Yamaha XV1900A
Encyclopedia
The Yamaha XV1900A is a motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

 manufactured by the Yamaha Motor Company
Yamaha Motor Company
, is a Japanese motorized vehicle-producing company. Yamaha Motor is part of Yamaha Corporation and its headquarter is located in Iwata, Shizuoka. Along with expanding Yamaha Corporation into the world's biggest piano maker, then Yamaha CEO Genichi Kawakami took Yamaha into the field of motorized...

 and sold in the United States through Yamaha's Star Motorcycles
Star Motorcycles
Star Motorcycles is a US-specific brand of cruiser motorcycles. It is a wholly owned subsidiary of Yamaha Motor Company and is used on Yamaha's current cruiser motorcycles.-History:...

 division. It is the largest Yamaha V-twin motorcycle in production.

Development

The Yamaha XV1900A cruiser was developed to exploit the high capacity end of the market for large cruisers
Cruiser (motorcycle)
Cruiser is the term for motorcycles that mimic the design style of American machines from the 1930s to the early 1960s, including those made by Harley-Davidson, Indian, Excelsior and Henderson. The market for models evocative of the early cruisers has grown to embrace 60 percent of the U.S...

. Yamaha had a well established range of big "Star" cruisers which went up to the Yamaha Wild Star 1600 cc
Yamaha XV1600A
The Yamaha XV1600A is a cruiser style motorcycle. It is also called the Yamaha Road Star or in Europe the Yamaha Wild Star. It has been produced from 1999 through current model Year 2012. The 1999-2003 models were the same 1602cc naturally aspirated engines. And in 2004 they changed the...

 but there was a need to redesign the engine to meet anticipated exhaust emissions regulations and the opportunity to update the styling, which had remained largely unchanged for a decade.

Engine

The 1854 cc four-stroke air-cooled V-twin
V-twin
A V-twin engine is a two-cylinder internal combustion engine where the cylinders are arranged in a V configuration.- Crankshaft configuration :Most V-twin engines have a single crankpin, which is shared by both connecting rods...

 engine was purpose built to deliver maximum torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

 at 2,500 rpm in the 55 mile per hour range used for motorcycle cruising. Set at 48 degrees, the cylinders have a four pushrod valves, twin spark plug cylinder heads, with 100 mm (3.9 in) diameter plated forged pistons.

With a 100 mm (3.9 in) bore and a stroke of 118 mm (4.6 in), the engine has a compression ratio of 9.5:1 and is the first Yamaha cruiser motorcycle to be equipped with the compact Exhaust Ultimate Power Valve (EXUP) 4-stroke power valve system
4-stroke power valve system
A Four-stroke power valve is a device fitted to four-stroke engines that constantly adjusts the internal diameter of the exhaust system to better suit engine speed. At low engine speeds the wave pressure within the pipe network is low...

 previously only found on their range of high performance sports motorcycles.

An unusual feature of the new engine is a special 'pent roof' combustion chamber, designed to increase the efficiency of gas flow. The engine also has special balancers on both sides to reduce the vibration typical of large V-Twins.

Transmission

The engine’s output is transmitted via a wide-ratio five-speed gearbox and compact new transfer case, with power delivery controlled by a hydraulic clutch featuring a four-step adjustable lever. For quiet operation together with low maintenance requirements, the Midnight Star is equipped with a belt drive system.

Frame

A lightweight long wheelbase (1715 mm (67.5 in)) frame was designed using aluminium die casting
Die casting
Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process...

to minimise weight, with a double cradle design to provide the strength. Suspension consists of a die cast aluminium swinging arm and a hidden single horizontal rear shock absorber and large diameter front forks.

Raider version

In 2010, a custom version was produced in limited numbers featuring a lowered seat, lengthened front forks, a wider 210 mm rear tyre, the widest on any Yamaha motorcycle,
and special black finish to the engine and a range of custom fittings.

External links

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