The Yamaha RD500LC is a high-performance,

two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a Thermodynamic power cycle, power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being comple ...

sports Sport pertains to any form of competitive physical activity or game that aims to use, maintain, or improve physical ability and skills while providing enjoyment to participants and, in some cases, entertainment to spectators. Sports can, th ...

motorcycle A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...

, also known as the RZ500 in Canada and Australia. A lightened but detuned version known as the RZV500R was developed for the Japanese home market. Strict

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

regulations meant that the RZ500 was not available for sale in that country. Produced for a short period between 1984 and 1986 it has become a sought after collector's machine.Motorcycle.com

Development

With the success in the early 1980s of

Kenny Roberts Kenneth Leroy Roberts (born December 31, 1951, in Modesto, California) is an American former professional motorcycle racer and racing team owner. In 1978, he became the first American to win a Grand Prix motorcycle racing world championship. He ...

and the

Yamaha YZR500 The Yamaha YZR500 was a for 500cc Grand Prix motorcycle racing, Grand Prix racing motorcycle made by Yamaha Motor Corporation, Yamaha from 1973 through 2002. Racing history The YZR500 was ridden by championship winners Giacomo Agostini (1975 G ...

Grand Prix motorcycle racing Grand Prix motorcycle racing is the premier class of motorcycle road racing events held on road circuits sanctioned by the Fédération Internationale de Motocyclisme (FIM). Independent motorcycle racing events have been held since the start ...

Yamaha realised that a road going replica of their 500 cc racing machine would sell well. Using the similar technology of the smaller RD series of two-stroke motorcycles the RD500LC was launched in 1984.

Design

Engine

The RD500LC (Race Developed 500CC Liquid Cooled motorcycle) uses a 50-degree, twin-

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

V4 engine A V4 engine is a four-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration. The V4 engine is less common compared to straight-four engines. However, V4 engines have been used in automobiles ...

layout. Linked Yamaha

YPVS {{Unreferenced, date=February 2018 The two-stroke power valve system is an improvement to a conventional two-stroke engine that gives a high power output over a wider RPM range. Operation of a two-stroke engine A '' stroke'' is the action of a p ...

exhaust power valves are controlled by a single electronic unit and

servo motor A servomotor (or servo motor) is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also r ...

and are designed to give a broader

power band The power band of an internal combustion engine or electric motor is the range of operating speeds under which the engine or motor is able to output the most power, that is, the maximum energy per unit of time. This usually means that maximum a ...

. The engine also features intake

reed valve Reed valves are a type of check valve which restrict the flow of fluids to a single direction, opening and closing under changing pressure on each face. Modern versions often consist of flexible metal or composite materials (fiberglass or carbon f ...

s unlike the YZR500 racer which used rotary disc valve induction. The reed valves use two different intake arrangements, the lower

cylinders A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infini ...

are fed through

crankcase In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...

mounted reeds; the upper pair use cylinder barrel mounted reeds. The four Mikuni

carburettors A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meterin ...

are side mounted in pairs and feed each cylinder through 90 degree intake

manifold In mathematics, a manifold is a topological space that locally resembles Euclidean space near each point. More precisely, an n-dimensional manifold, or ''n-manifold'' for short, is a topological space with the property that each point has a n ...

. The lower

expansion chamber On a two-stroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency. History Expansion chambers were invented and successfully manufactured by Limbach, a ...

s exit normally but the upper pipes cross over each other just behind the exhaust ports to maintain the correct tuned length. The dual crankshafts are geared directly to the

clutch A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...

, while the front crankshaft also drives a counter balancer shaft mounted between the two crankshafts. The counterbalance shaft, unusual on a two-stroke, assists with damping engine vibrations. The engine is cooled by

thermostat A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint. Thermostats are used in any device or system tha ...

ically controlled

liquid cooling Liquid cooling refers to cooling by means of the convection or circulation of a liquid. Examples of liquid cooling technologies include: * Cooling by convection or circulation of coolant, including water cooling * Liquid cooling and ventilatio ...

, an auxiliary electric fan mounted behind the

radiator Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

cuts in at quite high but acceptable working temperatures (e.g. when stationary in traffic).

Lubrication Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubric ...

is by direct injection into the inlet manifolds using Yamaha's 'Autolube' pump system. Normally controlled in other two-stroke engines by

throttle A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...

position, the engine oil pump is controlled by the YPVS servo motor ensuring that the oil supply is not shut off at high engine

revolutions In political science, a revolution (Latin: ''revolutio'', "a turn around") is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolts against the government, typically due ...

.Yamaha Service manual

Transmission

The RD500LC uses a six-speed sequential close ratio gearbox with the usual road-going 'one down and five up' sequence, the gear shafts are removable from the right side of the engine without the need to split the crankcases. The clutch is of the wet, multiple-disc coil spring type and is cable operated. Unusually for a two-stroke engine the gears and outer crankshaft bearings are lubricated by a separate crankshaft driven

trochoid In geometry, a trochoid () is a roulette curve formed by a circle rolling along a line. It is the curve traced out by a point fixed to a circle (where the point may be on, inside, or outside the circle) as it rolls along a straight line. If the ...

oil pump. Final drive is by conventional for the time

O-ring chain {{Refimprove, date=September 2008 The o-ring chain is a specialized type of roller chain used in the transmission of mechanical power from one sprocket to another. Construction The o-ring chain is named for the rubber o-rings built into the sp ...

and

sprocket A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passi ...

