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Yamaha YZ 250
The Yamaha YZ250 is a two-stroke motocross race bike made by Yamaha. The model was launched in 1974 and has been regularly updated and is still in production with new releases every year. Engine The original YZ250 of 1974 used an air-cooled 250cc two-stroke engine of 70 mm bore and a 64 mm stroke, which was improved semi-annually. The air-cooled motor was replaced in 1982 with a 249 cc liquid-cooled two-stroke reed-valved engine with a YPVS exhaust valve for a wider spread of power. The bore on the water-cooled engine was reduced to 68 mm and the stroke was increased to 68 mm producing a displacement of 247 cc. In 1999, the bore was further reduced to 66.4 mm and the stroke lengthened to 72 mm producing a displacement of 249 cc. The longer stroke engine resulted in a lower redline, slightly less top end power and greatly improved torque at lower RPM. The engine produces a peak at 8,800 rpm and of torque at 7,500 rpm, with a 9,000 rpm r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamaha Motor Company
is a Japanese multinational manufacturer of motorcycles, marine products such as boats and outboard motors, and other motorized products. The company was established in 1955 upon separation from Yamaha Corporation (however, Yamaha Corporation is still the largest private company shareholder with 9.92%, as of 2019), and is headquartered in Iwata, Shizuoka, Japan. The company conducts development, production and marketing operations through 109 consolidated subsidiaries as of 2012. Led by Genichi Kawakami, the company's founder and first president, Yamaha Motor spun off from musical instrument manufacturer Yamaha Corporation in 1955 and began production of its first product, the YA-1 125cc motorcycle. It was quickly successful and won the 3rd Mount Fuji Ascent Race in its class. The company's products include motorcycles, scooters, motorized bicycles, boats, sail boats, personal water craft, swimming pools, utility boats, fishing boats, outboard motors, 4-wheel ATVs, recreat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamaha YZ450F
The Yamaha YZ450F is a four-stroke racing motocross bike built by Yamaha Motor Corporation. It was the successor to the previous YZ426F which was discontinued in 2003. It is credited by ''Cycle World'' and ''Dirt Rider'' magazines as the bike that started the four-stroke dirt bike revolution. The 2006 YZ250F and YZ450F were the first production motorcycles equipped with titanium suspension springs. The WR450F is the enduro version of the YZ450F. Introduction For many years, the motocross world almost exclusively used two-stroke engines. AMA racing classes had two classes: 125 cc and 250 cc two-strokes, with no provision for four strokes. Most riders considered four-stroke engine technology to be largely utilitarian and uncompetitive, relegated solely for trail riding. In 1996, the AMA changed racing rules to allow 450 cc four strokes to compete in the same racing class as 250 cc two-strokes. Yamaha engineer Yoshiharu Nakayama first came up with the idea of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motocross
Motocross is a form of off-road motorcycle racing held on enclosed off-road circuits. The sport evolved from motorcycle trials competitions held in the United Kingdom. History Motocross first evolved in Britain from motorcycle trials competitions, such as the Auto-Cycle Clubs's first quarterly trial in 1909 and the Scottish Six Days Trial that began in 1912. When organisers dispensed with delicate balancing and strict scoring of trials in favour of a race to become the fastest rider to the finish, the activity became known as "hare scrambles", said to have originated in the phrase, "a rare old scramble" describing one such early race. Though known as scrambles racing (or just scrambles) in the United Kingdom, the sport grew in popularity and the competitions became known internationally as "motocross racing", by combining the French word for motorcycle, ''motocyclette'', or ''moto'' for short, into a portmanteau with "cross country". The first known scramble race took place ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-cylinder Engine
A single-cylinder engine, sometimes called a thumper, is a piston engine with one cylinder. This engine is often used for motorcycles, motor scooters, go-karts, all-terrain vehicles, radio-controlled vehicles, portable tools and garden machinery (such as lawnmowers, cultivators, and string trimmers). Single-cylinder engines are made both as 4-strokes and 2-strokes. Characteristics 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 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-stroke Engine
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time. Two-stroke engines often have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the power band. Two-stroke engines have fewer moving parts than four-stroke engines. History The first commercial two-stroke engine involving cylinder compression is attributed to Scottish engineer Dugald Clerk, who patented his design in 1881. However, unlike most later two-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 fiber). Applications Traditional Reed valves, normally a leather flap covering a hole, are amongst the earliest form of automatic flow control for liquids and gases. They have been used for thousands of years in water pumps and for hundreds of years in bellows for high-temperature forges and musical instruments such as church organs and accordions. In nature, heart valves operate in a somewhat similar fashion. Pumps Reed valves are used in some reciprocating compressor designs, and in the pumping element of some musical instruments, large and small. Two-stroke engines Reed valves are commonly used in high-performance versions of the two-stroke engine, where they control the fuel-air mixture admitted to the cylinder. As the piston ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-stroke Power Valve System
