They are all still powered by an internal combustion engine. And since the two-stroke-era is now cold in the grave, the engines are still four-stroke. They still have two wheels and a frame holding the entire works together.
So, what has changed?
Well, everything has.
The items listed above are the only similarities between the ancient Grand Prix motorcycles of the 1950's and the techno-marvels of today. The current crop of MotoGP motorcycles are a breeding ground for the future technologies that will be seen on eventual production models. That's the exact reason manufacturers race in the first place.
To illustrate the differences, let's compare two motorcycles; one from the 1950's, an AJS-7R, and the championship-winning 2008 Yamaha YZR-M1.
The AJS-7R was a 350cc motorcycle built with one thing in mind: racing.
The 7R had a duplex frame made from steel, telescopic front forks and twin rear shocks that stayed pretty much the same throughout its life-span (1948-1963). It also had the standard-issue air-cooled drum brakes and the classic squatted racing position.
The 7R's air-cooled engine went through numerous changes during its racing career. The bore and stroke started at 74x81 and was changed to 75.5x78 in 1956 by privateers. The single-cylinder engine featured an overhead camshaft with two valves for the cylinder. A special version called the AJS-7R3 with a three-valve head was built in 1951 but quickly abandoned.
Behind the engine was a four-speed gearbox.
The single pumped out 32 horsepower initially. The three-valve version offered 36 horsepower. Toward the end of the 7R's production in 1963, it was producing 40 horsepower at 7600-7800rpm and weighing in at 285lbs. Top speed was around 115-120mph.
In extreme contrast, we have the 2008 Yamaha YZR-M1.
The M1's chassis is built around an aluminum delta-box frame with fully-adjustable steering geometry, wheelbase and ride height. The front suspension consists of fully-adjustable, upside-down Ohlins forks. The rear suspension is made up of an aluminum swing-arm and a fully-adjustable Ohlins monoshock.
Providing the appropriate forward propulsion is an 800cc liquid-cooled four-cylinder engine. The valvetrain features dual overhead cams and four-valves-per-cylinder for 16 valves in total. The fuel and spark is provided by a fully-adjustable engine control unit and a fully-adjustable ignition control unit. The coolest part of the engine is the four throttle bodies, one for each cylinder.
This powerplant spits out more than 200 horsepower. Behind it is a six-speed gearbox with, you guessed it, adjustable ratios.
Tossing the anchor are twin 320mm carbon disc front brakes, each with a four-piston Brembo caliper. Out back is a 220mm steel disc with a two-piston caliper.
The M1 also has a wind-tunnel designed fairing that, when combined with the prestigious power, allows for an estimated top speed of 236mph.
236mph! On a motorcycle! Amazing.
All of this adjustability, aluminum and horsepower weighs in at 326lbs.
So what do these specs show us?
They show us that while some things have stayed the same, much of it has changed.
The AJS-7R is a pretty simple machine. It is, for all intents and purposes, a beefed up street model. Aside from the engine, nothing on it is exotic in any way. Telescopic forks and twin rear shocks were pretty commonplace during its production life. The frame is also a ho-hum steel frame, similar to 99% of the street motorcycles produced at the time.
The engine really isn't that exotic either. Overhead cam aside, it's still an air-cooled single-cylinder. The AJS-7R really isn't very much removed from a regular, production motorcycle.
The M1 is a two-wheeled spacecraft in comparison.
Almost everything is adjustable and the frame is of lightweight aluminum specifically designed for the bike. Even the wheels are trick, with them being 16.5 inches front and rear and being made out of carbon fiber.
Add in the extreme horsepower and the insane top speed and you have an exotic piece.
The speed, lightweight materials and adjustability of the YZR-M1 make the AJS-7R look like an ox-cart. Aside from them both being motorcycles, they have nothing in common.
MotoGP bikes will continue to push the envelope because that is what they do. For example, Ducati has used a carbon fiber frame for the past few seasons.
The motorcycle's concept hasn't changed much in the past 100 years but the execution changes at a hurried pace.
A 1959 AJS-7R shows what a race bike used to look like. Pretty simple looking, isn't it?
The 2008 Yamaha YZR-M1 illustrates the future of the race bike. That seat looks really comfortable...
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