Chassis

The

frame A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...

of the RD500LC is manufactured from

mild steel Carbon steel is a steel with carbon content from about 0.05 up to 2.1 percent by weight. The definition of carbon steel from the American Iron and Steel Institute (AISI) states: * no minimum content is specified or required for chromium, cobalt ...

box-section and uses a perimeter layout. The rear

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...

is unusually placed horizontally under the engine and uses the lower crankcase as a mounting point. The under-seat area is occupied by the upper cylinder exhaust chambers, the oil pump and one-way valves, the battery and the YPVS (Yamaha Power Valve System) servo motor. The battery is of the 'wet' lead acid type and a cut-out is provided in the right side panel to view the acid levels without having to dismantle half the bike! The rear of the shock absorber connects to an

extruded Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

aluminium alloy An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal ...

swinging arm A swingarm, or "swinging arm" (UK), originally known as a swing fork or pivoted fork, is a single or double sided mechanical device which attaches the rear wheel of a motorcycle to its body, allowing it to pivot vertically. The main component of ...

via several forged aluminium rocker arms. An unusually small

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for ...

16-inch wheel is held between spring and oil damped

forks In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods ei ...

which featured adjustable anti-dive units. The RD500LC uses twin ventilated

disc brake A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a "rotor" to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hol ...

s for the front wheel with a single ventilated disc at the rear. A solo seat cowl was originally provided to cover the

pillion A pillion is a secondary pad, cushion, or seat behind the main seat or saddle on a horse, motorcycle, bicycle or moped. A passenger in this seat is said to "ride pillion". The word is derived from the Scottish Gaelic for "little rug", ''pillean' ...

seat when not in use. The Japanese market RZV500R differs from the RD500 by ''not'' having a rear-mounted pillion grab handle fitted (which gives a cleaner, more race-oriented look to the motorcycle).

Electrical system

The RD500LC features a standard 12-

volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defi ...

electrical system. Yamaha's self-cancelling indicator unit is used and a variable resistance gauging system is used to monitor

two-stroke oil Two-stroke oil (also referred to as two-cycle oil, 2-cycle oil, 2T oil, or 2-stroke oil) is a special type of motor oil intended for use in crankcase compression two-stroke engines, typical of small gasoline-powered engines. Use Unlike a four-s ...

tank contents with associated warning lights. Nippondenso

capacitor discharge ignition Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. It w ...

(CDI) is used in conjunction with two coils.Yamaha service manual

RZV500R

The RZV500R was designed exclusively for the Japanese home market although many have been exported privately. The RZV500R features upgraded parts not found on the standard RD500LC and RZ500. A major difference is the hand-welded aluminium frame, which is significantly lighter than the steel version used on standard models. The water temperature gauge also doubles as a fuel tank contents gauge at the push of a RHS lever (very useful feature given their fuel consumption) and the front-fork preload can be altered from the top of the forks. There is also a red light mounted within the tachometer housing that comes on at the equivalent of 55 mph (Japanese maximum national speed limit). The speedo is of course calibrated in km/h. The front forks are air assisted with rebound damping adjustment. The rear brake and gear levers are cast from aluminium, as are the clip-on type handle bars. These chassis modifications added up to a weight saving of . The engine was detuned to to comply with Japanese legislation. This was achieved by restricting the internal diameter of the exhaust pipes and changes to the carburettor jetting. These restrictions are easily changed to the RD500 specification by opening up the restrictor plates in the exhaust to create the same diameter hole as the exhaust pipes had as standard and the re-jetting of the carburetors to suit.

Models by country

''Differences mentioned are comparisons to the UK specification RD500LC, Yamaha model numbers are in brackets where known. '' *Australia :RZ500N (53G) *Austria :Front and rear yellow side reflectors *Canada :RZ500S (1VW) *Denmark :Self-retracting sidestand, right dip headlight *Finland :Self-retracting side stand, extended rear mudguard, right dip headlight *Germany :Reduced load capacity (205kg instead of 211kg), self-cancelling indicators deleted, right dip headlight *Japan :RZV500R (51X) :Tachometer mounted red warning light that activates at the equivalent of 55mph. Hand-produced lightweight aluminium frame, fuel tank contents gauge activated by a rhs mounted function switch (uses water temp gauge to show fuel tank contents available), front suspension pre-load adjustable from dial on top of forks legs. Self-cancelling indicators deleted. Production run limited to 1600 units only (all sold in the first week of release allegedly) *Norway :Self-retracting sidestand, suppressor spark plug caps, right dip headlight *Sweden :Modified exhaust pipes, self-retracting sidestand, right dip headlight *United Kingdom :RD500LC (47X early models - 1GE late models)

Specifications (RD500LC/RZV500R)

Motorsport

The bike won the

Castrol Six Hour The Castrol Six Hour was a motorcycle race for production motorcycles, held in Australia from 1970 through to 1987. History The race was run by the Willoughby District Motorcycle Club and held at Amaroo Park until 1983, when it was moved to ...

race in 1984.

References

;Notes ;References * Yamaha RD500LC (47X) service manual, Yamaha Motor Co. Ltd 1st edition, June 1984 * Yamaha RD500LC (1GE-Europe) parts manual, Yamaha Motor Co. Ltd, 1985
Motorcycle.com The Grand Prix fantasy

External links

{{Yamaha motorcycles RD500LC, Motorcycles by brand, Yamaha products Sport bikes Motorcycles introduced in 1984 Two-stroke motorcycles