{{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 piston travelling the full length of its cylinder. In a two-stroke engine, one of the two strokes combines the intake stroke and the compression stroke, while the other stroke combines the combustion stroke and the exhaust stroke. As the piston travels upward in the cylinder, it creates low pressure area in the crankcase; this draws fresh air and atomized fuel from the carburetor through a hole in the cylinder wall or directly into the crankcase. As the piston continues travelling upward, transfer ports and the exhaust ports are closed off, thus trapping the combustible mixture in the combustion chamber. As the piston reaches the top of the cylinder, the mixture in the cylinder is compressed to the point of ignition. The second stroke beg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoshock
A motorcycle's suspension serves a dual purpose: contributing to the vehicle's handling and braking, and providing safety and comfort by keeping the vehicle's passengers comfortably isolated from road noise, bumps and vibrations. The typical motorcycle has a pair of fork tubes for the front suspension, and a swingarm with one or two shock absorbers for the rear suspension. Front suspension The most common form of front suspension for a modern motorcycle is the telescopic fork. Other fork designs are girder forks, suspended on sprung parallel links (not common since the 1940s) and bottom leading link designs, not common since the 1960s. Some manufacturers (e.g. Greeves) used a version of the swinging arm for front suspension on their motocross designs. A single-sided version of the idea is also used in motor scooters such as the Vespa. The hub-center steering as developed by Ascanio Rodorigo, on a concept associated to Massimo Tamburini is a complex front swingarm alternat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kayaba Industry
is a Japanese, Tokyo-based automotive company. Among KYB's main products company are shock absorbers, air suspensions, power steering systems, hydraulic pumps, motors, cylinders, and valves. It is one of the world's largest shock absorber manufacturers and it also has the largest market share of concrete mixer trucks in Japan, with 85% of the market. The company has 34 manufacturing plants and 62 offices in 21 countries. KYB's American aftermarket distribution of automotive shocks and struts is headquartered in Greenwood, IN, with additional KYB manufacturing and distribution facilities in metro Chicago, Southern California, and metro Indianapolis. KYB Americas employs more than 100 people in all facilities. Shocks and struts for vehicles are the most popular KYB products distributed in North America. Business segments and products Automotive and motorcycle products Automotive components * Shock absorbers * Semi-active air suspensions * Adjustable shock absorbers * Power ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chad Reed
Chad Mark Reed (born 15 March 1982, in Kurri Kurri, Australia) is an Australian motocross and supercross racer. He is a multi-time champion record holder for the most main event starts in AMA Supercross history, with 265 starts as of 21 June 2020, his career spanning almost 20 years. He was taught from a young age to be capable of competing at the sport's most elite level. He has proven to be the most consistent supercross/motocross racer in the 2000–2009 decade and has grown to be one of the sport's most loved individuals, due to his years of experience and dedication to his sport. He has since ascended the international ranks of the sport to become Australia's most successful motocross racer. Amateur career As a small child, Chad owned a horse named Fern. After his cousin Craig Anderson started riding a bike, Chad instantly discovered his love for motorcycles and decided to trade in his much-loved horse in place for his first-ever bike - a Yamaha PW50. The family soon pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YZ85 Yamaha
The Yamaha YZ 85 is a motorcycle designed specifically for off-road and Motorcross racing. 85 It is powered by an 84.7 cc single-cylinder, water-cooled, two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of ..., reed valve inducted engine and uses a 6-speed, constant-mesh, manual gearbox; with a multi-plate, wet- clutch. There are two wheel options – large wheel, with a 19-inch front and 16-inch rear; and small wheel, with a 17-inch front and 14-inch rear. It weighs 157 lbs (wet). References Yamaha motorcycles Two-stroke motorcycles {{motorcycle-stub sv:Yamaha YZ85 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamaha YZ125
The Yamaha YZ125 is a motocross racing motorcycle with a Two-stroke engine, two-stroke Engine displacement, displacement single-cylinder engine made by Yamaha Motor Company, Yamaha since 1974. It is available to the public. For the first two years it was made with dual rear shocks, then changing to a monoshock. The YZ125 has been ridden to five AMA National Motocross Championships, and multiple AMA Regional Supercross Championships. In 2001, Yamaha released a bike designed to complement the YZ125, the four-stroke YZ250F. The two bikes shared a rolling chassis and are eligible to compete in the same racing class. The YZ250F has a slight horsepower advantage. The YZ125 has a Reed valve#Two-stroke engines, reed valve-inducted two-stroke engine. It was air cooled from 1974 to 1980, and liquid cooled since 1981. It has a Mikuni (company), Mikuni 38 mm TMX series carburetor. The engine produces . The YZ125 has been built with five- or six-speed sequential gearbox, manual sequent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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