Honda CB750

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Honda CB750
HONDA DREAM-CB750FOUR.jpg
1969 Honda CB750
Manufacturer Honda
Also called Honda Dream CB750 Four[1]
Production 1969–2003, 2007
Assembly Wakō, Saitama, Japan
Hamamatsu, Shizuoka Prefecture, Japan
Suzuka, Mie, Japan[2]
Successor CB900F
Class Sport bike or standard
Engine 736 cc (44.9 cu in) SOHC air-cooled straight four (1969-1978)[1]
DOHC air-cooled straight 4 (1979–2003, 2007)
Bore / stroke 61 mm × 63 mm (2.4 in × 2.5 in)[1]
Top speed 125 mph (201 km/h)
Power

68 hp (51 kW) @ 8,500 rpm (1969)[3]

67 hp (50 kW) @ 8,000 rpm (DIN)[1][4]
Torque 44 lbf·ft (60 N·m) @ 7,000 rpm
Transmission 5-speed
Suspension Front: telescopic forks
Rear: swingarm with two spring/shock units.
Brakes Front disc / Rear drum
Tires Front: 3.25" x 19"
Rear: 4.00" x 18"
Rake, trail 3.7 in (94 mm)
Wheelbase 57.3 in (1,460 mm)
Dimensions L: 85 in (2,200 mm)
W: 35 in (890 mm)
H: 44 in (1,100 mm)
Seat height 31 in (790 mm)
Weight 218 kg (481 lb)[1] (dry)
491 lb (223 kg) (wet)
Fuel capacity 19 L (4.2 imp gal; 5.0 US gal)[1]
Fuel consumption 34.3 mpg-US (6.86 L/100 km; 41.2 mpg-imp)[5]

The Honda CB750 is an air-cooled transverse in-line four cylinder engine motorcycle made by Honda over several generations for year models 1969-2003 as well as 2007 with an upright or standard riding posture. It is often called the original Universal Japanese Motorcycle (UJM).[4][6]

Though other manufacturers had marketed the transverse, overhead camshaft, inline four-cylinder engine configuration and the layout had been used in racing engines prior to World War II, Honda popularized the configuration with the CB750, and the layout subsequently became the dominant sport bike engine layout.

The CB750 is included in the AMA Motorcycle Hall of Fame Classic Bikes;[7][8] was named in the Discovery Channel's "Greatest Motorbikes Ever;"[9] was in The Art of the Motorcycle exhibition,[10] and is in the UK National Motor Museum.[11] The Society of Automotive Engineers of Japan, Inc. rates the 1969 CB750 as one of the 240 Landmarks of Japanese Automotive Technology.[1]

The CB750 was the first motorcycle to be called a "superbike."[5][10]

History[edit]

Honda of Japan introduced the CB750 motorcycle to the US and European markets in 1969 after experiencing success with its smaller motorcycles. In the late 1960s Honda motorcycles were, overall, the world's biggest sellers. There were the C100 Club step-through - the biggest selling motorcycle of all time - the C71, C72, C77 and CA77/8 Dreams; and the CB72/77 Super Hawks/Sports. A taste of what was ahead came with the introduction of the revolutionary CB450 DOHC twin-cylinder machine in 1966. Profits from these production bikes financed the successful racing machines of the 1960s, and lessons learned from racing were applied to the CB750. The CB750 was targeted directly at the US market after Honda officials, including founder Soichiro Honda, repeatedly met with US dealers and understood the opportunity for a larger bike.

In 1967 American Honda's service manager Bob Hansen flew to Japan and discussed with Soichiro Honda the possibility of using Grand Prix technology in bikes prepared for American motorcycle events. American racing's governing body, the AMA, had rules that allowed racing by production machines only. Honda knew that what won on the race track today, sold in the show rooms tomorrow, and a large engine capacity road machine would have to be built to compete with the Harley Davidson and Triumph twin-cylinder machines.

