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66-595: The Triumph Tiger Cub was a 200 cc (12 cu in) single-cylinder British motorcycle made by Triumph Motorcycles at their Meriden factory. Based on the Triumph T15 Terrier 150 cc, itself a surprise announcement just before the 1952 show, the 200 cc T20 Tiger Cub was designed by Edward Turner , and launched at the Earls Court show in November 1953. It competed well against

132-716: A four-stroke cycle ), however diesel single-cylinder engines are also used in stationary applications (such as the Lombardini 3LD and 15LD). A variation known as the split-single makes use of two pistons which share a single combustion chamber. Early motorcycles , automobiles and other applications such as marine engines all tended to be single-cylinder. The configuration is almost exclusively used in portable tools, along with garden machinery such as lawn mowers. Single cylinder engines also remain in widespread use in motorcycles, motor scooters , go-karts , auto rickshaws , and radio-controlled models . From 1921 to 1960,

198-454: A fuel for spark-ignited internal combustion engines . When formulated as a fuel for engines , gasoline is chemically composed of organic compounds derived from the fractional distillation of petroleum and later chemically enhanced with gasoline additives . It is a high-volume profitable product produced in crude oil refineries. The fuel-characteristics of a particular gasoline-blend, which will resist igniting too early are measured as

264-648: A 'distributor'-type device on the crankcase behind the cylinder. A later development in 1963 was to site the points at a more conventional location on the end of the camshaft, accessed via a chrome cover below the base of the cylinder. The Sports Cub designated T20SH featured slimline mudguards, no rear panelling or headlamp nacelle and with a higher compression ratio and other engine modifications were timed at 74 mph mean maximum by Motor Cycle magazine. Off-road versions produced with high level exhaust, altered suspension and studded tyres, were designated TS20 Scrambles Cub and TR20 Trials Cub . The last model made

330-583: A 49 cc (3.0 cu in) four-stroke single-cylinder engine. There are also several single-cylinder sportbikes (such as the KTM 690 Duke R ), dual-sport motorcycles (such as the BMW G650GS ) and the classic-styled Royal Enfield 500 Bullet . The Moto3 class in the MotoGP World Championship have used four-stroke 250 cc (15.3 cu in) single cylinder engines since

396-456: A condition called "stale fuel". Gasoline containing ethanol is especially subject to absorbing atmospheric moisture, then forming gums, solids, or two phases (a hydrocarbon phase floating on top of a water-alcohol phase). The presence of these degradation products in the fuel tank or fuel lines plus a carburetor or fuel injection components makes it harder to start the engine or causes reduced engine performance On resumption of regular engine use,

462-449: A controlled process called deflagration . However, the unburned mixture may autoignite by pressure and heat alone, rather than igniting from the spark plug at exactly the right time, causing a rapid pressure rise that can damage the engine. This is often referred to as engine knocking or end-gas knock. Knocking can be reduced by increasing the gasoline's resistance to autoignition , which is expressed by its octane rating. Octane rating

528-443: A fine mist. Quality gasoline should be stable for six months if stored properly, but can degrade over time. Gasoline stored for a year will most likely be able to be burned in an internal combustion engine without too much trouble. However, the effects of long-term storage will become more noticeable with each passing month until a time comes when the gasoline should be diluted with ever-increasing amounts of freshly made fuel so that

594-470: A greater volume fraction of aromatics. Finished marketable gasoline is traded (in Europe) with a standard reference of 0.755 kilograms per liter (6.30 lb/U.S. gal), (7,5668 lb/ imp gal) its price is escalated or de-escalated according to its actual density. Because of its low density, gasoline floats on water, and therefore water cannot generally be used to extinguish a gasoline fire unless applied in

660-412: A growing annual target of total gallons blended. Although the mandate does not require a specific percentage of ethanol, annual increases in the target combined with declining gasoline consumption have caused the typical ethanol content in gasoline to approach 10 percent. Most fuel pumps display a sticker that states that the fuel may contain up to 10 percent ethanol, an intentional disparity that reflects

726-574: A high compression ratio. A high expansion ratio is also one of the two key reasons for the efficiency of diesel engines , along with the elimination of pumping losses due to throttling of the intake airflow. The lower energy content of LPG by liquid volume in comparison to gasoline is due mainly to its lower density. This lower density is a property of the lower molecular weight of propane (LPG's chief component) compared to gasoline's blend of various hydrocarbon compounds with heavier molecular weights than propane. Conversely, LPG's energy content by weight

