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71-555: Some of the XR series came in two versions: R and L . The R version bikes were enduro machines designed for off-road competitive riding. They were fitted with knobby off-road tires and were not always street legal . The L version models were dual-sport trailbikes, fitted with lights, indicators, horn, and street-legal tires. Small XR models include the XR50R, XR70R, XR75R, XR80R and XR100R. They are much smaller in size in comparison to

142-584: A "Power Up" kit that included a billet 100mm piston, a revised primary gear ratio (identical to that used later in the XR650L) and a hotter camshaft. XR600R's so modified were used by the Honda race team in Baja, as well as by many other desert racers. Introduced in 2000, the XR 650R was not just an update to the XR 600—it was a totally new bike. An all-new 649 cc (39.6 cu in), liquid-cooled , SOHC engine

213-513: A 10:1 compression ratio. A major advance over the XR200, the XR200R had Pro-Link rear suspension, and heavier duty frame and forks, and was a tougher enduro machine. For the 1984-85 model years, the XR200 had a smaller version of the same 4 valve RFVC engine as the other XRs in the line up. The 200cc RFVC engine shared many parts with the 250cc RFVC engine. For the 1986 model year, Honda reverted to

284-453: A 12-litre capacity, the front brake was a single hydraulic disc, and the handlebars sported plastic ‘bark-buster’ hand protectors. The 1984 XR500RE model was the last 500cc XR, being superseded in 1985 by the larger Honda XR 600RF. The XR 600R was used in Baja races. It was introduced in 1985, and was updated in 1988 when the original dual progressively opening carburetors were replaced with

355-408: A 2.8 gallon gas tank with 0.6 gal reserve, the 650L has a 349 lb (158 kg) wet weight. The Honda XR650L is one of the longest running unchanged production models in the history of motorcycling and is still available today exactly as the 1992 model specifications. The Honda XRV650 (produced from 1988 to 1989) was the second twin cylinder production trail bike by Honda, the first one being

426-611: A 23 hp rating. An electric start street version of the XR250R was sold in Asia as the XR250 and Australia as the XR250L. The Honda model designator for it is MD30. It's based on the 1996-2004 model XR250R but with different suspension, fuel tank, rear subframe, electrical system, carburettor, cam shaft and most significantly the addition of electric start. There were two variants of the bike

497-456: A DOHC configuration gradually increased after World War II, beginning with sports cars. Iconic DOHC engines of this period include the 1948–1959 Lagonda straight-six engine , the 1949–1992 Jaguar XK straight-six engine and the 1954–1994 Alfa Romeo Twin Cam inline-four engine. The 1966-2000 Fiat Twin Cam inline-four engine was one of the first DOHC engines to use a toothed timing belt instead of

568-464: A DOHC engine was built in 1910. Use of DOHC engines slowly increased from the 1940s, leading to many automobiles by the early 2000s using DOHC engines. In an OHC engine, the camshaft is located at the top of the engine, above the combustion chamber . This contrasts the earlier overhead valve engine (OHV) and flathead engine configurations, where the camshaft is located down in the engine block . The valves in both OHC and OHV engines are located above

639-441: A completely new engine dubbed the "Radial Four Valve Chamber" (RFVC) engine. The original 250 cc (15 cu in) RFVC engine had a bore and stroke of 75 mm × 56.5 mm (2.95 in × 2.22 in), but in 1986 this was changed to 73 mm × 59.5 mm (2.87 in × 2.34 in). 1986 also saw the adoption of a large, single carburetor rather than the dual progressively opening carburetors of

710-415: A conventional 18" rear wheel but an unusual 23" front wheel which was supposed to be better for riding over potholes and ruts. The 23" size proved unpopular and did not catch on as the wheel/tyre assembly was heavy, and there was little choice of replacement 23" tyres. In 1981 Honda introduced 'Pro-Link’ models, with rising-rate single-shock rear suspension, a 17" rear wheel and a 21" front wheel. Unusual for

