ### Claim 12 (depends on 10) The exhaust pipe structure for a motorcycle according to claim 10, further providing that one of the left rear portion and right rear portion exhaust pipes passes between a pivot plate and a rear shock absorber to extend rearwardly to be connected to one of the mufflers, and the other of the left rear portion and right rear portion exhaust pipes passes between a rear side of the cylinder unit and a front side of the rear shock absorber and then passes between another pivot plate and the rear shock absorber to extend rearwardly and be connected to the other of the mufflers. ### Claim 13 (depends on 12) The exhaust pipe structure for a motorcycle according to claim 12, further providing that the left rear portion and right rear portion exhaust pipes have at least one bending part in a space that is on the rear side of the cylinder unit, on the front side of the rear shock absorber, above a crankcase, and below an intake system. ### Claim 14 (depends on 10) The exhaust pipe structure for a motorcycle according to claim 10, further comprising that the branching part branches in such a manner that the left rear portion and right rear portion exhaust pipes are juxtaposed in an upward-downward direction. ### Claim 15 (depends on 14) The exhaust pipe structure for a motorcycle according to claim 14, further providing that one of the left rear portion and right rear portion exhaust pipes passes between a pivot plate and a rear shock absorber to extend rearwardly to be connected to one of the mufflers, and the other of the left rear portion and right rear portion exhaust pipes passes between a rear side of the cylinder unit and a front side of the rear shock absorber and then passes between another pivot plate and the rear shock absorber to extend rearwardly and be connected to the other of the mufflers. ### Claim 16 (depends on 14) The exhaust pipe structure for a motorcycle according to claim 14, further providing that the branching part and parts connected to the front and to the rear of the branching part, in the exhaust pipe, are formed into a linear part having a linear shape and this linear part extends along an upper surface of the crankcase cover, in a side view.