Yamaha is not satisfied with simply providing reliability that gives assurance, because reliability that adds to the excitement of the ride fits snowmobiles better.
Dependable Yamaha engines
The engines of Yamaha snowmobiles are built with a base of highly reliable parts and components. The forged aluminum pistons are formed without melting the original aluminum stock, so they retain the strength of the original solidification structure, which enables the design of a lighter piston. This lightweight piston contributes to better pick-up while also reducing vibration. Furthermore, the fuel injection system provides surer starting and improved power development as well as other benefits. For example, the fuel is injected in a way that makes possible more uniform combustion, which in turn means less wasted motion by the piston (wobble) and contributes to reduced mechanical noise as a result.
The direct-plated cylinder adopted from the first RX-1 model is a feature that not only provides high performance but also improves reliability and contributes to reduced oil consumption. The plated cylinder eliminates the need for a steel cylinder sleeve with its lower heat transfer rate, which improves heat dissipation around the combustion chamber. This alleviates the heat stress on the oil and thus slows the deterioration of performance and contributes to lessened oil consumption.
Yamaha Motor has been aggressively developing aluminum forging and casting technology since the 1960s and fuel injection technology since the 1970s, and these state-of-the-art Yamaha technologies have been applied in optimum ways in our snowmobile engine development. That is why they offer reliability in snowmobile use that can't be duplicated by snowmobiles that use multipurpose engines or adapted motorcycles engines.
A focus on evaluation that supports Yamaha reliability
The reliability Yamaha Motor provides has a particularly strong focus on durability. No matter what high levels of performance may be achieved in the engine, frame and suspensions, they are all meaningless if they don't continue to function properly.
For example, the suspension is an important component in determining the quality of the snowmobile's ride in its role of maintaining positive contact with the snow surface. At the same time, it has the role of absorbing shocks from the snow surface to protect the rider and the machine and ensure the comfort and enjoyment of the ride. Despite having these diverse roles, it is also a sensitive device that is vulnerably exposed to outside forces and composed of numerous interrelated precision parts that leave no room for flaw.
For these reasons, development of a quality suspension involves many steps. Those steps begin with developing the unit strength based on evaluations of performance in summer and continue into tests under different conditions on fresh snow, in deep snow and on icy surfaces in North America, Europe and Japan. In these ways Yamaha Motor works to reach higher levels of durability and reliability in its product development.
Excitement enabled by the feeling of stability
Yamaha 4-stroke snowmobiles have an inherently high feeling of stability in their performance as machines. The reason is that unlike 2-strokes that add engine lubricating oil to the fuel, 4-strokes have completely separate fuel supply and lubrication systems. Furthermore, because the intake and exhaust valves are also set separately, there is less loss due to blow-back (blow-by) and, thus, better fuel efficiency can be maintained. The direct-plated cylinder also has plating applied directly to the cylinder wall to eliminate the need for a steel cylinder sleeve and in doing so ensures excellent abrasion resistance and cooling performance. In addition, since the piston and cylinder are both aluminum with the same thermal expansion rate, there is less variance in contact surfaces, so there is less wasted piston motion and, as a result, more stable combustion performance.
The aluminum parts used in Yamaha products are known for their slow rate of deterioration. This is not simply because they are made of aluminum. Take our aluminum frames for example. They are actually hybrid frames made from an assortment of parts made of different methods including forging, gravitational, low pressure or high-pressure casting and Yamaha Motor's exclusive CF aluminum die casting method. These methods enable the production of aluminum parts with different qualities to meet the differing demands for strength, rigidity and elasticity where required in the different parts of the chassis. Building a structure that is highly durable with regard to external forces with this array of function-specific parts helps slow deterioration over time and thus ensures that the machine continues to provide stable, high-level performance.
And it is not just the material qualities of the parts that prevent deterioration. Yamaha pursues stability in performance from a number of perspectives, including processing and finishing methods and structural and compositional aspects. The result is snowmobiles that bring the owner more riding excitement over a longer product life.