JP2816443B2 - Motorcycle exhaust system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motorcycle exhaust device.

[Conventional technology]

For off-road motorcycles, the exhaust system of the engine is installed at a higher position to increase the road clearance. 3 and 4 show a conventional motorcycle exhaust system. In the figure, an engine cylinder A
Is provided with an exhaust hole B on the front side. And since the magneto chamber C is provided on the left side of the crank chamber and protrudes laterally, the first muffler D connecting the tip to the exhaust hole B is bent rightward and extends rearward through the right side of the cylinder A, It is connected to a second muffler E mounted on the rear right side of the vehicle body. In the case of a water-cooled engine, a radiator F is provided on the front left and right of the vehicle body toward the front, and a water pump G is provided on the right side of the crank chamber.

In addition, completely opposite to this, the magneto chamber C is provided on the left side,
The first muffler D and the second muffler E may be arranged on the left side. Further, as a prior art document of this kind, Japanese Patent Laid-Open No.
There is No. 8 publication.

[Problems to be solved by the invention]

The conventional exhaust device for a motorcycle is configured as described above, and the first muffler D and the water pump G are on the same side, and the water hose connected to the radiator F and the first muffler D are close to each other. For this reason, there has been a problem that the manufacturing cost is high, such as using a heat-resistant rubber for the water hose. Furthermore, since the first muffler D swells outward from the fuel tank attached to the upper portion, there is a problem that the first muffler D easily hits the foot.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a motorcycle exhaust device in which the manufacturing cost is reduced and the exhaust pipe does not contact the foot.

[Means for solving the problem]

In order to achieve the above object, an exhaust device for a motorcycle according to the present invention includes an engine provided with a crankcase substantially at the center of a vehicle body between a front wheel and a rear wheel, and a cylinder inclined forward and upward at a front portion of the crankcase. The intake pipe, the carburetor, and the air cleaner are respectively disposed toward the rear of the vehicle body in the space above the crankcase and at the rear of the cylinder, and an exhaust hole is provided at the front of the cylinder. After the first expansion pipe having one end connected to the exhaust hole of the cylinder is led out from the exhaust hole to the lower front of the cylinder, it is bent to one side of the vehicle body, and the bulging portion is maximized at the upper side of the cylinder, Thereafter, the diameter is gradually reduced toward the rear, and the intermediate exhaust pipe connected to the first expansion pipe is positioned forward of the carburetor and rearward of the cylinder, and passes through the upper space of the intake pipe to the other side of the vehicle body. Bend at The air cleaner passes through a position below the air cleaner when viewed from the side of the vehicle, extends downward, and is connected to a second inflation pipe attached to the vehicle body above the rear wheel.

[Action]

According to the present invention, the first expansion pipe is once turned to the left side of the cylinder, and then passed from the left side to the right side at the rear side of the cylinder, so that the water pump and the water hose arranged on the right side of the crank chamber do not intersect. Further, since the first expansion pipe passes from the left side to the right side of the rear side of the cylinder and crosses the center of the vehicle body, it is difficult for the driver's feet or the like to hit. In the portion where the right side of the first inflation pipe extends rearward, the air cleaner passes under the air cleaner, so that the air cleaner can be easily inspected.

〔Example〕

Hereinafter, an embodiment of a motorcycle exhaust device according to the present invention will be described with reference to FIGS. 1 and 2. FIG.

In the figure, reference numeral 100 denotes an off-road type motorcycle. This motorcycle 100 is provided with a front wheel 102 at a front fork at a front portion of a body 101 and a rear wheel 103 at a rear portion so as to be rotatable. An engine 1 is mounted in a substantially central portion of the engine 103, and an intake pipe, a carburetor, and an air cleaner 7 are provided at a rear portion of a cylinder 2 of the engine 1 on a vehicle body 10.
They are connected to each other toward the rear of 1.

The engine 1 is a water-cooled single-cylinder two-stroke engine in which a cylinder 2 is arranged vertically, and the axis of the cylinder 2 is inclined upward and forward, and an exhaust hole 3 is provided on the front side of the cylinder 2. . A water pump 4 is mounted on the right side of the crank chamber below the engine 1, and a magneto chamber 5 projects on the left side.

