This is Yamaha's Technical Paper on developing the mounting system for the 660 engine.... a bit more involved than plunking it on some pieces of rubber, eh? The 686 in the Viking likely has similar development, if a paper exists for it, it is not published. This should get things going in the proper direction for less vibration, and more importantly, holding that engine snug in the chassis.
http://global.yamaha-motor.com/jp/profile/craftsmanship/technical/publish/no32/pdf/browse/gs-03.pdf
Here's the translation....
By the engine rubber mount of
ATV vibration reduction
Technology Introduction ATV Vibration Reduction by Engine Rubber Mount System Shimizu Katsuhisa Katsuhisa Shimizu ● MC Division 5PM second chamber
Introduction
In response to the tailwind of economic boom in the United States , which accounts for about 90 % of the total , ATV market has continued to stretch the near 20% annually in recent years. And than as a business , such as farm work just like the old days , the ATV utility system , Ru Oh Tsu one because the color intensity if physicians as a matter Ri square of quaint taste in it. Results of its , requests to heart The place of Ri power has been growing rapidly in recent years .
The phenomenon vary widely , even if I say ride a word , but because of the reduction of engine vibration , we introduce you with the engine rubber mount technology that was adopted (Figure 1) YFM660FWA NEW GRIZZLY660 participating in this event .
Figure 1 YFM660FWA NEW GRIZZLY
Two
YFM660FWA which was equipped with rubber engine mount system this time , YFM600FWA that was well received in its powerful engine and is equipped with a maximum displacement engine also in the ATV market traditional
Is a full- change model ( Figure 2 ) .
Because it was equipped with rigid single -cylinder engine 600cm3 in conventional cars , in the high speed range
Engine vibration is slightly larger , there was a sense of the competition rival car , which has been working to low vibration of the rubber- mounted engine in recent years , lagging behind somewhat in terms of experience vibration .
In NEW MODEL, for exercise performance and improved maneuverability vehicle , in which the excitation force is increased due to the displacement volume up , it was necessary to push the weight of the vehicle rather . By the rubber mounting of the engine body was aimed for developing the vibration ride comfort can be improved while also lighter therefore . As a development target value , it is the highest amount販車in large displacement ATV currently , was set to equal or greater value and vibration VGL SPORTSMAN500 of PORALIS as a rival of YFM660FWA newly developed . Handle , footrest , fuel specifically
It is those 55 or less in a steady rotation range VGL value of four points fee tank , the seat , the aim of the 60 following maximum value (even at resonance ) .
   1
 
Aim of development
  2 YFM660FWA Figure
  The ATV vibration reduction by rubber engine mount of
ATV Vibration Reduction by Engine Rubber Mount System
 Technology
 excitation force of 3 engine
Table 1 specifications of the engine to rubber mount time, Figure 3 shows the shape of the outline . In one engine balancer shaft with single-cylinder engine , as the main force vibrator ,
( 1 ) The primary inertia couple ( crank axis)
( 2 ) torque variation ( crank axis) ( 3 ) torque variation ( output axis)
I , and the like .
YFM600FWA current was decided to Rated VGL value of the medium and high speed region is not good , and the mount designed to be supported by vibration damping optimal for the primary inertia couple first.
Specifications comparison table of the engine 1
  unit
YFM600FWA
YFM660FWA
Displacement
cm3
595
660
Model
Four-stroke single-axis balancer with a single cylinder
Compression ratio
8.5:1
9.1:1
Reciprocating mass
g
636.3
651.9
Primary inertia couple
kgf · mm 0.121ω2
0.124ω2
Maximum torque
N · m
38
Fifty
Maximum output
kW
23.5
30.5
Body mass
kg
272
272
For excitation force of the torque fluctuation system , since the center frequency is 0.5 next rotation , must be set considerably soften the mount system to support vibration isolating this
 main excitation force and the appearance of 3 Engines
Some . More specifically , both mount system of the engine crankshaft around
It is necessary to set to 1,000 rpm (17Hz) about the point vibration . Some examples sampling of the rubber mount in such YFZ350 and YFM400FWA in ATV , both are remembering a resonance point near 40 ~ 50Hz , it is necessary to consider the durability of the rubber mount and the displacement of the engine . There is also the torque variation is not a problem Mari Oh in the above model , I did not take into account the torque change in the basic design phase this time .
  4
Mount basic design ( non- coupled f)
On the assumption that rigid engine , basic support anti-vibration by rubber mount mosquito , √ against the frequency of forced external force , the natural frequency of the six degrees of freedom resonant system formed engine and engine mount ( center of gravity ) it is to 2 or less .
When Ru lower the supportive rigidity of the engine only because to do teeth , was Ru lower the dynamic number vibration organic solid in single , engine is so moved by driving external force and dynamic reaction force driving , engine it becomes the cause of damage to the exhaust system or contact with other parts and . Therefore , it is the support the vibration to lower the natural frequency only in the direction of an external force working force , sufficient support stiffness for the directionality of its non-
It is necessary to ensure the properties. Order to satisfy such a request , the rubber for the primary inertia couple direction of crankshaft rotation is external force forced
Soft working in shear , against the force of the vertical longitudinal direction of the drive reaction force during running , and the inclined position the mount so that the rubber becomes hard work to the compression (Figure 4 ) .
   main external force and the arrangement of Figure 4 mount
  The ATV vibration reduction by rubber engine mount of
ATV Vibration Reduction by Engine Rubber Mount System
By a mount system that is often employed , such as (FR car in particular ) car , to set properly the spring constant ratio of compression and shear of the rubber mount and tilt angle , mount rubber tilt arrangement , crankshaft speaking at this time it is possible to non- coupled vibration modes of the surrounding . The advantages to non- coupling of is as follows .
