YAMAHA XV1900 MIDNIGHT STAR
XV1900 Midnight Star
The New Cruiser Experience
For the 2006 season Yamaha will launch the all-new Yamaha XV1900 Midnight Star cruiser. Powered by the largest Yamaha V-twin to date, this advanced new motorcycle combines advanced technology with timeless style. Driven by a high-torque 1854cc air-cooled V-twin engine, running in a long-and-low high-tech aluminium chassis, and with radical Neo-Streamline bodywork with superb finishing, the Yamaha XV1900 Midnight Star has become one of the jewels in the cruiser class.
Among certain riders there is a trend to look at alternative cruisers that offer more advanced technology, higher engine and chassis performance and more radical and high-class styling.
The Midnight Star design team set out to achieve four main goals:
1 To create a new-generation large capacity V-twin with a sensual and exciting power pulse feeling that would exceed the expectations of customers.
2 To build a machine with such a beautiful and intricate ‘jewellery value’ exterior design that riders would only need to see it once to know that it was their kind of bike.
3 To achieve the strongest low to mid-range torque, and to deliver the best power delivery characteristics in the 55mph-75mph (90-120kph) zone.
4 To exceed existing and imminent emissions regulations.
All-new 1854cc (113 cubic inch) 4-stroke V-twin air-cooled OHV engine.The Midnight Star is the new flagship in Yamaha’s Star line-up, and accordingly, this remarkable new cruiser’s massive air-cooled engine has been developed to deliver class-leading levels of power and torque.
In order to achieve a whole new power cruising experience for exciting cross-country riding, Yamaha have introduced sophisticated new technology to the classic large-capacity V-twin configuration.
Displacing 1854cc (113 cubic inches), the 48 degree V-twin air-cooled OHV 4-stroke engine benefits from a highly advanced specification that includes 4-valve twin-spark plug cylinder heads, forged pistons, pent roof combustion chambers, EXUP, oil cooling, fuel injection, 100mm diameter plated cylinders and a hydraulic clutch.
In order to achieve the high levels of deep torque and direct power feel that today’s large-capacity cruiser riders demand, the 100 x 118mm bore x stroke engine runs with a high compression ratio of 9.5:1, and is equipped with a compact EXUP system that substantially boosts low to mid-speed pulling power.
Furthermore, this advanced new air-cooled V-twin is equipped with a newly designed separate left/right balancer system that reduces vibration without diluting the engine’s mighty power pulses – and these feel-good vibes are accentuated by the Midnight Star engine’s optimised flywheel mass and damper-less crank.
Delivering maximum torque at 2500rpm, and generating thunderous power pulses together with a direct power feeling, the Midnight Star engine offers new riding sensations. This radical new cruiser delivers truly sensual performance and higher levels of excitement that are felt instantly by its rider.
Separate left/right side balancers
The newly designed separate left/right side balancer systems featured on the Midnight Star offer a number of benefits over the traditional balancer design. Typically, a conventional balancer system often consists of dual shafts that take up a lot of crankcase space and add to the engine’s overall weight.
However, the Midnight Star engine employs two separate balancer mechanisms positioned on either side of the crankshaft. The left side weight is on the same axis as the crankshaft, while the right side weight is positioned close to the crankshaft. This innovative balancer system minimises uncomfortable vibrations while allowing the feel-good power pulses to be transmitted, and the compact layout has enabled Yamaha’s designers to keep the crankcase size relatively compact for such a large capacity engine.
High compression 4-valve twin-spark cylinder heads and forged pistons.
One of the most important features of the new 1854cc engine is its feeling of direct and instant power, and the design of the cylinder heads and pistons play a major role in achieving this goal. The two spark plugs per cylinder design ensures instantaneous combustion, while the 4-valve high compression head and pent roof combustion chamber make for high levels of gas ?ow efficiency. In addition, the optimised cam profiles and lightweight 100mm diameter short-skirt forged pistons further contribute to the engine’s sensual and responsive performance characteristics.
Optimised flywheel mass
Yamaha’s engineers have selected a flywheel with an optimal mass, and this feature, together with a damper-less crank design, accentuates the Midnight Star’s feeling of direct power delivery. Another crucial factor in determining driveability is the relationship between torque output, gear ratios and tyre diameter. On the Midnight Star these ratios are idealised so that when running in top gear, the machine’s crankshaft turns 3.14 times for each revolution of the rear wheel – a ratio which equates to 3,300rpm at 75mph (120kph).