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792-401: A higher compression ratio through the concomitant higher expansion ratio on the power stroke, which is by far the greater effect. The higher expansion ratio extracts more work from the high-pressure gas created by the combustion process. An Atkinson cycle engine uses the timing of the valve events to produce the benefits of a high expansion ratio without the disadvantages, chiefly detonation, of

858-411: A maximum of 250cc. The Tiger Cub became one of the most popular ways of getting onto two wheels. Single-cylinder engine Compared with multi-cylinder engines, single-cylinder engines are usually simpler and compact. Due to the greater potential for airflow around all sides of the cylinder, air cooling is often more effective for single cylinder engines than multi-cylinder engines. This reduces

924-643: A nation with a good supply of high-octane gasoline would have the advantage in air power. In 1943, the Rolls-Royce Merlin aero engine produced 980 kilowatts (1,320 hp) using 100 RON fuel from a modest 27 liters (1,600 cu in) displacement. By the time of Operation Overlord , both the RAF and USAAF were conducting some operations in Europe using 150 RON fuel (100/150 avgas ), obtained by adding 2.5 percent aniline to 100-octane avgas. By this time,

990-417: A representative species, performs the chemical reaction: By weight, combustion of gasoline releases about 46.7 megajoules per kilogram (13.0  kWh /kg; 21.2 MJ/ lb ) or by volume 33.6 megajoules per liter (9.3 kWh/L; 127 MJ/U.S. gal; 121,000 BTU/U.S. gal), quoting the lower heating value . Gasoline blends differ, and therefore actual energy content varies according to

1056-739: Is 10 percent ethanol, and 98E5, which is 5 percent ethanol. Most gasoline sold in Sweden has 5–15 percent ethanol added. Three different ethanol blends are sold in the Netherlands—E5, E10 and hE15. The last of these differs from standard ethanol–gasoline blends in that it consists of 15 percent hydrous ethanol (i.e., the ethanol–water azeotrope ) instead of the anhydrous ethanol traditionally used for blending with gasoline. The Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) requires gasoline for automobile use to have 27.5 percent of ethanol added to its composition. Pure hydrated ethanol

1122-426: Is a mixture of paraffins ( alkanes ), olefins ( alkenes ), napthenes ( cycloalkanes ), and aromatics . The use of the term paraffin in place of the standard chemical nomenclature alkane is particular to the oil industry (which relies extensively on jargon). The composition of a gasoline depends upon: The various refinery streams blended to make gasoline have different characteristics. Some important streams include

1188-457: Is a naturally colorless liquid, many gasolines are dyed in various colors to indicate their composition and acceptable uses. In Australia, the lowest grade of gasoline (RON 91) was dyed a light shade of red/orange, but is now the same color as the medium grade (RON 95) and high octane (RON 98), which are dyed yellow. In the U.S., aviation gasoline ( avgas ) is dyed to identify its octane rating and to distinguish it from kerosene-based jet fuel, which

1254-509: Is also available as a fuel. Legislation requires retailers to label fuels containing ethanol on the dispenser, and limits ethanol use to 10 percent of gasoline in Australia. Such gasoline is commonly called E10 by major brands, and it is cheaper than regular unleaded gasoline. The federal Renewable Fuel Standard (RFS) effectively requires refiners and blenders to blend renewable biofuels (mostly ethanol) with gasoline, sufficient to meet

1320-460: Is called E85 . The most extensive use of ethanol takes place in Brazil , where the ethanol is derived from sugarcane . In 2004, over 13 billion liters (3.4 × 10 ^  U.S. gal) of ethanol was produced in the U.S. for fuel use, mostly from corn and sold as E10. E85 is slowly becoming available in much of the U.S., though many of the relatively few stations vending E85 are not open to

1386-478: Is derived from a 160-liter (42 U.S. gal) barrel of crude oil . Material separated from crude oil via distillation , called virgin or straight-run gasoline, does not meet specifications for modern engines (particularly the octane rating ; see below), but can be pooled to the gasoline blend. The bulk of a typical gasoline consists of a homogeneous mixture of hydrocarbons with between 4 and 12 carbon atoms per molecule (commonly referred to as C4–C12). It

