Forged Piston

The Yamaha R15 has incorporated many advanced technologies. And now, I would like to throw light on some of these. I would like to start with Forged Pistons.
Talking with a Yamaha engineer, he revealed, "The most common type of piston used on automobile and motorcycle engines are cast aluminium pistons. It is said that most of the motorcycles in India have cast aluminium pistons. Casting is done by melting aluminium at high temperatures and puring the molten aluminium into a mould. The cast aluminium piston is commonly used because of its strength, good heat dissipation rate, light weight and ease of manufacture. Despite the high reliability and proven performance of cast piston, we chose to go for the next higher level of performance and a better ride by developing a technology for mass producing quality forged pistons.
The aluminium forged piston is made by heating the aluminium alloy to a temperature lower than the melting point and pressing (forging) it into a mould. because the aluminium is not actually melted, there is much less effect on the original mettalurgical matrix and therefore the aluminium loses little of its original strength. Due to this increased strength, the forged piston can be made thinner and lighter. This fact also means that the forged piston has a lower reciprocating mass when the engine is running. Ofcourse this also helps reduce the overall weight of the machne. The forged piston is a feature on many luxury cars and on race machines"
Phew, that is some technology! Asking the engineers, why they used such a high tech thing on R15, they said, "In fact the very strength of the aluminium alloy used in forged pistons makes it hard to manufacture. Also, while forging a complex shaped part like a piston, optimising the amount of pressure with which the aluminium alloy is forged into the mould and the temperature of the mould is difficult. The aluminium alloy used for forging has a very narrow temperature range where it is easily forged. That is why it is difficult to makepracticle use of forged pistons in mass production. To solve this problem, we developed an exclusive manufacturing system utilising a 'controlled forging technology'. In this system, the alluminium alloy and the mould are both heated exactly to the optimum temperature and the forging pressure is also optimised. This made it possible to mass produce high quality forged pistons. And these pistons are now being used on the YZF-R and MT-01 sports models made in Japan. And now, in order to achieve the development goals of the YZF-R15, we have set up a forged piston production system in India."
Now that definitely means that Yamaha is keen on getting its international technology in India. For now, thats all. More on forged pistons soon!
Till then, ride safe!
(Source : Bike India)