Compact air cleaner box
Feeding the huge 1854cc engine is a compact and highly efficient 3.5 litre air cleaner box which features separate front and rear ducts. This newly designed airbox creates a strong pulse effect to boost intake efficiency, while at the same time taking up less space than other systems. This compact design does away with the need for a side-mounted air cleaner, which makes the engine’s right side V cylinders more visible than on many other cruisers.
Downdraft type fuel injection system
A newly designed 12-hole fuel injection system equipped with large diameter throttle bodies delivers the fuel/air mix via large 36mm diameter intake valves into the pent roof combustion chamber. Burnt gases exit the highly-efficient 4-valve cylinder head via 31mm diameter exhaust valves before passing through stainless header pipes which merge into one. This efficient fuel injection system is equipped with an Idle Speed Control (ISC) for stable idling performance, and a self-diagnostic function of the fuel injection system ensures consistent performance.
Compact EXUP system and 2-into-1 muffler
Another important technological feature that makes a signi?cant contribution to the huge levels of low to mid-range thrust is the EXUP system, and the Midnight Star is the first Yamaha cruiser to be ?tted with this advanced exhaust powervalve. More usually associated with Yamaha’s sport bikes, the EXUP is a variable valve that constantly alters the exhaust’s cross-sectional diameter to match the engine’s running speed. By ‘tuning’ the exhaust to suit prevailing conditions, the EXUP valve prevents exhaust blow back during the 75 degree valve overlap period, and this ensures high levels of torque, notably in the 2500-3000rpm range.
The compact EXUP is situated at the point where the two large-bore exhausts merge into one, and the whole exhaust system – including length, diameter and volume – has been developed in conjunction with the intake system including the airbox. By developing the intake and exhaust systems as a whole, a harmony has been achieved between the two, resulting in a gutsy and satisfying engine tone.
3-way catalytic converter with oxygen sensor.
As well as being the first Yamaha cruiser to be equipped with EXUP, the Midnight Star is also the first Yamaha in its class to feature a 3-way catalytic converter with an oxygen sensor. Manufactured from platinum and rhodium embedded in a stainless steel honeycomb, the catalyser is situated in the silencer’s first expansion chamber, while the oxygen sensor is located between the EXUP valve and silencer. Data on oxygen levels is fed to the ECU, which then adjusts the fuel injection system to ensure the effective operation of the catalyser, and in doing so ensures the efficient and environmentally-friendly performance of the Midnight Star.
Pinpoint oil cooling system
The pinpoint oil cooling system featured on the Midnight Star is another ‘first’ for a Yamaha cruiser, and is designed to ensure stable performance from this high compression, high torque air-cooled engine. Engine oil is circulated through the 4-valve twin-spark plug cylinder head, and oil is also pumped out directly behind the piston for increased cooling efficiency.
Oil temperature is moderated by an oil cooler – another ‘first’ for a Yamaha cruiser – and the crankcase and transmission compartments are separated by a wall, and each compartment has its own 3-blade oil pump to ensure optimum oil circulation. With its separate oil pumps for the crankcase and transmission and an oil cooler, this high performance air-cooled V-twin engine is designed to deliver consistently high levels of power output in all conditions.
High quality engine exterior finish
While the inside of the new Midnight Star engine is an example of Yamaha’s advanced engineering at its very best, the exterior styling and finish also set new standards for a large-capacity V-twin.
By using the latest casting technology, Yamaha’s engineers have been able to create beautifully styled cylinders with extra-large cooling fins featuring very few vertical ribs. Each cylinder head features seven fins, while the cylinders have thirteen each, all of them spaced at 10mm, and each of the fins is specially treated, giving a sparkling ‘jewellery’ effect as sunlight reflects off the engine.
The appearance of the front cylinder is enhanced by the positioning of the starter motor close to its base, and by tapering the chrome-plated push rod covers, the visual impact of the huge V-twin engine is heightened. Finally, as a finishing touch, the aluminium clutch and head covers are manually buffed to underline this big V-twin’s individual character and high quality ‘jewellery’ finish.
Compact decompressor system
The force required to start such a large-capacity high-compression engine is enormous, and so a compact new mechanical decompression system has been developed for the Midnight Star. The new exhaust camshaft features a centrifugally operated decompression mechanism, and this compact design eliminates the need for a bulkier electric solenoid system, and in doing so, saves space and weight.