781-707: A curved profile such that some tread only contacts the ground during turning. Depending on the model of tire, an off-road capable tire may or may not be approved by the DOT . In the United States, such a tire approved for street use will be marked with a DOT code (U.S.), which identifies the tire as street legal . Tires which are not approved for street use will typically be labeled "Motocross Use Only" or "Not for Highway Use". Street legal, knobby tires are generally not suitable for long distances on roads or paved surfaces because of poor NVH properties and excessive wear on

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852-547: A development of the XL185 trail bike, was produced from 1980 until 1984. The XR200 had a modestly enlarged ohc 2-valve 6-speed air-cooled engine with kick-start only. Suspension was conventional, like the XL185s, but with better quality components and more travel. Although the XR200 power output was modest, the bike was small and light and it suited less experienced riders. Due to its lightness, easy handling and good ground clearance,

923-498: A dry sump, a stroke of 63.8 mm and displacement of 353 cc (21.5 cu in). The wrist pin diameter was reduced from 21 mm to 19 mm and the dual progressive carburetors of the 83-84 models were replaced by a single large carburetor. The XR 400R was introduced in 1996. Its frame, plastics and suspension components were similar to those of the XR250R, and it had a similar air-cooled engine with RFVC cylinder head technology. The XR400R had more suspension travel and

994-407: A four-stroke with its typical intake and exhaust valves, the 1981 and 1982 XR-500 utilized a six-petal reed valve set-up between the carburetor and the intake valves. This was intended to provide better low-end performance while still allowing a large carburetor to be used. The 1982 XR 500RC was very similar to the 1981 RB apart from decal and trim changes. The 1983 XR500R was thoroughly revised with

1065-608: A fully enclosed-drivetrain), the American Liberty L-12 V12 engine, which closely followed the later Mercedes D.IIIa design's partly-exposed SOHC valvetrain design; and the Max Friz -designed; German BMW IIIa straight-six engine. The DOHC Napier Lion W12 engine was built in Great Britain beginning in 1918. Most of these engines used a shaft to transfer drive from the crankshaft up to the camshaft at

1136-449: A large cylinder head to accommodate the camshaft or an extra set of valves to increase the volumetric efficiency , so that with the same displacement as an OHV engine, the OHC engine will end up being the physically larger of the two mostly due to the enlarged cylinder head. The other main advantage of OHC engines is that there is greater flexibility to optimise the size, location and shape of

1207-455: A larger single carburetor and the rear brake was updated to a disc. The 600 was updated again in 1992. The XR won many desert races in the hands of Johnny Campbell and GNCC races in the hands of Scott Summers. Its engine was very similar to the XR 400 and XR 250 engines, (though larger and heavier). 600's responded well to modification. A common modification was to bore the cylinder to 100mm thereby increasing displacement to 628cc. HRC produced

1278-406: A longer wheelbase than the XR250R of the same year. Many XR400Rs were heavily modified and raced. The 400 was perhaps the most versatile of the XR line-up; many were raced in amateur motocross and enduro events. Equipped with street-legal lighting it also worked reasonably well as a dual purpose bike. It was simple, reliable and long lasting. Hard to break and easy to fix. In 2004 Honda discontinued

1349-525: A new dry-sump RFVC 5-speed engine which was lighter and more powerful than the older engine. Induction was by 2 carburetors, the first in use until 1/4 throttle, whereupon the second started to take effect. Power was 41 hp @6000 rpm, torque was 4.7 kg-m (34 lb-ft) at 5500 rpm, and dry weight was 266.7 lbs. The frame was entirely revised, and suspension was updated with 43mm air-adjustable forks with 11" of suspension travel both front and rear. Wheels were 21" front and 17" rear. The fuel tank had

1420-420: A single headlight version that looks more like the standard XR250R and a dual headlight "Baja" version. The XR 350R was introduced for the 1983 model year and discontinued after the 1985 model year. The 1983 and 1984 models were wet sump engines with a bore and stroke of 84 mm × 61.3 mm (3.31 in × 2.41 in) and a displacement of 339 cc (20.7 cu in). The 1985 engine had

1491-554: A slightly tuned 650cc engine similar to the Honda Transalp (XL600V and XL650V) and high specification chassis components, leading to its rather brief production run. With an aftermarket larger capacity tank and very few other modifications the bike was entered in the marathon class of the Paris Dakar Rally , revealing its surprisingly good off-road abilities - despite its 200 kg weight, hence it belongs firmly to

