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58-494: The motorcycle enters motorcycling's ADV (adventure) segment, straddles Adventure , Sport-Touring and Dual Sport descriptions, trading strength in a single area for adaptability to a variety of riding conditions: commuting, adventure touring, and to a lesser degree, off-road riding. The ADV segment had grown significantly prior to Harley Davidson's entry. The Pan America is powered by a liquid-cooled 1,250 cc 60 degree Revolution Max V-twin engine . Industry analysts said it

116-447: A flathead engine a push rod is not necessary. The overhead cam design typically allows higher engine speeds because it provides the most direct path between cam and valve. Valve clearance refers to the small gap between a valve lifter and a valve stem that ensures that the valve completely closes. On engines with mechanical valve adjustment, excessive clearance causes noise from the valve train. A too-small valve clearance can result in

174-591: A sport bike and a dual-sport. Four-stroke engine A four-stroke (also four-cycle ) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed: Four-stroke engines are the most common internal combustion engine design for motorized land transport, being used in automobiles , trucks , diesel trains , light aircraft and motorcycles . The major alternative design

232-504: A clean sheet of paper and design a new model designed for a specific combination of dirt and street use. These motorcycles are usually heavier and more durable than the models derived from off-road motorcycles. This approach is currently taken by Aprilia, BMW, Honda, Kawasaki, Moto Guzzi, Suzuki, and Yamaha. Several manufacturers modify street motorcycles to make them more dirt worthy. These bikes are usually more at home on pavement. Finally, owners add street-legal equipment to off-road bikes. In

290-493: A replica of the Lenoir engine in 1861, Otto became aware of the effects of compression on the fuel charge. In 1862, Otto attempted to produce an engine to improve on the poor efficiency and reliability of the Lenoir engine. He tried to create an engine that would compress the fuel mixture prior to ignition, but failed as that engine would run no more than a few minutes prior to its destruction. Many other engineers were trying to solve

348-515: A sense, all motorcycles at that time were dual-sports, intended to be used on dirt as well as pavement. Advertisements well into the 1920s depict motorcycles on dirt roads, raising clouds of dust. By 1940, most roads in developed countries were paved and motorcycles had become heavier and more oriented to the street. In the 1950s and 1960s British manufacturers such as Triumph and BSA offered versions of their relatively light street motorcycles with high exhaust pipes, and called them scramblers. Yamaha

406-583: A turbine system that converted waste heat into kinetic energy that it fed back into the engine's transmission. In 2005, BMW announced the development of the turbosteamer , a two-stage heat-recovery system similar to the Mack system that recovers 80% of the energy in the exhaust gas and raises the efficiency of an Otto engine by 15%. By contrast, a six-stroke engine may reduce fuel consumption by as much as 40%. Modern engines are often intentionally built to be slightly less efficient than they could otherwise be. This

464-413: Is a contact surface on which the cam slides to open the valve. Many engines use one or more camshafts "above" a row (or each row) of cylinders, as in the illustration, in which each cam directly actuates a valve through a flat tappet. In other engine designs the camshaft is in the crankcase , in which case each cam usually contacts a push rod , which contacts a rocker arm that opens a valve, or in case of

522-402: Is a type of motorcycle that is designed for varying degrees of off-road use while still being street-legal . Dual-sports may be equipped with lights , a speedometer , mirrors , a horn , registration plates , and a muffler to comply with local regulations. Other names such as all-road , on/off-road , dual-purpose , and adventure bike may be chosen by the manufacturer based upon

580-467: Is closer to the top. Diesel engines by their nature do not have concerns with pre-ignition. They have a concern with whether or not combustion can be started. The description of how likely Diesel fuel is to ignite is called the Cetane rating. Because Diesel fuels are of low volatility, they can be very hard to start when cold. Various techniques are used to start a cold Diesel engine, the most common being

638-729: Is common for dual sport owners to customise their bike to match the type of terrain or roads on which they ride. Changing tires, handlebars, seats, bash plates or foot pegs are common modifications. Adding large petrol tanks, racks, luggage and wind screens are common for riders intending to travel far. Dual sport aftermarket parts and accessories are manufactured and available worldwide. When dual-sports are fitted for long-distance travel with accessories such as oversized gas tanks, luggage, and other distance-oriented gear, they are often referred to as " adventure bikes ". These motorcycles offer touring capabilities, but are less comfortable on long pavement trips than full-fledged touring motorcycles such as

