Motorcycle engine cooling system

A motorcycle having a water-cooled engine. The cooling system includes a radiator located in a hollow front leg shield of the motorcycle. The radiator may be positioned on one side of the down tube while a radiator tank is located on the other. A damper mechanism is disclosed which allows selected flow of heated air from the radiator to be directed toward the rider for warmth. Alternately, heated air flows from the radiator downwardly from the hollow interior of the front leg shield.

BACKGROUND OF THE INVENTION 
The field of the present invention is water cooling systems for vehicles 
and particularly motorcycles. 
Cooling systems for motorcycles including large motorcycles, motor 
scooters, motor bikes and the like have generally employed air-cooled 
engines. Air cooled engines have generally been found lighter in weight, 
less complicated and more compact. Such attributes are generally 
advantageous on motorcycles of all types because of the need for 
lightweight and compact design. Recently, it has been found advantageous 
in certain situations to employ a water-cooled system. Reference here to 
water-cooled systems is intended to encompass such systems whether using 
water or other form of liquid coolant. Water-cooled systems are more 
efficient in maintaining a uniform temperature. However, such systems 
generally require more space and are heavier. 
More space is required for both the radiator and the air flow path to and 
from the radiator. Furthermore, the coolant and the radiator itself add 
additional weight. In light of the stringent demands for compactness and 
lightness, optimum arrangements for maximum radiator efficiency in the 
most compact design and balanced arrangement is necessary. 
SUMMARY OF THE INVENTION 
The present invention pertains to a water-cooled cooling system for a 
motorcycle exhibiting a compact arrangement with efficient weight 
distribution. A radiator is positioned within the hollow interior of a 
front leg shield to obtain the benefits of efficient air flow, maximum 
space utilization and efficient weight distribution. With this 
arrangement, the radiator may be positioned in one of multiple positions 
within the hollow front leg shield to provide maximum space utilization. 
Where the motorcycle includes a front luggage carrier, the radiator may be 
mounted low for air flow about the front wheel. Under such circumstances, 
the center of gravity of the motorcycle is lowered concurrently. With a 
higher mounting position, selectable heated air flow may be directed 
efficiently to the rider when desired. 
Accordingly, it is an object of the present invention to provide an 
improved water-cooled cooling system for a motorcycle having a front leg 
shield. Other and further objects and advantages will appear hereinafter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turning in detail to the drawings, and particularly the embodiment of FIGS. 
1, 2, 3 and 6, a motorcycle is illustrated of the type having a main body 
10, a seat 12, a front wheel 14, a rear wheel 16 and a steering and handle 
grip assembly 18. A water-cooled engine 20 is located generally below the 
seat 12 rearwardly of a step floor 22. A down tube 24 forms a front 
portion of the frame of the motorcycle extending downwardly from the head 
pipe (not shown) and rearwardly below the step floor 22. At the front of 
the motorcycle, a front leg shield 26 protects the rider from frontal air 
flow. 
The front leg shield 26 includes a front wall 28 and a rear wall 30. The 
front and rear walls 28 and 30 are roughly concave such that when 
assembled they form a hollow interior 32. The hollow interior 32 generally 
extends from near the steering and handle grip assembly 18 downwardly to 
the step floor 22. Thus, a cavity is formed through that link. An opening 
34 in the front wall 28 of the leg shield 26 provides room for the front 
wheel 14 and the associated front fender 36. 
Located within the hollow interior 32 of the front leg shield 26, beneath 
the step floor 22 and at the water-cooled engine 20 is an engine cooling 
system. A radiator 38 is located within the hollow interior 32 of the 
front leg shield 26. The radiator 38 is fixed to the down tube 24 and the 
front wall 28 by means of brackets 40 and 42 and fasteners 44. A radiator 
tank 46 is held in a frame 47 and connected to the radiator 38 by 
conventional means including a tube 48. Communication between the radiator 
38 and the water jacket of the engine 20 is provided by means of tubes 50 
and 52. A water pump 54 induces flow through the system. The tubes are 
shown to be separately directed through the structure. However, the down 
tube 24 may be employed to either carry one or both of the tubes or to 
act, when sealed at its ends, as one of the liquid carrying tubes itself. 