Hydraulic clutch and belt drive
The engine’s massive torque output is transmitted via a wide-ratio 5-speed gearbox and compact new transfer case, with power delivery controlled by a hydraulic clutch featuring a 4-step adjustable lever – and for smooth, quiet operation together with low maintenance requirements, the Midnight Star is equipped with a clean-running belt drive system.
Outstanding performance, unrivalled character
By combining the most advanced engineering solutions with a classic air-cooled OHV design, Yamaha have created a class-leading engine that delivers sensual and exciting performance combined with the depth of character that only a large-capacity V-twin can deliver. In addition to its undoubted technical prowess, this ground-breaking powerplant also benefits from unrivalled attention to its external appearance, and an exquisite ‘jewellery’ style finish.
This is one engine that is truly in a class of its own.
ENGINE TECHNICAL HIGHLIGHTS
? All-new 1854cc (113 cubic inch) 48 degree V-twin air-cooled OHV
? Bore x stroke 100 x 118mm
? 4-valve twin-spark plug cylinder heads
? High 9.5:1 compression ratio
? Pent roof combustion chambers
? Fuel injection
? Forged pistons
? Separate left/right dual balancer
? 2-into-1 muffler with EXUP
? 3-way catalytic converter with oxygen sensor
? Oil cooler
? Optimised crank mass
? Damper-less crank
? Mechanical decompressor system
? Hydraulic clutch
? Belt drive
Midnight Star Chassis
Timeless style. Futuristic technology.
The theme of timeless style fused with futuristic technology continues with the advanced new chassis and bodywork. While following the proven ‘long-and-low’ formula pioneered by Yamaha’s Star models, this high-tech aluminium chassis and streamline bodywork is every bit as special and unique as the new engine.
Lightweight long-wheelbase aluminium frame
The 1715mm long-wheelbase chassis design incorporates a highly rigid all-aluminium double-cradle frame that is significantly lighter than the conventional steel frames used by many other cruisers.
Consisting of just eight components, this new frame has been manufactured using Yamaha’s exclusive aluminium die-casting technology which makes it possible, for the first time on a cruiser, to create a frame with walls of varying thickness for the optimal strength/rigidity balance.
Widely-spaced upper and lower rails give an extremely strong structure for sure-footed handling performance. Stability and handling performance is also enhanced by mounting the V-twin rigidly to the chassis, and this feature also has the added benefit of allowing the rider to feel directly the sensual character of the engine’s power pulses.
Dynamic new CF die-cast tapered aluminium swingarm
Also new is the CF die-cast aluminium swingarm, which is manufactured using Yamaha’s patented CF die-casting technology, a system that has opened up new possibilities in aluminium chassis design. In short, this technology enables the manufacture of complex, thin structures that maintain their strength and rigidity while saving weight.
Consisting of three parts that are welded together, the lightweight swingarm tapers down from the pivot point to the pointed tips, giving the Midnight Star’s chassis a unique and futuristic new look which perfectly complements the timeless streamline bodywork.
In addition to keeping overall weight down, the cast aluminium swingarm keeps unsprung weight low, thereby improving rear suspension characteristics and giving a higher quality ride, solo and two-up.
Idealised front/rear weight distribution and optimised dimensions
The new Midnight Star is unique in the cruiser category in that it has a idealised front/rear weight distribution of 49.6/50.4, which is comparable to that of a sports bike, and quite different to that of other cruisers, which would typically be 45/55. This idealised front/rear weight distribution, together with the frame’s strength/rigidity balance and caster and trail dimensions make for a natural handling feeling that perfectly complements the machine’s sensual and exciting power characteristics.
Large diameter front forks
In the best cruiser tradition, the large diameter 46mm inner tube front forks are equipped with fat tapered steel fork covers – and for the finishing touch, these tube covers feature a slant cut lower edge, underlining the close attention to detail that characterises this new-age cruiser. The fat fork covers complement the large headlamp and teardrop fuel tank, and accentuate the ‘big boned’ look of this large capacity cruiser.
Concealed rear shock
The single rear shock is hidden behind the machine’s bodywork, giving an attractive ‘clutter-free’ streamline rear end when compared to some other twin-shock cruisers. The compact, horizontally-mounted shock also helps to keep the machine’s centre of gravity low – and largely because of the bike’s low unsprung weight, the plush rear suspension action is going to be a revelation for many cruiser riders.