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1562-400: A steel fuel tank, keyed ignition/steering lock, lower seat height and other minor changes. Some 40 lb (18 kg) heavier, it had reduced off-road ability. It shared the XR250R's RFVC 249 cc (15.2 cu in) engine, but with a different carburetor and 3 mm (0.12 in) smaller exhaust headers to meet emissions requirements. It was manufactured from 1991 to 2007. There

1633-407: A total of two camshafts (one for each cylinder bank). Most SOHC engines have two valves per cylinder, one intake valve and one exhaust valve. Motion of the camshaft is usually transferred to the valves either directly (using a tappet) or indirectly via a rocker arm . A dual overhead cam , double overhead cam , or twin-cam engine has two camshafts over each bank of the cylinder head, one for

1704-597: A two-stroke engine for dramatic effect. The XR50 is a small four-stroke 50 cc (3.1 cu in) child's entry level motorcycle, introduced in 1969 and still in production as the CRF50 in 2021. Originally it was called the Z-50, then Trail-50, the XR 50, CRF 50, and the mini dirt bike. The XR100R was first introduced with the R designation in 1985, four years after the XR100 was brought to market. A major difference between

1775-505: Is 130 kg. It has a front disc brake and rear drum brake. A more recent version is the 2023 XR150L released in early 2023 for $ 2971 new. It has a four stroke engine, long travel suspension, and an electric starter. The XR 190L was released in 2019. The 184.4 cc (11.25 cu in) engine 4-stroke, single-cylinder, air-cooled, OHC fuel-injected engine generates 15.6 hp (11.6 kW) at 8,500rpm, Electric and kick starter . The XR 190L produces Max torque of 15.6Nm @ 6000 RPM,

1846-460: Is 137 kg. It has a front disc brake and rear drum brake. In some international markets, there is an agricultural version of the XR19L, rebadged to be a XR190AG aimed at farmers for Australia and New Zealand with additional racks and lowered gearing. A derivative for South America, named XRE 190, has electric start only, and disc brakes featuring single-channel ABS on the front wheel. The XR200,

1917-471: Is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber . This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion chamber in the engine block . Single overhead camshaft (SOHC) engines have one camshaft per bank of cylinders . Dual overhead camshaft (DOHC, also known as "twin-cam" ) engines have two camshafts per bank. The first production car to use

1988-453: Is between 55 and 60 mph (89 and 97 km/h) with a fuel consumption of about 60 mpg ‑US (3.9 L/100 km; 72 mpg ‑imp ). In Brazil, this model was named NXR 125 Bros. The XR 150L was released in 2014. The 150cc 4-stroke, single-cylinder, air-cooled, OHC engine generates 12.14 hp (9.05 kW) at 7,750&;rpm, Electric and kick starter . The XR 150 produces maximum torque of 12.5Nm at 6000 rpm;

2059-468: Is possible. The first known automotive application of timing belts to drive overhead camshafts was the 1953 Devin-Panhard racing specials built for the SCCA H-modified racing series in the United States. These engines were based on Panhard OHV flat-twin engines, which were converted to SOHC engines using components from Norton motorcycle engines. The first production car to use a timing belt

2130-457: Is that the system used to drive the camshaft (usually a timing chain in modern engines) is more complex in an OHC engine, such as the 4-chain valvetrain of the Audi 3.2 or the 2 meter chain on Ford cammers. Another disadvantage of OHC engines is that during engine repairs where the removal of the cylinder head is required, the camshaft engine timing needs to be reset. In addition, an OHC engine has

2201-551: The Duesenberg Model J , which was powered by a DOHC straight-eight engine. The 1931–1935 Stutz DV32 was another early American luxury car to use a DOHC engine. Also in the United States, the DOHC Offenhauser racing engine was introduced in 1933. This inline-four engine dominated North American open-wheel racing from 1934 until the 1970s. Other early SOHC automotive engines were the 1920–1923 Wolseley Ten ,

