JPH0133782Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of an exhaust expansion pipe for a motorcycle engine.

[Technical background of the invention and its problems]

The exhaust expansion pipe connected to the exhaust port end of the engine is
A certain length is required because it uses the pulsation of exhaust gas to increase engine output. Normally, on a motorcycle, the engine is passed from the front to the bottom and connected to the muffler, but this is too short due to the overall length of the vehicle. So, as shown in Figure 1,
Exhaust expansion pipe C connected to exhaust hole B of engine A is directed obliquely forward from exhaust hole B, extends to one side of the front side of frame down tube D on the front side of engine A, and is bent into a U-shape there. , extends above the other rear side of the down tube D, is bent further rearward, passes through the upper part of the engine A, and is connected to the muffler E. Even if this is done, the length may still be insufficient. Furthermore, in this type, the thick exhaust expansion pipe C reduces the space for accommodating components such as a carburetor and cleaner connected to the rear side of the engine A, which is inconvenient.

[Purpose of invention]

In view of this point, the object of this invention is to obtain an exhaust expansion tube that can be made sufficiently long.

[Structure of the idea]

The present invention will be described below with reference to the embodiments shown in FIGS. 2 and 3.

The exhaust expansion pipe 3 connected to the end of the exhaust hole 2 of the engine 1 passes from the exhaust hole 2 to one side of the down tube 5 of the frame 4 located on the front side of the engine, and exits to the front side of the down tube 5. Bend the above down tube 5 to the other side
extended to the other side. Then, the exhaust expansion pipe 3 is bent into a U-shape on the other side of the down tube 5, returned to one side of the down tube 5, bent rearward on one side of the down tube 5, and passed through the upper part of the engine 1. It extends rearward, and a muffler 6 is connected to the rear end.

In this way, the exhaust expansion pipe 3 extends left and right across the front of the engine, almost between the left and right frames, so the exhaust expansion pipe 3 can be made sufficiently long, and the pulsation of exhaust gas can be effectively utilized. It is possible to increase the output. Furthermore, most of the large diameter portion 3b formed following the small diameter portion 3a of a predetermined length of the exhaust expansion pipe connected to the exhaust hole 2 of the engine 1 can be disposed at the front portion of the engine 1. Since the small diameter portion 3c is formed at the rearward bending portion on one side of the down tube 5 and can be extended rearward in a straight line, there is plenty of space in the rear side of the engine 1 where various parts are installed. The cleaner, etc. can also be made larger, and inspection and removal can be made easier. Moreover, in the front part of the down tube 5, even if the exhaust expansion pipe is extended from side to side, it will not be a hindrance at all.

[Effect of idea]

As explained above, this idea uses a small diameter exhaust expansion pipe whose front end is connected to the end of the engine exhaust hole.
From the exhaust hole, pass through one side of the frame down tube on the front side of the engine and bring it out to the front side of the down tube, extend the exhaust expansion pipe to the other side of the tube, bend it into a U shape again, and bend it backwards on one side of the front part of the down tube. Since the exhaust expansion pipe is extended rearward through the upper part of the other side of the engine, the exhaust expansion pipe can be detoured and made longer in front of the down tube, and the output of the engine can be increased. Furthermore, since the large diameter portion of the exhaust expansion pipe can be disposed in front of the engine, a large space can be secured at the rear of the engine, the cleaner etc. can be made large, and inspection and removal can be facilitated.

[Brief explanation of the drawing]

Figure 1 is a side view showing a conventional example, Figures 2 and 3
The figure shows an embodiment of the present invention, FIG. 2 is a side view,
FIG. 3 is an enlarged plan view of the main part. 1...Engine, 2...Exhaust hole, 3...Exhaust expansion pipe, 4...Frame, 5...Down tube.

Claims (1)

[Scope of utility model registration request] An exhaust expansion pipe whose front end is connected to the exhaust hole end of the engine is brought out from the exhaust hole through one side of the down tube of the frame on the front side of the engine to the front side of the down tube, and the exhaust expansion pipe is extended to the other side of the down tube, An exhaust expansion pipe for a motorcycle engine, characterized in that it is bent into a U-shape again, bent backward at the front side of the down tube, and passed over one side of the engine to extend rearward.