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696-402: Is credited with rekindling popular interest in dirt worthy motorcycles that could also be ridden on the street. In 1968 they introduced the hugely successful DT-1 based on a 250 cc two-stroke engine . Other manufacturers soon followed with similar models called " enduros ". These light weight machines were good on trails and adequate on pavement. Some manufacturers approached the trend from

754-424: Is designed to provide efficiency at the expense of power density , and is used in some modern hybrid electric applications. The original Atkinson-cycle piston engine allowed the intake, compression, power, and exhaust strokes of the four-stroke cycle to occur in a single turn of the crankshaft and was designed to avoid infringing certain patents covering Otto-cycle engines. Due to the unique crankshaft design of

812-536: Is limited by the chemical composition of the fuel. There are several grades of fuel to accommodate differing performance levels of engines. The fuel is altered to change its self ignition temperature. There are several ways to do this. As engines are designed with higher compression ratios the result is that pre-ignition is much more likely to occur since the fuel mixture is compressed to a higher temperature prior to deliberate ignition. The higher temperature more effectively evaporates fuels such as gasoline, which increases

870-609: Is necessary for emission controls such as exhaust gas recirculation and catalytic converters that reduce smog and other atmospheric pollutants. Reductions in efficiency may be counteracted with an engine control unit using lean burn techniques . In the United States, the Corporate Average Fuel Economy mandates that vehicles must achieve an average of 34.9 mpg ‑US (6.7 L/100 km; 41.9 mpg ‑imp ) compared to

928-431: Is not immediately available due to the need to sharply increase engine RPM, to build up pressure and to spin up the turbo, before the turbo starts to do any useful air compression. The increased intake volume causes increased exhaust and spins the turbo faster, and so forth until steady high power operation is reached. Another difficulty is that the higher exhaust pressure causes the exhaust gas to transfer more of its heat to

986-414: Is regarded as the first car. In 1884, Otto's company, then known as Gasmotorenfabrik Deutz (GFD), developed electric ignition and the carburetor. In 1890, Daimler and Maybach formed a company known as Daimler Motoren Gesellschaft . Today, that company is Daimler-Benz . The Atkinson-cycle engine is a type of single stroke internal combustion engine invented by James Atkinson in 1882. The Atkinson cycle

1044-400: Is that the temperature rise of the compressed charge can cause pre-ignition. If this occurs at the wrong time and is too energetic, it can damage the engine. Different fractions of petroleum have widely varying flash points (the temperatures at which the fuel may self-ignite). This must be taken into account in engine and fuel design. The tendency for the compressed fuel mixture to ignite early

1102-581: Is the two-stroke cycle . Nikolaus August Otto was a traveling salesman for a grocery concern. In his travels, he encountered the internal combustion engine built in Paris by Belgian expatriate Jean Joseph Etienne Lenoir . In 1860, Lenoir successfully created a double-acting engine that ran on illuminating gas at 4% efficiency. The 18 litre Lenoir Engine produced only 2 horsepower. The Lenoir engine ran on illuminating gas made from coal, which had been developed in Paris by Philip Lebon . In testing

1160-412: Is ultimately limited by material strength and lubrication . Valves, pistons and connecting rods suffer severe acceleration forces. At high engine speed, physical breakage and piston ring flutter can occur, resulting in power loss or even engine destruction. Piston ring flutter occurs when the rings oscillate vertically within the piston grooves they reside in. Ring flutter compromises the seal between

1218-793: The DR350 in 1990 and promoted it as a DualSport or “ dirt bike with a license plate”. The terms "dual-sport" and “dualie” were quickly adopted by riders and the motorcycle press. Manufacturers use several different names for their dual-sport models. Suzuki uses DualSport to describe its products. Kawasaki describes its offerings as dual purpose, Honda lists its entry under off-road, and other manufacturers describe machines as enduros, or simply list them as model numbers. A few models are described as "adventure bikes". Despite these differences in terminology, these models can be described as dual-sports, which are street-legal motorcycles that can be operated on pavement, dirt roads and trails. Dual-sport motorcycles are

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1276-512: The Honda Goldwing series. A supermoto (also known as a supermotard or motard) is typically a converted motocross bike with less suspension travel, smaller front and rear wheels (typically 17" at both ends), road tires and an oversized front brake designed to be primarily run on asphalt. When made street legal, these bikes may also be considered to be a type of dual-sport. In this case, these motorbikes could be seen as somewhere between