Honda XR series - Misplaced Pages Continue

2272-660: The Honda XLV750R produced from 1983 to 1986. It was the first twin cylinder model in the XR series and as such started the XRV series, but it was soon replaced by the Honda XRV750 in 1990. The 650cc model was built in Japan by Honda Racing Corporation and is arguably a better built bike than following versions of XRVs, which were standard production models. It came as both single and double headlight variations, and featured

2343-537: The 1903 Marr Auto Car SOHC engine built in the United States. The first DOHC engine was a Peugeot inline-four racing engine which powered the car that won the 1912 French Grand Prix . Another Peugeot with a DOHC engine won the 1913 French Grand Prix , followed by the Mercedes-Benz 18/100 GP with an SOHC engine winning the 1914 French Grand Prix . The Isotta Fraschini Tipo KM — built in Italy from 1910–1914—

2414-427: The 1925-1948 Velocette K series , the 1931-1957 Norton International and the 1947-1962 Norton Manx . In more recent times, the 1950-1974 Ducati Single , 1973-1980 Ducati L-twin engine , 1999-2007 Kawasaki W650 and 2011-2016 Kawasaki W800 motorcycle engines have used bevel shafts. The Crosley four cylinder was the last automotive engine to use the shaft tower design to drive the camshaft, from 1946 to 1952;

2485-417: The 1928-1931 MG 18/80 , the 1926–1935 Singer Junior and the 1928–1929 Alfa Romeo 6C Sport . Early overhead camshaft motorcycles included the 1925–1949 Velocette K Series and the 1927–1939 Norton CS1 . The 1946–1948 Crosley CC Four was arguably the first American mass-produced car to use an SOHC engine. This small mass-production engine powered the winner of the 1950 12 Hours of Sebring . Use of

2556-524: The 2 valve engine that had powered the XR200R before 1984 and variations of the 2 valve engine continued to power the XR200R until the model was dropped altogether.The 1991 model was the best performance wise. Brazilian versions of the XR 200R were introduced in 1992 and remained on production until 2001 for the domestic market and at least until 2015 for export, always fitted with the 2-valve engine, electric start and front disc brake. At least in Australia,

2627-602: The 2010 XR125L has a kick starter . The XR 125L shares the same basic engine (JC30E) as the Honda CG125ES but with a few differences (the XR125L varient of the JC30E engine has larger diameter mounting holes in the engine casing, an engine mount on the cylinder head, and a longer counter shaft in the transmission to support wider rear wheels), and produces a maximum torque of 7 ft-lb, the top speed in real world conditions

2698-469: The 84-85 models. In 1996 the engine of the XR 250R , the mainstay of the XR range, was updated and now produced 19 hp (14 kW) at 8100 rpm. Changes included a new crankcase with better engine mounts (which incorporated the swingarm pivot) for a stiffer chassis, smaller exhaust valves to address a problem with cracking cylinder heads, and an improved automatic decompressor for easier starting. Although

2769-540: The Brazilian-made model was rebadged CTX200 and fitted with a "cheater sprocket" to get an overall lower gear ratio more suitable to the needs of agricultural operators and was not roadworthy as supplied. The XR250R was introduced pre 1981 and was originally equipped with a variation of the engine that had powered the XL250S since 1978. For 1983 the model was dropped from Honda's line-up, but came back in 1984 with

2840-472: The XR 600R, unlike the totally redesigned XR 650R that has a liquid-cooled 649 cc (39.6 cu in) SOHC dry-sump single-cylinder four-stroke engine. The 644 cc (39.3 cu in) engine first appeared in the NX650 Dominator in 1988 which makes it the longest produced RFVC engine made by Honda. With a headlight, taillight, turn signals, mirrors, smog system, revised exhaust system and

2911-556: The XR range. It is the most sought after model of the Africa Twin XRV range and is fast becoming a collector's item, especially in Europe. Knobby tire Off-road tires (Off-road tyre) are a category of vehicle tires that use deep tread to provide more traction on unpaved surfaces such as loose dirt, mud, sand, or gravel. Compared to ice or snow tires, they lack studs but contain deeper and wider grooves meant to help