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1452-490: Is higher than gasoline's due to a higher hydrogen -to- carbon ratio. Molecular weights of the species in the representative octane combustion are 114, 32, 44, and 18 for C 8 H 18 , O 2 , CO 2 , and H 2 O, respectively; therefore one kilogram (2.2 lb) of fuel reacts with 3.51 kilograms (7.7 lb) of oxygen to produce 3.09 kilograms (6.8 lb) of carbon dioxide and 1.42 kilograms (3.1 lb) of water. Spark-ignition engines are designed to burn gasoline in

1518-422: Is left colorless. In Canada, the gasoline for marine and farm use is dyed red and is not subject to fuel excise tax in most provinces. Oxygenate blending adds oxygen -bearing compounds such as MTBE , ETBE , TAME , TAEE , ethanol , and biobutanol . The presence of these oxygenates reduces the amount of carbon monoxide and unburned fuel in the exhaust. In many areas throughout the U.S., oxygenate blending

1584-501: Is mandated by EPA regulations to reduce smog and other airborne pollutants. For example, in Southern California fuel must contain two percent oxygen by weight, resulting in a mixture of 5.6 percent ethanol in gasoline. The resulting fuel is often known as reformulated gasoline (RFG) or oxygenated gasoline, or, in the case of California, California reformulated gasoline (CARBOB). The federal requirement that RFG contain oxygen

1650-448: Is measured relative to a mixture of 2,2,4-trimethylpentane (an isomer of octane ) and n- heptane . There are different conventions for expressing octane ratings, so the same physical fuel may have several different octane ratings based on the measure used. One of the best known is the research octane number (RON). The octane rating of typical commercially available gasoline varies by country. In Finland , Sweden , and Norway , 95 RON

1716-458: Is sporadic or seasonal (little to no use for one or more seasons of the year). Users have been advised to keep gasoline containers more than half full and properly capped to reduce air exposure, to avoid storage at high temperatures, to run an engine for ten minutes to circulate the stabilizer through all components prior to storage, and to run the engine at intervals to purge stale fuel from the carburetor. Gasoline stability requirements are set by

1782-493: Is the standard for regular unleaded gasoline and 98 RON is also available as a more expensive option. In the United Kingdom, over 95 percent of gasoline sold has 95 RON and is marketed as Unleaded or Premium Unleaded. Super Unleaded, with 97/98 RON and branded high-performance fuels (e.g., Shell V-Power, BP Ultimate) with 99 RON make up the balance. Gasoline with 102 RON may rarely be available for racing purposes. In

1848-763: Is used in Canada and the U.S. to boost octane rating. Its use in the U.S. has been restricted by regulations, although it is currently allowed. Its use in the European Union is restricted by Article 8a of the Fuel Quality Directive following its testing under the Protocol for the evaluation of effects of metallic fuel-additives on the emissions performance of vehicles. Gummy, sticky resin deposits result from oxidative degradation of gasoline during long-term storage. These harmful deposits arise from

1914-486: The Lanz Bulldog tractor used a large horizontally-mounted single cylinder two-stroke engine. However they are rarely used in modern automobiles and tractors, due to developments in engine technology. Single cylinder engines remain the most common engine layout in motor scooters and low-powered motorcycles . The Honda Super Cub (the motor vehicle with the highest overall sales since its introduction in 1958) uses

1980-449: The U.S. Clean Air Act banned the sale of leaded fuel for use in on-road vehicles in the U.S. The use of TEL also necessitated other additives, such as dibromoethane . European countries began replacing lead-containing additives by the end of the 1980s, and by the end of the 1990s, leaded gasoline was banned within the entire European Union with an exception for Avgas 100LL for general aviation . The UAE started to switch to unleaded in

2046-533: The octane rating of the fuel blend. Gasoline blends with stable octane ratings are produced in several fuel-grades for various types of motors. A low octane rated fuel may cause engine knocking and reduced efficiency in reciprocating engines . Tetraethyl lead was once widely used to increase the octane rating but are not used in modern automotive gasoline due to the health hazard . Aviation, off-road motor vehicles, and racing car motors still use leaded gasolines. Interest in gasoline-like fuels started with

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2112-477: The Rolls-Royce Merlin 66 was developing 1,500 kilowatts (2,000 hp) using this fuel. Gasoline, when used in high- compression internal combustion engines, tends to auto-ignite or "detonate" causing damaging engine knocking (also called "pinging" or "pinking"). To address this problem, tetraethyl lead (TEL) was widely adopted as an additive for gasoline in the 1920s. With a growing awareness of

