Claims
- 1. A motorcycle, comprising:
a vehicle body frame; a swing arm supported at a front end portion thereof for rocking motion on said vehicle body frame; an axle of a rear wheel supported for rotation at a rear end of said swing arm; a cylinder head, said cylinder head being provided on an engine body, said engine body being supported on said vehicle body frame forwardly of said rear wheel; a rear end exhaust portion of an exhaust system connected to said cylinder head is disposed at a position higher than said axle; and an exhaust control valve for adjusting the flow area in an exhaust pipe which forms part of said exhaust system is disposed in said exhaust pipe, wherein said exhaust control valve is disposed forwardly and upwardly of said axle of said rear wheel.
- 2. The motorcycle according to claim 1, wherein in a low or medium speed rotational region of the engine, said exhaust control valve is operated to the closing side in order to utilize an exhaust gas pulsation effect in the exhaust system to raise the output power of the engine, and in a high speed rotational region of the engine, the exhaust control valve is operated to the opening side in order to reduce the exhaust gas flow resistance in the exhaust system to raise the output power of the engine
- 3. The motorcycle according to claim 1, wherein the exhaust control valve is located in an increased diameter portion of the rear end exhaust portion.
- 4. The motorcycle according to claim 3, wherein the exhaust control valve is secured to a valve shaft supported for rotation on the increased diameter portion of the rear end exhaust portion.
- 5. The motorcycle according to claim 4, wherein a bearing housing having a bottomed cylindrical shape is securely mounted on the increased diameter portion, and the valve shaft is supported at one end thereof on the bearing housing through a first seal member.
- 6. The motorcycle according to claim 5, wherein the other end of the valve shaft projects from the increased diameter portion with a second seal member interposed between the increased diameter portion and the valve shaft, and a driven pulley is secured to the projecting end of the valve shaft.
- 7. An exhaust system for a motorcycle, comprising:
an exhaust pipe, said exhaust pipe being connectable to an engine of the motorcycle, a rear end exhaust portion of the exhaust pipe being mountable at a position higher than an axle of a rear wheel of the vehicle; and an exhaust control valve for adjusting the flow area in the exhaust pipe, said exhaust control valve being disposed in said exhaust pipe, wherein said exhaust control valve is disposed forwardly and upwardly of the axle of said rear wheel.
- 8. The exhaust system according to claim 7, wherein in a low or medium speed rotational region of the engine, said exhaust control valve is operated to the closing side in order to utilize an exhaust gas pulsation effect in the exhaust system to raise the output power of the engine, and in a high speed rotational region of the engine, the exhaust control valve is operated to the opening side in order to reduce the exhaust gas flow resistance in the exhaust system to raise the output power of the engine
- 9. The exhaust system according to claim 7, wherein the exhaust control valve is located in an increased diameter portion of the rear end exhaust portion.
- 10. The exhaust system according to claim 9, wherein the exhaust control valve is secured to a valve shaft supported for rotation on the increased diameter portion of the rear end exhaust portion.
- 11. The exhaust system according to claim 10, wherein a bearing housing having a bottomed cylindrical shape is securely mounted on the increased diameter portion, and the valve shaft is supported at one end thereof on the bearing housing through a first seal member.
- 12. The exhaust system according to claim 11, wherein the other end of the valve shaft projects from the increased diameter portion with a second seal member interposed between the increased diameter portion and the valve shaft, and a driven pulley is secured to the projecting end of the valve shaft.
- 13. A motorcycle, comprising:
an axle of a rear wheel supported for rotation at a rear end of a swing arm; an exhaust pipe, said exhaust pipe being connectable to an engine of the motorcycle, a rear end exhaust portion of the exhaust pipe being mounted at a position higher than an axle of a rear wheel of the vehicle; and an exhaust control valve for adjusting the flow area in the exhaust pipe, said exhaust control valve being disposed in said exhaust pipe, wherein said exhaust control valve is disposed forwardly and upwardly of the axle of said rear wheel.
- 14. The motorcycle according to claim 13, wherein in a low or medium speed rotational region of the engine, said exhaust control valve is operated to the closing side in order to utilize an exhaust gas pulsation effect in the exhaust system to raise the output power of the engine, and in a high speed rotational region of the engine, the exhaust control valve is operated to the opening side in order to reduce the exhaust gas flow resistance in the exhaust system to raise the output power of the engine
- 15. The motorcycle according to claim 13, wherein the exhaust control valve is located in an increased diameter portion of the rear end exhaust portion.
- 16. The motorcycle according to claim 15, wherein the exhaust control valve is secured to a valve shaft supported for rotation on the increased diameter portion of the rear end exhaust portion.
- 17. The motorcycle stem according to claim 16, wherein a bearing housing having a bottomed cylindrical shape is securely mounted on the increased diameter portion, and the valve shaft is supported at one end thereof on the bearing housing through a first seal member.
- 18. The motorcycle according to claim 17, wherein the other end of the valve shaft projects from the increased diameter portion with a second seal member interposed between the increased diameter portion and the valve shaft, and a driven pulley is secured to the projecting end of the valve shaft.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2003-095109 |
Mar 2003 |
JP |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2003-095109, filed in Japan on Mar. 31, 2003, the entirety of which is incorporated herein by reference.