Honda XR series - Misplaced Pages Continue

2982-417: The XR200 was competitive as a clubman's enduro machine. Drum brakes were fitted front and rear. Having neither battery nor electric start, the driving lights shone only when the engine was running. For the 1979 model year only, there was an XR185 sold in some markets. The Honda XR 200R had the same 195 cc (11.9 cu in) engine of its predecessor, the XR200. This oversquare two-valve engine had

3053-501: The XR250R was always quite heavy compared to its 2 stroke competition and both front and rear suspension were rather basic, it proved reliable and likable and was successful as an entry-level off-road machine. The XR250R was discontinued after 2004. This street version of the XR250R was built to conform to USA Department of Transportation regulations for street legal motorcycles, but was sold worldwide. It had road legal lights and tires,

3124-529: The XR400R. The XR 400M was introduced in 2005, and whilst having a similar engine to the XR 400R, the exhaust diameter is smaller and has a slightly lower power output. It was sold as a factory motard, with road wheels and tyres, electric start, and updated faux radiator fairings. Introduced in 1979, the twin-shock Honda XR 500 was the first "XR" model. The engine was a four-stroke, four-valve OHC , 497 cc (30.3 cu in) "Pentroof" engine. The bike had

3195-519: The block, and were known as "tower shafts". An early American overhead camshaft production engine was the SOHC straight-eight engine used in the 1921–1926 Duesenberg Model A luxury car. In 1926, the Sunbeam 3 litre Super Sports became the first production car to use a DOHC engine. In the United States, Duesenberg added DOHC engines (alongside their existing SOHC engines) with the 1928 release of

3266-415: The camshaft. Timing belts are inexpensive, produce minimal noise and have no need for lubrication. A disadvantage of timing belts is the need for regular replacement of the belt; recommended belt life typically varies between approximately 50,000–100,000 km (31,000–62,000 mi). If the timing belt is not replaced in time and fails and the engine is an interference engine , major engine damage

3337-470: The combustion chamber; however an OHV engine requires pushrods and rocker arms to transfer the motion from the camshaft up to the valves, whereas an OHC engine has the valves directly actuated by the camshaft. Compared with OHV engines with the same number of valves, there are fewer reciprocating components and less valvetrain inertia in an OHC engine. This reduced inertia in OHC engines results in less valve float at higher engine speeds (RPM). A downside

3408-466: The crankshaft and the camshaft is commonly used in diesel overhead camshaft engines used in heavy trucks. Gear trains are not commonly used in engines for light trucks or automobiles. Several OHC engines up until the 1950s used a shaft with bevel gears to drive the camshaft. Examples include the 1908–1911 Maudslay 25/30 , the Bentley 3 Litre , the 1917-? Liberty L-12 , the 1929-1932 MG Midget ,

3479-561: The helm. Cancelled for the 2008 production year, the 'Big Red Pig (BRP)' enjoys a loyal following among Honda fans today, and remains one of the most competitive, open class 4-stroke enduro motorcycles available. The Honda XR650L is a street/trail bike that is more similar to the XR 600R than to the XR 650R. It has a steel tube frame as opposed to an aluminum spar frame like in the XR 650R. It also has an air-cooled 644 cc (39.3 cu in) SOHC dry-sump single-cylinder four-stroke engine similar except for an increased displacement to

3550-432: The intake and exhaust ports, since there are no pushrods that need to be avoided. This improves the gas flow through the engine, increasing power output and fuel efficiency . The oldest configuration of overhead camshaft engine is the single overhead camshaft (SOHC) design. A SOHC engine has one camshaft per bank of cylinders, therefore a straight engine has a total of one camshaft and a V engine or flat engine has

3621-715: The intake valves and another for the exhaust valves. Therefore there are two camshafts for a straight engine and a total of four camshafts for a V engine or a flat engine. A V engine or flat engine requires four camshafts to function as a DOHC engine, since having two camshafts in total would result in only a single camshaft per cylinder bank for these engine layouts. Some V engines with four camshafts have been marketed as "quad-cam" engines, however technically "quad-cam" would require four camshafts per cylinder bank (i.e. eight camshafts in total), therefore these engines are merely dual overhead camshaft engines. Many DOHC engines have four valves per cylinder. The camshaft usually operates