2178-692: The U.S., octane ratings in unleaded fuels vary between 85 and 87 AKI (91–92 RON) for regular, 89–90 AKI (94–95 RON) for mid-grade (equivalent to European regular), up to 90–94 AKI (95–99 RON) for premium (European premium). As South Africa's largest city, Johannesburg , is located on the Highveld at 1,753 meters (5,751 ft) above sea level, the Automobile Association of South Africa recommends 95-octane gasoline at low altitude and 93-octane for use in Johannesburg because "The higher

2244-410: The addition of 5–100 ppm of antioxidants , such as phenylenediamines and other amines . Hydrocarbons with a bromine number of 10 or above can be protected with the combination of unhindered or partially hindered phenols and oil-soluble strong amine bases, such as hindered phenols. "Stale" gasoline can be detected by a colorimetric enzymatic test for organic peroxides produced by oxidation of

2310-457: The altitude the lower the air pressure, and the lower the need for a high octane fuel as there is no real performance gain". Octane rating became important as the military sought higher output for aircraft engines in the late 1920s and the 1940s. A higher octane rating allows a higher compression ratio or supercharger boost, and thus higher temperatures and pressures, which translate to higher power output. Some scientists even predicted that

2376-588: The announcement "the end of one toxic era". However, leaded gasoline continues to be used in aeronautic, auto racing, and off-road applications. The use of leaded additives is still permitted worldwide for the formulation of some grades of aviation gasoline such as 100LL , because the required octane rating is difficult to reach without the use of leaded additives. Different additives have replaced lead compounds. The most popular additives include aromatic hydrocarbons , ethers ( MTBE and ETBE ), and alcohols , most commonly ethanol . Lead replacement petrol (LRP)

2442-521: The benzene limit is set at one percent by volume for all grades of automotive gasoline. This is usually achieved by avoiding feeding C6, in particular cyclohexane , to the reformer unit, where it would be converted to benzene. Therefore, only (desulfurized) heavy virgin naphtha (HVN) is fed to the reformer unit Gasoline can also contain other organic compounds , such as organic ethers (deliberately added), plus small levels of contaminants, in particular organosulfur compounds (which are usually removed at

2508-612: The buildup may or may not be eventually cleaned out by the flow of fresh gasoline. The addition of a fuel stabilizer to gasoline can extend the life of fuel that is not or cannot be stored properly, though removal of all fuel from a fuel system is the only real solution to the problem of long-term storage of an engine or a machine or vehicle. Typical fuel stabilizers are proprietary mixtures containing mineral spirits , isopropyl alcohol , 1,2,4-trimethylbenzene or other additives . Fuel stabilizers are commonly used for small engines, such as lawnmower and tractor engines, especially when their use

2574-456: The class replaced 125 cc (7.6 cu in) two-strokes in 2012 . Engines of other sorts, like the beam engine and certain types of Stirling engine , operate using one cylinder and thus can also be considered single-cylinder engines. Petrol Gasoline ( North American English ) or petrol ( Commonwealth English ) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as

2640-539: The cover and the crankcase itself, making the oil-level even more difficult to maintain in the future. Another common complaint was that the Cub would travel at highway speed (50 mph) for 1/2 hour and then stop unexpectedly. Some attributed this to overheating, but a cure was never found. In 1961, the driving licence law for Triumph's home market in Great Britain was changed, restricting learner motorcyclists to

2706-519: The early 2000s. Reduction in the average lead content of human blood may be a major cause for falling violent crime rates around the world including South Africa. A study found a correlation between leaded gasoline usage and violent crime (see Lead–crime hypothesis ). Other studies found no correlation. In August 2021, the UN Environment Programme announced that leaded petrol had been eradicated worldwide, with Algeria being

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2772-418: The end of production for cars using leaded gasoline in member states. At this stage, a large percentage of cars from the 1980s and early 1990s which ran on leaded gasoline were still in use, along with cars that could run on unleaded fuel. However, the declining number of such cars on British roads saw many gasoline stations withdrawing LRP from sale by 2003. Methylcyclopentadienyl manganese tricarbonyl (MMT)

2838-405: The following: The terms above are the jargon used in the oil industry, and the terminology varies. Currently, many countries set limits on gasoline aromatics in general, benzene in particular, and olefin (alkene) content. Such regulations have led to an increasing preference for alkane isomers, such as isomerate or alkylate, as their octane rating is higher than n-alkanes. In the European Union,

