Intake system for motorcycle engines having V-shaped cylinder arrangement

• US 4,321,978 A
• Filed: 07/13/1979
• Issued: 03/30/1982
• Est. Priority Date: 07/15/1978
• Status: Expired due to Term

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Kurai, Nobuyoshi, Tominaga, Nobuyoshi, Suzuki, Sadahide, Ueno, Hagime
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): McGiehan, Donn
• Application Number:
  US06/057,268
• Time in Patent Office: 991 Days
• Field of Search: 180/219, 180/225, 123/55 R, 123/55 VF, 123/52 MV, 123/59 PC, 123/73 A, 55/DIG. 28, 55/385 B
• US Class Current: 180/225
• CPC Class Codes: B62K 11/04 characterised by the engine being between front and rear wheels
• CPC Class Codes: B62K 19/30 Frame parts shaped to receive other cycle parts or accessories axle suspensions B62K25/00
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: F02B 61/02 for driving cycles
• CPC Class Codes: F02B 75/22 with cylinders in V, fan, or star arrangement
• CPC Class Codes: F02M 35/02 Air cleaners
• CPC Class Codes: F02M 35/10183 Engines having intake ducts fed from a separate carburettor or injector, the idling system being considered as a separate carburettor
• CPC Class Codes: F02M 35/116 for engines with cylinders in V-arrangement or arranged oppositely relative to the main shaft
• CPC Class Codes: F02M 35/162 Motorcycles; All-terrain vehicles, e.g. quads, snowmobiles; Small vehicles, e.g. forklifts

Abstract

A motorcycle engine having a V-shaped cylinder arrangement in which a space is defined between the fore and aft cylinders. Carburetors for the fore and aft cylinder are disposed in the space between the cylinders and an air filter is located behind the engine. The motorcycle has a frame which is formed with an inside cavity connected with the air filter and the carburetors so that the inside cavity constitutes a part of the intake passage.

Claims

1. A motorcycle comprising a frame, an engine mounted on said frame and including at least one fore cylinder and at least one aft cylinder which are arranged in a V-shaped configuration with a laterally-extending space therebetween, each cylinder having intake port means formed at a side facing into said space, carburetor means disposed in said space and connected with said intake port means in the cylinders, said frame having a closed cavity at least at a portion which is located above the engine, said frame being formed with inlet and outlet port means respectively leading into and out of the cavity, said outlet port means being connected with said carburetor means so that intake air is passed through the cavity in the frame to the carburetor means, and air filter means for passing therethrough the intake air before it is introduced into the closed cavity, said air filter means being disposed behind the engine and mounted on the frame and said inlet port means of the frame is connected with said air filter means so that the intake air is passed from the air filter means through the cavity in the frame to the carburetor means, said air filter means being of a box type configuration having a side cover and a back wall which are connected together to constitute a closed box, said back wall being provided with air inlet and outlet ports and supporting an air filter element disposed between the inlet and outlet ports so that air is passed from said inlet port through the air filter element to the outlet port.

2. A motorcycle in accordance with claim 1 in which said inlet port of the air filter means is associated with an upwardly directed inlet pipe so as to avoid induction of warm air which has been heated by the engine.

3. A motorcycle in accordance with claim 1 in which separate carburetors are provided respectively for the fore and aft cylinders and the carburetors are arranged in a side-by-side relationship.

4. A motorcycle in accordance with claim 3 in which the fore and aft cylinders are transversely offset with each other.

5. A motorcycle according to claim 1 in which said closed cavity is spaced from said cylinders to avoid heating of air in said cavity by said cylinders.

6. A motorcycle comprising;

a frame, an engine mounted on said frame and including at least one fore cylinder and at least one aft cylinder which are arranged in a V-shaped configuration with a laterally-extending space therebetween, each cylinder having intake port means formed at a side facing into space, a pair of independent carburetor means, one respective to a fore and one to an aft cylinder, disposed in said space and independently connected with a respective one of said intake port means of a respective one of said cylinders, said frame having a closed cavity at least at a portion which is located above the engine, said frame being formed with inlet port means leading into said cavity, and a pair of outlet port means, each said outlet port means being connected with a respective one of said carburetor means so that intake air is passed through the cavity in the frame to said outlet means, and independently to each of said carburetor means, and air filter means for passing therethrough the intake air before it is introduced into the closed cavity, said aft cylinder having an intake passage extending forwardly through said carburetor means and connected with said cavity at a front portion thereof, said fore cylinder having an intake passage extending rearwardly through said carburetor means and connected with said cavity at a rear portion thereof.

7. A motorcycle in accordance with claim 6 in which said air filter means is disposed behind the engine and mounted on the frame, and said inlet port means of the frame is connected with said air filter means so that the intake air is passed from the air filter means through the cavity to the carburetor means, said air filter being of a box type configuration having a side cover and a back wall which are connected together to constitute a closed box, said back wall being provided with air inlet and outlet ports and supporting an air filter element disposed between the inlet and outlet ports so that air is passed from said inlet port through the air filter element to the outlet port.

8. A motorcycle in accordance with claim 7 in which said inlet port of the air filter means is associated with an upwardly directed inlet pipe so as to avoid induction of warm air which has been heated by the engine.