1334-590: The fuel economy improvements the Atkinson cycle can provide. The diesel engine is a technical refinement of the 1876 Otto-cycle engine. Where Otto had realized in 1861 that the efficiency of the engine could be increased by first compressing the fuel mixture prior to its ignition, Rudolf Diesel wanted to develop a more efficient type of engine that could run on much heavier fuel. The Lenoir , Otto Atmospheric, and Otto Compression engines (both 1861 and 1876) were designed to run on Illuminating Gas (coal gas) . With

1392-433: The Atkinson, its expansion ratio can differ from its compression ratio and, with a power stroke longer than its compression stroke, the engine can achieve greater thermal efficiency than a traditional piston engine. While Atkinson's original design is no more than a historical curiosity, many modern engines use unconventional valve timing to produce the effect of a shorter compression stroke/longer power stroke, thus realizing

1450-630: The SL350 still borrowed heavily from the CB350 platform. By 1971, the Honda SL350 K1 and the later K2 had been completely transformed from a heavy, unyielding, unpredictable, unequipped off-roader into a nimble, user friendly, trail champion. This line of Dual Sports continued to evolve into the popular XL series of Honda Dual Sports. BMW changed the game with the introduction of the R80 G/S in 1980,

1508-586: The US, some states license only motorcycles that met highway emissions requirements when first sold, while others allow off-road vehicles to be converted to on-road. Dual-sports may be grouped by weight and intended purpose. These types are only approximate and new models that split the boundaries and offer different combinations of features appear each year. However, the laws of momentum and inertia always favor lighter dual-sports for tight, rough trails. Heavier dual-sports that emphasize rider comfort, wind protection and

1566-525: The actual four-stroke and two-stroke cycles is not a simple task. However, the analysis can be simplified significantly if air standard assumptions are utilized. The resulting cycle, which closely resembles the actual operating conditions, is the Otto cycle. During normal operation of the engine, as the air/fuel mixture is being compressed, an electric spark is created to ignite the mixture. At low rpm this occurs close to TDC (Top Dead Centre). As engine rpm rises,

1624-426: The air has been compressed twice and then gains more potential volume in the combustion but it is only expanded in one stage. A turbocharger is a supercharger that is driven by the engine's exhaust gases, by means of a turbine . A turbocharger is incorporated into the exhaust system of a vehicle to make use of the expelled exhaust. It consists of a two piece, high-speed turbine assembly with one side that compresses

1682-452: The bore diameter is larger than its stroke length is an oversquare engine, conversely, an engine with a bore diameter that is smaller than its stroke length is an undersquare engine. The valves are typically operated by a camshaft rotating at half the speed of the crankshaft . It has a series of cams along its length, each designed to open a valve during the appropriate part of an intake or exhaust stroke. A tappet between valve and cam

1740-562: The capacity to carry luggage are better choices for long highway trips at higher speeds. Dual-sports, by definition, are compromises - giving up some dirt performance to be ridden on the street and some street performance to be ridden in the dirt. The merits of a particular model can only be judged relative to the owner’s intended mix of dirt and street riding. Although aficionados may argue the merits of different models, versatile dual-sports can be desirable alternatives to more specialized motorcycles that can only be ridden in one environment. It

1798-436: The current standard of 25 mpg ‑US (9.4 L/100 km; 30.0 mpg ‑imp ). As automakers look to meet these standards by 2016, new ways of engineering the traditional internal combustion engine (ICE) have to be considered. Some potential solutions to increase fuel efficiency to meet new mandates include firing after the piston is farthest from the crankshaft, known as top dead centre , and applying

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1856-474: The efficiency of the compression engine. Higher compression ratios also mean that the distance that the piston can push to produce power is greater (which is called the expansion ratio ). The octane rating of a given fuel is a measure of the fuel's resistance to self-ignition. A fuel with a higher numerical octane rating allows for a higher compression ratio, which extracts more energy from the fuel and more effectively converts that energy into useful work while at

1914-502: The energy generated by combustion is converted into useful rotational energy at the output shaft of the engine, while the remainder being lost due to waste heat, friction and engine accessories. There are a number of ways to recover some of the energy lost to waste heat. The use of a turbocharger in diesel engines is very effective by boosting incoming air pressure and in effect, provides the same increase in performance as having more displacement. The Mack Truck company, decades ago, developed

1972-412: The engine's performance and/or fuel efficiency could be improved by improving the overall efficiency of the cycle. It has been found that even if 6% of the entirely wasted heat is recovered it can increase the engine efficiency greatly. Many methods have been devised in order to extract waste heat out of an engine exhaust and use it further to extract some useful work, decreasing the exhaust pollutants at