The front end of the first muffler 6 is connected to the exhaust hole 3 and is bent leftward at the front side of the cylinder 2 so as to face backward, is made approximately half a circle through the left side of the cylinder 2, and is further bent rightward from the left side at the rear side of the cylinder 2. Through. It is formed in an intermediate exhaust pipe 6a formed of a small-diameter straight pipe, extends rearward through the lower portion and the vicinity of the rear portion of the air cleaner 7, bends upward from that location, and lifts the end thereof to the right rear portion of the vehicle body 101. The second muffler 8 is connected. A radiator 9 is attached to the front left and right of the vehicle body 101 so as to face forward.

The first muffler 6 is mainly composed of an expansion chamber, and is determined to have a volume capable of reducing the back pressure and increasing the output by utilizing the pulsation of the exhaust gas. In addition, the second muffler 8 mainly functions for silencing.

〔The invention's effect〕

As described above, according to the present invention, after the first expansion pipe having one end connected to the exhaust hole of the cylinder is led out from the exhaust hole to the lower front of the cylinder, it is bent to one side of the vehicle body and The bulging portion is maximized, and then the diameter is gradually reduced toward the rear, and the intermediate exhaust pipe connected to the first expansion pipe is located at a position forward of the carburetor and behind the cylinder, and the upper space of the intake pipe is reduced. Through and bend out on the other side of the car body,
After passing through the position below the air cleaner at the side of the vehicle, it extends downward and connects its end to the second expansion tube attached to the vehicle body above the rear wheel, so the first expansion tube is once bent to the left. In this way, it is possible to prevent the water hose and the water hose on the right side from intersecting with each other through the left side of the cylinder to prevent the water hose and the water hose from being inexpensive. Then, at the rear side of the cylinder, the first inflation pipe is turned from left to right so as to pass through the center portion of the vehicle body, so that the first inflation pipe can hardly hit the driver's feet or the like. Furthermore, since the first expansion pipe is passed through the lower side near the air cleaner, the air cleaner can be inspected smoothly and easily.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a motorcycle exhaust system according to the present invention, FIG. 2 is a plan view showing one embodiment of a motorcycle exhaust system according to the present invention, FIG. 3 and FIG. FIG. 3 is a side view of a conventional motorcycle exhaust system, and FIG. 4 is a plan view of a conventional motorcycle exhaust system. 1 ... Engine, 2 ... Cylinder, 3 ... Exhaust hole, 4 ...
... water pump, 6 ... first muffler (first expansion pipe), 6a ... intermediate exhaust pipe, 7 ... air cleaner, 8 ...
… Second muffler (second expansion tube), 100 …… motorcycle, 101
... body, 102 ... front wheels, 103 ... rear wheels.

Claims (1)

(57) [Claims] An engine having a crankcase and a cylinder inclined forward and upward at a front portion of the crankcase is mounted substantially at the center of the vehicle body between the front wheel and the rear wheel, and a space above the crankcase is provided. A motorcycle in which an intake pipe, a carburetor, and an air cleaner are respectively provided toward the rear of the vehicle body at a rear portion of a cylinder, and an exhaust hole is provided at a front portion of the cylinder, one end of which is connected to an exhaust hole of the cylinder. After the first expansion pipe is led out from the exhaust hole to the front and lower part of the cylinder, it is bent to one side of the vehicle body to maximize the bulge at the upper side of the cylinder, and then gradually decreases in diameter toward the rear, and An intermediate exhaust pipe connected to one expansion pipe is bent forward at a position forward of the carburetor and rearward of the cylinder, and at the other side of the vehicle body through an upper space of the intake pipe, so that the side of the vehicle body is viewed from the side of the vehicle. Said d An exhaust system for a motorcycle, characterized in that it extends downward after passing through a position below the cleaner and has its end connected to a second expansion pipe attached to the vehicle body above the rear wheel.