2904-419: The gas) that can withstand the vapor pressure of the gasoline without venting (to prevent the loss of the more volatile fractions) at a stable cool temperature (to reduce the excess pressure from liquid expansion and to reduce the rate of any decomposition reactions). When gasoline is not stored correctly, gums and solids may result, which can corrode system components and accumulate on wet surfaces, resulting in

2970-653: The gasoline. Gasolines are also treated with metal deactivators , which are compounds that sequester (deactivate) metal salts that otherwise accelerate the formation of gummy residues. The metal impurities might arise from the engine itself or as contaminants in the fuel. Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion and allow easier starting in cold climates. High levels of detergent can be found in Top Tier Detergent Gasolines . The specification for Top Tier Detergent Gasolines

3036-461: The invention of internal combustion engines suitable for use in transportation applications. The so-called Otto engines were developed in Germany during the last quarter of the 19th century. The fuel for these early engines was a relatively volatile hydrocarbon obtained from coal gas . With a boiling point near 85 °C (185 °F) ( n -octane boils at 125.62 °C (258.12 °F) ), it

3102-400: The last country to deplete its reserves. UN Secretary-General António Guterres called the eradication of leaded petrol an "international success story". He also added: "Ending the use of leaded petrol will prevent more than one million premature deaths each year from heart disease, strokes and cancer, and it will protect children whose IQs are damaged by exposure to lead". Greenpeace called

3168-406: The older gasoline may be used up. If left undiluted, improper operation will occur and this may include engine damage from misfiring or the lack of proper action of the fuel within a fuel injection system and from an onboard computer attempting to compensate (if applicable to the vehicle). Gasoline should ideally be stored in an airtight container (to prevent oxidation or water vapor mixing in with

3234-527: The other small-capacity motorcycles of the time, such as those using two-stroke engines from Villiers . The first T20 Tiger Cub (1954-1956) was derived from the 150 cc Triumph T15 Terrier (1953-1956) with the same frame and forks . The earlier version of the Cub used the Terrier's plunger rear suspension frame, but from 1957 this was updated to a more modern pattern of rear swinging-arm with twin suspension units. The ignition points were positioned in

3300-455: The oxidation of alkenes and other minor components in gasoline (see drying oils ). Improvements in refinery techniques have generally reduced the susceptibility of gasolines to these problems. Previously, catalytically or thermally cracked gasolines were most susceptible to oxidation. The formation of gums is accelerated by copper salts, which can be neutralized by additives called metal deactivators . This degradation can be prevented through

3366-414: The percentage of lighter products compared to simple distillation. Commercial gasoline as well as other liquid transportation fuels are complex mixtures of hydrocarbons. The performance specification also varies with season, requiring less volatile blends during summer, in order to minimize evaporative losses. Gasoline is produced in oil refineries . Roughly 72 liters (19 U.S. gal) of gasoline

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3432-454: The phaseout of leaded motor fuels in the United Kingdom, Australia , South Africa , and some other countries. Consumer confusion led to a widespread mistaken preference for LRP rather than unleaded, and LRP was phased out 8 to 10 years after the introduction of unleaded. Leaded gasoline was withdrawn from sale in Britain after 31 December 1999, seven years after EEC regulations signaled

3498-427: The refinery). On average, U.S. petroleum refineries produce about 19 to 20 gallons of gasoline, 11 to 13 gallons of distillate fuel diesel fuel and 3 to 4 gallons of jet fuel from each 42 gallon (152 liters) barrel of crude oil. The product ratio depends upon the processing in an oil refinery and the crude oil assay . The specific gravity of gasoline ranges from 0.71 to 0.77, with higher densities having

3564-445: The season and producer by up to 1.75 percent more or less than the average. On average, about 74 liters (20 U.S. gal) of gasoline are available from a barrel of crude oil (about 46 percent by volume), varying with the quality of the crude and the grade of the gasoline. The remainder is products ranging from tar to naphtha . A high-octane-rated fuel, such as liquefied petroleum gas (LPG), has an overall lower power output at

3630-701: The seriousness of the extent of environmental and health damage caused by lead compounds, however, and the incompatibility of lead with catalytic converters , governments began to mandate reductions in gasoline lead. In the U.S., the Environmental Protection Agency issued regulations to reduce the lead content of leaded gasoline over a series of annual phases, scheduled to begin in 1973 but delayed by court appeals until 1976. By 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales and under 1,800 metric tons (2,000 short tons; 1,800 long tons) of lead per year. From 1 January 1996,