Measures when the support after performing amplitude vibration of the degree of freedom (1 ) non- coupling of becomes independent frequencies and calculation of the amplitude can be easily ( 2 ) proof , resulted in a defect easily stand
Resonance occurring against external force of degrees of freedom (3 ) non- coupling of is once
That non- coupling of the vibration due to the inclined support is able to achieve both high-dimensional most engine displacement and regulation vibration damping is required for the engine mount .
( Calculation of the natural frequency ) mount design
In order to value the aim of natural frequency to win , to achieve non- coupling of mentioned in the previous section , it is necessary to solve the following equation of motion 6 . This time , because the engine was also new design , based on the ( product of inertia ) principal axis of inertia engine center of gravity , and moment of inertia , which is obtained by calculation, mainly technical computing program ( engine mount eigenvalue calculation and steady-state response calculation) was performed calculated using .
Natural frequency of the rotation mode of the crank axis that is most important , and a 1,800 rpm aim , an intermediate idling rotational speed (1,500 rpm) in the clutch rotational speed of the CVT of (2,200 rpm).
That the surface of the support vibration isolation is set to idling speed / 1.4 as shown in the following vehicle is ideal, the motion of the engine will have significant burden on the shorter exhaust system is large compared to the vehicle or the like
 Technology
  5
 was the setting of the above with concern that it will be . Upon calculation, trial and error in the specification of the plurality ,
I select the best specification . It shows the existence mode analysis results solid Eigenvalues and production of design specifications in Table 2 . Specific mode is a vehicle standards .
Further , when applied to the crankshaft around the primary inertia couple , the steady-state response calculation result of the pitching rotation displacement amount
I is shown in Figure 5 . As shown in Fig.
Analysis results of the two eigenvalue - eigenmode Table
 natural frequency (Hz)
Primary rotational speed (rpm)
Natural vibration mode
mode 1
15.4
924
Left and right translation
mode 2
10.7
1,625
Yaw
mode 3
31.1
1,865
Pitching
mode 4
41.3
2,477
Rolling up and down translation coupled
mode 5
44.0
2,638
Before and after translation Rolling coupled
mode 6
55.97
3,358
Rolling up and down translation coupled
 resonance point has become the only , and have achieved the aim of the design .
Coupled with mode6 is seen somewhat , but I can be considered for the principal axis of inertia of the crankshaft direction of the engine is tilted 20 degrees , as shown in Figure 6 , coupling of rolling and pitching has occurred this .
This coupling is , should be solved by letting optimize the slope of the torque roll axis and an elastic main axis , but the configuration of the frame and a child that Na and complex , the pattern of a pair standing line as a production specification this specification because there may be resistance mounted engine搭Ru is poor , it is not a big coupled
Adopted .
 result of 5 pitching rotation displacement diagram
The slope of the principal axis of inertia Figure 6
  Technology
The ATV vibration reduction by rubber engine mount of
ATV Vibration Reduction by Engine Rubber Mount System
Effect of the rubber mount of
I is shown in Figure 7 vibration VGL value of YFM600FWA and YFM660FWA which adopted the rubber mount .
Comparison of 7 vibration VGL value figure
VGL value throughout the 60 or less is a development target value , for the steady-state region 55 or less , there is a part you are slightly beyond the handle , but it was almost clear .
For VGL value at high speeds , it could be a significant vibration reduction of 10dB or more is achieved , to achieve low vibration of unprecedented despite its maximum displacement ATV during a been a problem . As a result , there is a scene problems related vibration occurs in the development stage , and chased measures Until now, it was almost nil in this model.
Further , it was possible to contribute all aspects can be precision components such such as light or digital meter that was rubber mount etc. Conventional grommets are rigid all fixed , reducing vehicle weight , improved reliability , and cost reduction .
   6
  
 The ATV vibration reduction by rubber engine mount of
ATV Vibration Reduction by Engine Rubber Mount System
 Technology
  7
Challenges for the future
 is a powered rubber mounting of this time was able to raise a large effect , but is also a situation far from perfect still .
As can be seen from Figure 7 , there is a part not be fully achieved some non- coupled mosquitoes in around 3,000 rpm . In addition, the torque fluctuation in the low speed range of 660cm3 single-cylinder engine , it can be ignored as not small ones , have led to a feeling of slight deterioration can not be denied . Compatible with the displacement of the engine regulation is a major problem , but there is room for improvement for supporting the anti-vibration with respect to the torque variations.
Request level for vibration ride the market , said that every year has risen every year , further improvement of merchantability due to improvement of these parts is a challenge for future development .
Eight
With the motto KING OF INDUSTRY, set a feature of the design and many powerful four-wheel independent suspension ATV market maximum displacement engine , Yamaha Motor Co., Ltd. First , differential lock system , and innovative , YFM660FWA NEW GRIZZLY is well received since its launch has gained . Worth the name of the company create impressions in the future , I want to continue to make the ATV.
Finally , I would like to thank , thanks to the help of paper , and a call was between Ki 've had your support , your cooperation that a majority of companies inside and outside the relationship each of Ri was located in the development .
