In 2009, Italian motorcycle manufacturer Aprilia introduced the MXV 450, a motocross bike that uses the same compact V-twin engine as the Aprilia SXV and RXV. Most 2009 motocross bikes are single-cylinder, so Aprilia went to some lengths to achieve the same light weight found in a single-cylinder engine, shaving ounces off the bike’s total poundage in a number of ways.
The 449cc, liquid-cooled, four-stroke V-twin engine is placed at a 77-degree angle, just as it is in Aprilia’s racing bikes, and acts as a stressed member of the aluminum and steel frame. The single overhead cam uses titanium valves, the crankcase is an aluminum alloy, and, in another move designed to keep the weight down, the bike has a kick starter rather than an electric starter, which eliminates the need for a starter battery. The transmission, a four-speed manual with motocross gear ratios, works with a multi-plate wet clutch and a chain final drive.
The engine firing has two settings, known as the Big Bang and the Screamer. The Big Bang is designed to maximize power delivery by closing the firing gap between the cylinders. The Screamer setting reverts to the standard firing gap for a 77-degree V-twin engine. This is a modern machine: a rider downloads the programmable settings to his computer and transfers them to the bike. The electronic fuel management system integrates the fuel injection with the firing pattern, letting riders switch between a full-power mapping and a soft mapping for difficult conditions.
A Marzocchi inverted fork with adjustable preload and rebound damping and a Sachs twin-sided swing arm, also with rebound damping and an adjustable spring preload shock, provide suspension that every rider can tailor to his or her needs. Stopping power comes from Nissin hydraulic disc brakes in the front and rear.
The bike’s styling is slim – its total width is just 32.1 inches – and its wheelbase is a compact 59 inches. Fork guards, heel guards, and chain and exhaust guards are all standard, as are hand grips. The Aprilia MXV is a business-like machine, and its business is all off-road. It is not street legal – it has no headlights, no turn signals, and no instrumentation of any sort.