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3692-413: The other bikes in the series, and are designed for children, smaller riders, as pit bikes, or for recreational fun. The XR80R was used in the film Terminator 2: Judgment Day , ridden by a young John Connor ( Edward Furlong ). In some scenes the taller XR100R (VIN H2HE0309LK900900) is the motorcycle from those sequences. is used as Furlong's stunt double was an adult man. The sound effects are that of

3763-454: The rights to the Crosley engine format were bought by a few different companies, including General Tire in 1952, followed by Fageol in 1955, Crofton in 1959, Homelite in 1961, and Fisher Pierce in 1966, after Crosley closed the automotive factory doors, and they continued to produce the same engine for several more years. A camshaft drive using three sets of cranks and rods in parallel

3834-449: The shape of the tread cross-section closer to that of street tires) can provide a compromise, giving less grip off-road, but a grip closer to that of street tires on paved surfaces. Such tires are useful for enduro and dual-sport motorcycles and other vehicles designed to be used both off-road and on pavement. Some off-road tires are designed to be used with low inflation pressure on difficult terrain, reducing their rigidity and allowing

3905-599: The soft rubber. Depending on the design, an off-road tire may be designated "all terrain" ("All-around"), meaning it is intended for use both on- and off-road. Such tires attempt to compromise between grip on loose terrain and safety or comfort on paved roads. Some tires, such as the bar grip used on United States military vehicles in World War II, accomplish this by separating the tire into distinct on-road and off-road tread zones. Modern all-terrain tires typically employ hybrid tread patterns and tougher compound to increase

3976-730: The starting point for both Mercedes' and Rolls-Royce's aircraft engines. Mercedes created a series of six-cylinder engines which culminated in the Mercedes D.III . Rolls-Royce reversed-engineered the Mercedes cylinder head design based on a racing car left in England at the beginning of the war, leading to the Rolls-Royce Eagle V12 engine. Other SOHC designs included the Spanish Hispano-Suiza 8 V8 engine (with

4047-447: The timing between each camshaft and the crankshaft. This affords better fuel economy by allowing a broader torque curve. Although each major manufacturer has their own trade name for their specific system of variable cam phasing systems, overall they are all classified as variable valve timing . The rotation of a camshaft is driven by a crankshaft . Many 21st century engines use a toothed timing belt made from rubber and kevlar to drive

4118-437: The top of the engine. Large aircraft engines— particularly air-cooled engines— experienced considerable thermal expansion, causing the height of the cylinder block to vary during operating conditions. This expansion caused difficulties for pushrod engines, so an overhead camshaft engine using a shaft drive with sliding spline was the easiest way to allow for this expansion. These bevel shafts were usually in an external tube outside

4189-446: The top speed in real world conditions is between 60 and 68 mph (97 and 109 km/h) with a fuel consumption of about 60 mpg ‑US (3.9 L/100 km; 72 mpg ‑imp ). It has a 5-speed gearbox. It has 19 in (480 mm) front wheel and 17 in (430 mm) rear wheel. It has a 12-litre fuel tank and luggage rack as standard. In many countries it can be road-registered but not Australia. Curb weight

4260-599: The top speed in real world conditions is between 65–72 mph (105–116 km/h) with a fuel consumption of about 60 mpg ‑US (3.9 L/100 km; 72 mpg ‑imp ). Other than the larger engine capacity over the XR150L, the XR190L has Fuel Injection. It has a 5 speed gearbox. It has 21 inch front wheel and 18 inch rear wheel. It has a 12-litre fuel tank and luggage rack as standard. In many countries it can be road registered including Australia. Kerb weight

4331-503: The tread sink into mud or gravel surfaces. Off-road tires are typically radials with thick, deep tread. On dirt surfaces, the exposed edges of the tread dig into soft ground to give more traction than rolling friction alone, analogous to the traction provided by cleated shoes . These off-road tires provide their maximum grip on loose surfaces, but on paved surfaces the smaller contact patch affords less traction as compared to street tires. Tires with less aggressive knobs (smaller knobs and

