I have been a biker for more than 30 years but I never really fancied Moto Guzzi bikes that, however, have a small number of very keen followers ans supporters. As I live nearly next door to a motorbike dealer it happens quite often that I walk past their shop and I quickly stop to have a look at the models in display. The other day I was having my usual look and my eye caught these two words (see picture) on the head of one the two cylinders on this brand new Moto Guzzi. Quattro Valvole means four valves (per cylinder) and it is a fairly common configuration for many petrol engines in the 21st century, being them inside a car or mounted on a motorbike. In fact I remember when, in the early eighties, most Japanese manufacturers started to introduce engines with four valves per cylinder. By the mid eighties Yamaha even introduced the 5 valves per cylinder; that’s around 30 years ago, and even then not many of these precursors of the four (or five) valves made too much noise about the whole thing.
Having more than two valves in each cylinder introduces extra manufacturing costs to the engine as well as extra complexity. At the same time it offers several advantages: the gases inside the cylinder flow better and faster improving the engine efficiency; also time several valves will be individually smaller than two big ones reducing inertias and allowing the engine running at higher revs.
Starting from the eighties, car manufactures spent their marketing budgets for quite some time to add the four valves feature either within the name of new models or by splashing it in their literature and adverts. Four valves engines were initially installed on sport cars and high performance models but gradually economy of scale justified their usage even for the lower end of the market. Collectively manufacturers spent real fortunes to educate us all about the fact that four valves were very much a benefit that everybody should aim at. As it happened to fashions fading away any reference to four (or any number of) valves gradually disappeared altogether and while we are driving today vehicles having very sophisticated engines full of electronic devices and controllers that make them very reliable and efficient many of us probably are not aware of how many valves are in the engine of the car we drive.
For that reason I was very surprised when Moto Guzzi decided not just to build an engine with four valves per cylinder but decided, in 2013, to let everybody know about this but writing it straight onto the engine itself. Did their designers and marketers spent the last 30 years cryogenically frozen?