12-spoke alloy wheels
The newly designed cast alloy wheels feature a 12-spoke design that give an impression of being extra thick wire spokes, which underlines this sophisticated cruiser’s very special blend of character, technology and style. To ensure smooth transmission of power while maintaining the desired direct power delivery feeling, the rear wheel uses iron rubber dampers.
The 17 inch rear wheel runs with an extra-wide 190/60-17 radial, while the 18 inch front is equipped with a 130/70-18 – a combination that gives strong roadholding combined with high levels of rider and passenger comfort.
High-specification front brakes
This cruiser’s braking specification is one of the highest in the category, and features dual 298mm diameter front discs gripped by powerful 4-piston monobloc calipers, for responsive and controllable stopping power. This powerful front system is complemented by a large diameter 320mm rear disc and underslung caliper which gives plenty of feedback for optimum controllability.
Wide and fat pull-back handlebars, together with the low seat height and long footboards make for a comfortable riding position – and for added convenience the rocker-style shift pedal has individually-adjustable front and rear sections.
To emphasis the bike’s stylish and simple lines, the wiring harness runs inside the handlebars. A hydraulic clutch ensures effortless gear changing, and features a 4-step span adjuster, while a new uni?ed front brake lever and master cylinder assembly once again shows the high levels of attention to detail that are evident on this new generation cruiser.
Lighting and instruments
At the front end the XV1900 Midnight Star is equipped with a powerful double headlight housed within a 1950’s-style nacelle, while the lightweight triangular tail light incorporates twelve LEDs.
The high quality instrumentation is tank-mounted, and features a centrally-mounted clock-type analogue speedometer, with a tachometer to the lower left and a fuel gauge to the lower right, as well as a multi-function digital display. At night the digits are lit in blue against a soft white background, emphasising the high levels of quality and style that are evident throughout this flagship cruiser.
Neo-Streamline cruiser bodywork
Virtually every component on this new cruiser has been designed to appear as if it is flowing with the wind, whether it’s the flared fenders, teardrop fuel tank, swept-back handlebar holders or the pointed swingarm. This Neo-Streamline look is an expression of a smooth speed form, combined with the imagery of power thrusting forward.
In addition to the individual components that fuse together to create the Midnight Star’s unique Neo-Streamline look, the extra-long 1715mm wheelbase aluminium frame allows the massive V-twin engine to be located well ahead of the machine’s mid-point. All of these elements interact to create a distinctive ‘mass-forward’ form, in contrast to the rearwards mass bias of some other cruisers.
The rider also plays a role in the mass-forward form, and the combination of low, wide handlebars, a low seat and forward-mounted footboards accentuate the front end mass bias.
The Midnight Star’s bodywork combines elements of elegance with power, speed and beauty, to give Yamaha’s new flagship cruiser the most distinctive profile on the street.
? Class-leading all-aluminium double cradle frame
? CF die-cast aluminium swingarm
? Extra-long 1715mm wheelbase
? Low 735mm seat height
? 46mm inner-tube front forks with tapered, slant-cut outer cover
? Pre-load adjustable rear suspension with link system and hidden
? ‘Mass-forward’ appearance
? Original ‘Neo-Streamline’ styling
? Deeply valanced ?ared fenders
? External aluminium rear fender stays
? Massive double headlight with retro-style nacelle
? Triangular LED tail light
? Classic tank-mounted instrumentation
? Wide and low 17-litre teardrop fuel tank
? Long forward-mounted foot boards
? Fat low-rise pull-back handlebars
? Wiring harness inside handlebars
? Plated upper triple clamp cover
? Dual 298mm front discs with high-specification 4-piston calipers
? Large diameter 320mm rear disc
? New 12-spoke cast alloy wheels
? 190/60-17 rear radial tyre
? 130/70-18 front radial tyre
Yamaha Midnight Star. The retro-futuristic cruiser.
By taking the very best in timeless styling and blending it with advanced 21st century engine and chassis technology, Yamaha have created an individual large-capacity V-twin cruiser that offers high class, combined with performance and character.
Designed to appeal to discerning cruiser riders who are looking for technical excellence, superb quality and a distinctive new look, the Yamaha Midnight Star represents a unique fusion of the past, present and future.