3696-455: The standard ASTM D4814. This standard describes the various characteristics and requirements of automotive fuels for use over a wide range of operating conditions in ground vehicles equipped with spark-ignition engines. A gasoline-fueled internal combustion engine obtains energy from the combustion of gasoline's various hydrocarbons with oxygen from the ambient air, yielding carbon dioxide and water as exhaust. The combustion of octane ,

3762-408: The typical 10:1 compression ratio of an engine design optimized for gasoline fuel. An engine tuned for LPG fuel via higher compression ratios (typically 12:1) improves the power output. This is because higher-octane fuels allow for a higher compression ratio without knocking, resulting in a higher cylinder temperature, which improves efficiency . Also, increased mechanical efficiency is created by

3828-510: The varying actual percentage. In parts of the U.S., ethanol is sometimes added to gasoline without an indication that it is a component. In October 2007, the Government of India decided to make five percent ethanol blending (with gasoline) mandatory. Currently, 10 percent ethanol blended product (E10) is being sold in various parts of the country. Ethanol has been found in at least one study to damage catalytic converters. Though gasoline

3894-467: The vibration level, they often make greater use of balance shafts than multi-cylinder engines, as well as more extreme methods such as a dummy connecting rod (for example the Ducati Supermono ). These balancing devices can reduce the benefits of single-cylinder engines regarding lower weight and complexity. Most single-cylinder engines used in motor vehicles are fueled by petrol (and use

3960-437: The weight and complexity of air-cooled single-cylinder engines, compared with liquid-cooled engines. Drawbacks of single-cylinder engines include a more pulsating power delivery through each cycle and higher levels of vibration. The uneven power delivery means that often a single-cylinder engine requires a heavier flywheel than a comparable multi-cylinder engine, resulting in relatively slower changes in engine speed. To reduce

4026-633: Was developed by four automakers: GM , Honda , Toyota , and BMW . According to the bulletin, the minimal U.S. EPA requirement is not sufficient to keep engines clean. Typical detergents include alkylamines and alkyl phosphates at a level of 50–100 ppm. In the EU, 5 percent ethanol can be added within the common gasoline spec (EN 228). Discussions are ongoing to allow 10 percent blending of ethanol (available in Finnish, French and German gasoline stations). In Finland, most gasoline stations sell 95E10, which

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4092-402: Was developed for vehicles designed to run on leaded fuels and incompatible with unleaded fuels. Rather than tetraethyllead, it contains other metals such as potassium compounds or methylcyclopentadienyl manganese tricarbonyl (MMT); these are purported to buffer soft exhaust valves and seats so that they do not suffer recession due to the use of unleaded fuel. LRP was marketed during and after

4158-478: Was dropped on 6 May 2006 because the industry had developed VOC -controlled RFG that did not need additional oxygen. MTBE was phased out in the U.S. due to groundwater contamination and the resulting regulations and lawsuits. Ethanol and, to a lesser extent, ethanol-derived ETBE are common substitutes. A common ethanol-gasoline mix of 10 percent ethanol mixed with gasoline is called gasohol or E10, and an ethanol-gasoline mix of 85 percent ethanol mixed with gasoline

4224-412: Was recovered by internal bracing of the petrol tank. A plain bearing on the timing side main bearing sometimes wore rapidly. The primary chain ran in a shallow oil-bath but if the level dropped, the chain could suffer lubrication failure and stretch. The chain was not tensioned - and even worse, the primary chaincase on early models was a slightly 'waisted' shape. A worn chain could strike both the inside of

4290-624: Was the T20 Super Cub, which, for economy of production cost, used a basic frame and other parts common to the BSA Bantam D10 including larger diameter wheels with full-width hubs. Launched in November 1966, it was discontinued in 1968, being briefly replaced by the 250cc TR25W 'Trophy' , based on BSA's B25 Starfire . The top frame tube of the Tiger Cub was lower than normal, leaving the headstock poorly supported. Some rigidity

4356-516: Was well-suited for early carburetors (evaporators). The development of a "spray nozzle" carburetor enabled the use of less volatile fuels. Further improvements in engine efficiency were attempted at higher compression ratios , but early attempts were blocked by the premature explosion of fuel, known as knocking . In 1891, the Shukhov cracking process became the world's first commercial method to break down heavier hydrocarbons in crude oil to increase

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