2030-560: The engines burst, nearly killing Diesel. He persisted, and finally created a successful engine in 1893. The high-compression engine, which ignites its fuel by the heat of compression, is now called the diesel engine, whether a four-stroke or two-stroke design. The four-stroke diesel engine has been used in the majority of heavy-duty applications for many decades. It uses a heavy fuel containing more energy and requiring less refinement to produce. The most efficient Otto-cycle engines run near 30% thermal efficiency. The thermodynamic analysis of

2088-420: The first high-speed Otto engine in 1883. In 1885, they produced the first automobile to be equipped with an Otto engine. The Daimler Reitwagen used a hot-tube ignition system and the fuel known as Ligroin to become the world's first vehicle powered by an internal combustion engine. It used a four-stroke engine based on Otto's design. The following year, Karl Benz produced a four-stroke engined automobile that

2146-910: The first large adventure dual sport machine and the ancestor of the adventure sport category that is so popular today. Modified versions of the R80 G/S won the gruelling Paris Dakar race four times in five years between 1981 and 1985, and Helge Pedersen rode one for 10 years and 250,000 miles in an around-the-world journey that helped cement the G/S's place in motorcycling history. Over the next 20 years, manufacturers began producing heavier and less dirt worthy enduros based on four-stroke engines , as they searched for better combinations of weight, power, durability, performance and comfort. The heavier machines were better on longer highway rides but less popular with “real” dirt riders, who began modifying them to create lighter and more competent trail machines. Suzuki introduced

2204-434: The intake air, and the other side that is powered by the exhaust gas outflow. When idling, and at low-to-moderate speeds, the turbine produces little power from the small exhaust volume, the turbocharger has little effect and the engine operates nearly in a naturally aspirated manner. When much more power output is required, the engine speed and throttle opening are increased until the exhaust gases are sufficient to 'spool up'

2262-416: The lightest dual-sport offered by Suzuki Motor Corporation in 2008 weighs about 250 pounds (110 kg) and has a small single-cylinder engine with barely enough power for highway use. The heaviest dual-sport offered by Suzuki Motor Corporation in 2008 weighs about 460 pounds (210 kg) and has a large two-cylinder engine with plenty of power for long freeway trips. Accordingly, it is necessary to refer to

2320-448: The manufacturers specifications for a particular model to learn more about its intended use. There are four ways of creating dual-sports. Some manufacturers add street-legal equipment to existing off-road motorcycles. These bikes are usually light and powerful, at the expense of shorter service life and higher maintenance. This approach is currently taken by European manufacturers such as KTM and Husqvarna . Other manufacturers start with

2378-424: The mechanical parts of the engine. The rod-to-stroke ratio is the ratio of the length of the connecting rod to the length of the piston stroke. A longer rod reduces sidewise pressure of the piston on the cylinder wall and the stress forces, increasing engine life. It also increases the cost and engine height and weight. A "square engine" is an engine with a bore diameter equal to its stroke length. An engine where

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2436-402: The most practical choice in rural areas in many parts of the world, and when traveling on unpaved trails they can often be a necessity. Terms such as dual-sport, enduro and adventure bike are marketing descriptions, not strict definitions of weight, power, and intended usage. Generally a dual sport is less than 400 pounds while bikes above 400 pounds are considered adventure bikes. For example,

2494-678: The opposite direction, beginning with a street motorcycle and modifying it for adequate off-road performance. For instance, the Honda CL350 Scrambler was a variation on the Honda CB350 street motorcycle with high exhaust pipes, a larger front wheel, dirt-oriented tires, and lower gearing. As a partial response to Yamaha’s success with the DT-1, in 1969 Honda produced the SL350 K0. Considered Honda’s first real production Dual Sport,

2552-415: The piston speed for industrial engines to about 10 m/s. The output power of an engine is dependent on the ability of intake (air–fuel mixture) and exhaust matter to move quickly through valve ports, typically located in the cylinder head . To increase an engine's output power, irregularities in the intake and exhaust paths, such as casting flaws, can be removed, and, with the aid of an air flow bench ,

2610-421: The power output limits of an internal combustion engine relative to its displacement. Most commonly, the supercharger is always running, but there have been designs that allow it to be cut out or run at varying speeds (relative to engine speed). Mechanically driven supercharging has the disadvantage that some of the output power is used to drive the supercharger, while power is wasted in the high pressure exhaust, as

2668-472: The problem, with no success. In 1864, Otto and Eugen Langen founded the first internal combustion engine production company, NA Otto and Cie (NA Otto and Company). Otto and Cie succeeded in creating a successful atmospheric engine that same year. The factory ran out of space and was moved to the town of Deutz , Germany in 1869, where the company was renamed to Deutz Gasmotorenfabrik AG (The Deutz Gas Engine Manufacturing Company). In 1872, Gottlieb Daimler