The lateral positioning of the radiator tank 46 and the radiator 48 on 
either side of the down tube 24 provides a balance of weight on either 
side of the center line of the motorcycle. The location of the radiator 38 
as well as the radiator tank 46 at the front of the motorcycle helps to 
distribute the weight load of the vehicle. Alternatively, two radiator 
elements may be positioned to balance the motorcycle. By locating the 
radiator 38 in the upper part of the hollow interior 32, unobstructed flow 
of air is received with the motorcycle in motion. Furthermore, vents may 
be advantageously located to provide heated air to the rider as will be 
more fully described below. 
Looking to the provision for air flow to the radiator 38, an inlet opening 
56 is disposed directly in front of the radiator 38 and includes louvers 
58 which provide an aesthetic appearance and air flow direction where 
applicable. The location of the inlet opening 56 allows it to receive 
direct air flow with the motorcycle moving forward. This air flow is then 
immediately directed to the radiator 38 for efficient heat transfer. 
Located rearwardly of the radiator 38 within the hollow interior 32 is a 
baffle 60. The baffle 60 divides the hollow interior 32 of the leg shield 
26 into first and second volumes. The first and larger volume contains the 
radiator tank 46, the down tube 24 and the radiator 38. The second and 
smaller volume provides a passageway for the air exhausting from the 
radiator to pass downwardly in front of the back wall of the leg shield 26 
as indicated by the arrows in FIG. 2. To provide communication between the 
two volumes such that air exhausted from the radiator 38 may pass directly 
into the passageway of the second volume, the baffle 60 includes a port 
62. A small air outlet 64 allows venting of the upper portion of the 
hollow interior 32 when air is not forced downwardly due to the forward 
motion of the vehicle. 
Associated with the rear wall 30 of the front leg shield 26 is a 
selectively closable vent 66. This vent may assume a plurality of 
configurations. Two configurations are illustrated in FIGS. 4A, B and 5A, 
B. The device illustrated in FIGS. 4A and 4B are in the form of a damper 
having pivotally mounted plates 68 and 70. The plates are coupled to a 
lever 72 which may be actuated by a knob 74 through a slot 76 in the back 
wall 30 of the front leg shield 26. The vent 66 may be actuated through 
simple motion of the knob 74 to allow or restrict exhausted flow through 
the radiator 38 to the rider. 
In FIGS. 5A and 5B, a rotary damper is illustrated including a knob 78 
which actuates the vent plate 80 to selectively expose or cover vent holes 
82. 
Turning then to the embodiment of FIGS. 7 and 8, a similar motorcycle 
structure is illustrated with corresponding elements to that of the first 
embodiment being referenced by corresponding numbers. The radiator 38 is 
located in a lower part of the front leg shield 26 as can best be seen in 
FIG. 7. This position places the radiator 38 rearwardly of the front wheel 
14 and the radiator 38 extends downwardly to below the top of the front 
wheel. In this location, the center of gravity of the motorcycle is 
lowered as weight is located in the lower position. The inlet opening 56 
allows air flow which flows adjacent to the front wheel 14 to be directed 
at the radiator 38 which may be exhausted through port 66. A forwardly 
extending mud guard 84 extends into a position between the rear portion of 
the front wheel 14 and the radiator 38 to prevent mud from clogging the 
radiator. 
The location of the radiator 38 also makes possible the positioning of a 
luggage carrier 86 forwardly of the steering mechanism 18 and above a 
front fender 36. 
Turning next to the embodiment of FIGS. 9 and 10, a radiator 38 positioned 
in the lower portion of the front leg shield 26 is illustrated. Once 
again, corresponding numbers apply to this embodiment as to the 
embodiments previously discussed. In the embodiment of FIGS. 9 and 10, the 
radiator 38 is counterbalanced by a radiator tank 46. Additionally, the 
front fender 36 pivots with the wheel 14 such that protection from mud and 
the like is accomplished by means of the fender 36 itself. An inlet 
opening 56 allows air to be directed into the hollow interior 32 of the 
front leg shield 26 for direction through the radiator 38 and out the 
outlet opening 88. 
Accordingly, three principal embodiments of a motorcycle incorporating a 
radiator mounted in a hollow interior of a front leg shield for 
advantageous and efficient employment of a water-cooled system is 
disclosed. While embodiments and applications of this invention have been 
shown and described, it would be apparent to those skilled in the art that 
many more modifications are possible without departing from the inventive 
concepts herein. The invention, therefore, is not to be restricted except 
in the spirit of the appended claims.