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4402-425: The tread to better conform to the terrain. Such a design may allow for use on a wider range of surfaces, but tubeless tires running under rated pressure run the risk of breaking their bead. A beadlock can be used to prevent this. Off-road cycle tires, colloquially called knobbies , may be found on motocross and enduro motorcycles, ATVs , and mountain bikes . Tires for single-track vehicles and ATVs have

4473-465: The two was a major rear suspension upgrade to a more race-like single coil-over design (monoshock) and a new swingarm over the traditional dual real coil-over systems on the XR100. This suspension system was known as the Pro-Link system on Hondas. In some markets, an XR125L was released in 2003. The 124 cc (7.6 cu in) engine generates 11.52 hp (8.59 kW) at 4,500&;rpm, Only

4544-414: The valves directly via a bucket tappet . A DOHC design permits a wider angle between intake and exhaust valves than in SOHC engines, which improves the air-fuel mixture's flow through the engine. A further benefit is that the spark plug can be placed at the optimum location, which in turn improves combustion efficiency . Another newer benefit of DOHC engine design is the ability to independently change/phase

4615-617: The vast majority of mud-terrain tyres max out at a tyre speed rating of "Q" (160kph). Mud-terrain tyres, may improve traction and have reduced braking distances on dirt roads where the rocks slightly are too big to fit into the grooves and channels of an all-terrain tyre. Traditionally mud-terrain tyres are uncomfortable, loud, dangerous and inefficient (high fuel use and tyre wear) to use on paved roads/asphalt highways. Modern mud-terrain tyres have similar characteristics to high quality aggressive (high void) all-terrain tyres. Overhead camshaft engine An overhead camshaft ( OHC ) engine

4686-783: The wear life under mixed-surface conditions. All-terrain tires are known for their ability to handle different terrains. They come with grooves and channels that distribute the load evenly, improving the traction. This makes all-terrain tires ideal for off-road driving, snow and ice, sand, and other soft surfaces. They are also known for their long lasting performance. Some of the key features of all-terrain tires (ATTs). Design for mudding , rock crawling or desert racing (especially for bulldust or baja silt ). Most mud-terrain tyres are road legal (DOT approved), but maybe prevented from being fitted to modern cars due to laws on minimum tyre speed rating. Most modern cars, SUV and pickup trucks require minimum tyre speed rating of "S" (180kph), but

4757-519: Was a Brazilian equivalent named XR 250 Tornado made from 2001 to 2009 (until 2012 for export) for the local market and regional exports to other South American countries but also available in Mexico and Central America. Its engine was the same 4-valve DOHC air-cooled single fitted to the CBX 250 Twister/CBF 250, but the exhaust was dimensioned to improve low-end torque with the sacrifice of 1 hp resulting in

4828-550: Was mated to an aluminum box frame. At 280 lb (130 kg) dry, it weighed more than the XR600R which it replaced, but was built very strong and the engine was immensely powerful. Honda was obviously aiming squarely at the long range desert racing market with this bike. Team Honda and the XR650R posted many definitive Baja 1000 wins during its production cycle, and many other desert race wins with Scott Summers and Johnny Campbell at

4899-520: Was one of the first production cars to use an SOHC engine. During World War I, both the Allied and Central Powers ; specifically those of the German Empire 's Luftstreitkräfte air forces, sought to quickly apply the overhead camshaft technology of motor racing engines to military aircraft engines. The SOHC engine from the Mercedes 18/100 GP car (which won the 1914 French Grand Prix) became

4970-472: Was the 1962 Glas 1004 compact coupe. Another camshaft drive method commonly used on modern engines is a timing chain , constructed from one or two rows of metal roller chains . By the early 1960s most production automobile overhead camshaft designs used chains to drive the camshaft(s). Timing chains do not usually require replacement at regular intervals, however the disadvantage is that they are noisier than timing belts. A gear train system between

5041-474: Was used in the 1920–1923 Leyland Eight luxury car built in the United Kingdom. A similar system was used in the 1926-1930 Bentley Speed Six and the 1930-1932 Bentley 8 Litre . A two-rod system with counterweights at both ends was used by many models of the 1958-1973 NSU Prinz . Among the first overhead camshaft engines were the 1902 Maudslay SOHC engine built in the United Kingdom and

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