2726-497: The radii of valve port turns and valve seat configuration can be modified to reduce resistance. This process is called porting , and it can be done by hand or with a CNC machine. An internal combustion engine is on average capable of converting only 40-45% of supplied energy into mechanical work. A large part of the waste energy is in the form of heat that is released to the environment through coolant, fins etc. If somehow waste heat could be captured and turned to mechanical energy,

2784-399: The ring and the cylinder wall, which causes a loss of cylinder pressure and power. If an engine spins too quickly, valve springs cannot act quickly enough to close the valves. This is commonly referred to as ' valve float ', and it can result in piston to valve contact, severely damaging the engine. At high speeds the lubrication of piston cylinder wall interface tends to break down. This limits

2842-502: The same motivation as Otto, Diesel wanted to create an engine that would give small industrial companies their own power source to enable them to compete against larger companies, and like Otto, to get away from the requirement to be tied to a municipal fuel supply. Like Otto, it took more than a decade to produce the high-compression engine that could self-ignite fuel sprayed into the cylinder. Diesel used an air spray combined with fuel in his first engine. During initial development, one of

2900-406: The same time preventing engine damage from pre-ignition. High Octane fuel is also more expensive. Many modern four-stroke engines employ gasoline direct injection or GDI. In a gasoline direct-injected engine, the injector nozzle protrudes into the combustion chamber. The direct fuel injector injects gasoline under a very high pressure into the cylinder during the compression stroke, when the piston

2958-498: The same time. Use of the Rankine Cycle , turbocharging and thermoelectric generation can be very useful as a waste heat recovery system. One way to increase engine power is to force more air into the cylinder so that more power can be produced from each power stroke. This can be done using some type of air compression device known as a supercharger , which can be powered by the engine crankshaft. Supercharging increases

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3016-496: The size, weight, and intended application of the motorcycle. Typically the dual sport category weighs less than 400 pounds/180 kilos to make them more comfortable and capable off road while adventure bikes are more than 400 pounds/180 kilos to make them more comfortable and capable on road. The concept of a versatile motorcycle equally at home on dirt and pavement is as old as motorcycling itself. Most roads were still unpaved when motorized bicycles first appeared around 1900. In

3074-452: The speed of the flame front does not change so the spark point is advanced earlier in the cycle to allow a greater proportion of the cycle for the charge to combust before the power stroke commences. This advantage is reflected in the various Otto engine designs; the atmospheric (non-compression) engine operates at 12% efficiency whereas the compressed-charge engine has an operating efficiency around 30%. A problem with compressed charge engines

3132-407: The turbocharger's turbine to start compressing much more air than normal into the intake manifold. Thus, additional power (and speed) is expelled through the function of this turbine. Turbocharging allows for more efficient engine operation because it is driven by exhaust pressure that would otherwise be (mostly) wasted, but there is a design limitation known as turbo lag . The increased engine power

3190-423: The use of a glow plug . The maximum amount of power generated by an engine is determined by the maximum amount of air ingested. The amount of power generated by a piston engine is related to its size (cylinder volume), whether it is a two-stroke engine or four-stroke design, volumetric efficiency , losses, air-to-fuel ratio, the calorific value of the fuel, oxygen content of the air and speed ( RPM ). The speed

3248-438: The valves not closing properly. This results in a loss of performance and possibly overheating of exhaust valves. Typically, the clearance must be readjusted each 20,000 miles (32,000 km) with a feeler gauge. Most modern production engines use hydraulic lifters to automatically compensate for valve train component wear. Dirty engine oil may cause lifter failure. Otto engines are about 30% efficient; in other words, 30% of

3306-532: Was most likely to compete with street-oriented adventure tourers like the BMW R1250GS . During its ownership of the Buell Motorcycle Company , Harley Davidson offered a similar offroad-capable Ulysses XB12X, beginning in 2005. This motorcycle, scooter or moped-related article is a stub . You can help Misplaced Pages by expanding it . Adventure motorcycle A dual-sport motorcycle

3364-406: Was technical director and Wilhelm Maybach was the head of engine design. Daimler was a gunsmith who had worked on the Lenoir engine. By 1876, Otto and Langen succeeded in creating the first internal combustion engine that compressed the fuel mixture prior to combustion for far higher efficiency than any engine created to this time. Daimler and Maybach left their employ at Otto and Cie and developed

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