Hansen told Mr Honda that he should build a 'King of Motorcycles' and at the Tokyo Show of October 1968 and the Brighton Show of April 1969 the CB750 was launched. Hansen's race team's historical victory at the 1970 Daytona 200 with Dick Mann riding a tall-geared CB750 to victory saw Honda cease all motorcycle road-racing activities and the beginning of the era of the 'Superbike'.[2][12]

Under development for a year,[13] the CB750 had a transverse, straight-four engine with a single overhead camshaft (SOHC) and a front disc brake, neither of which was previously available on a mainstream, affordable, production motorcycle. Having a four cylinder engine and disc brakes, along with the introductory price of US$1,495[14] (US$9,614 in current money), gave the CB750 a considerable sporting performance advantage over its competition, particularly its British rivals.

Cycle magazine called the CB750, "the most sophisticated production bike ever", on the bike's introduction.[14] Cycle World called it a masterpiece, highlighting Honda's painstaking durability testing, the bike's 120 mph (190 km/h) top speed, the fade-free braking, the comfortable ride, and excellent instrumentation.[13]

The CB750 was the first modern four-cylinder machine from a mainstream manufacturer,[15] and the term superbike was coined to describe it.[4][8] Adding to the bike's value were its electric starter, kill switch, dual mirrors, flashing turn signals, easily maintained valves, and overall smoothness and low vibration both underway and at a standstill. Later models, from 1991, included maintenance-free hydraulic valves.

Unable to accurately gauge demand for the new bike, Honda limited its initial investment in the production dies for the CB750 by using a technique called permanent mold casting (often erroneously referred to as sandcasting) rather than diecasting for the engines[16] – unsure of the bike's reception. The bike remained in the Honda line up for ten years, with a production total over 400,000.[17]

Models[edit]

Annual and cumulative production statistics, separated by SOHC (to 1978) and DOHC (1979 and later)

Note: All CB750 engines are air/oil cooled, as opposed to liquid cooled

SOHC[18][edit]

  • 1969 CB750 (6 June), CB750K or CB750K0 (date unknown)
  • 1970 CB750K1 (21 September)
  • 1971 CB750K2 (USA 1 March)
  • 1973 CB750K3 (USA only 1 February. K2 elsewhere)
  • 1974 CB750K4 (US/Japan-only, K2 elsewhere)
  • 1975 CB750K5 (US-only, K2/K4 elsewhere), CB750FO, CB750A (Canada-only)[19] The 1975 CB750F had a more streamlined look, thanks in part to a 4-into-1 exhaust and cafe style seat with fiberglass rear. Other changes included the use of a rear disc brake and a lighter crankshaft and flywheel.
  • 1976 CB750K6, CB750F1, CB750A
  • 1977 CB750K7, CB750F2, CB750A1
  • 1978 CB750K8 (US-only), CB750F3, CB750A2

Production (rounded figures)

CB750K0 53,400
CB750K1 77,000
CB750K2 63,500
CB750K3 38,000
CB750K4 60,000
CB750K5 35,000
CB750K6 42,000
CB750K7 38,000
CB750K8 39,000
CB750F 15,000
CB750F1 44,000
CB750F2 25,000
CB750F3 18,400
CB750A 4,100
CB750A1 2,300
CB750A2 1,700[20]

DOHC[edit]

  • 1979–1982 CB750K
  • 1979 CB750K 10th Anniversary Edition (5,000 produced for US)
  • 1979–1982 CB750F
  • 1980–1982 CB750C "Custom"
  • 1982–1983 CB750SC Nighthawk
  • 1984-1985 CB750SC Nighthawk "S" in Canada
  • 1984-1985 CB700SC Nighthawk "S" in US
  • 1984–1986 CB750SC Nighthawk (Horizon in Japan)
  • 1992-1997 CB750F2
  • 1991–2003 CB750 Nighthawk
  • 2007 CB750 (Japan-only)

CB750A Hondamatic[edit]

CB750A
Also called Hondamatic
Production 1976–1978[21]
Engine 736.6 cc (44.95 cu in) inline-four, SOHC air-cooled
Bore / stroke 61 mm × 63 mm (2.4 in × 2.5 in)
Compression ratio 7.7:1
Power 47 hp (35 kW) @ 7,500 rpm[21]
Torque 5.0 kg·m (49 N·m; 36 lbf·ft) @ 6,000 rpm[21]
Ignition type Coil
Transmission Two speed, w/torque converter, chain
Brakes Front: 296 mm (11.7 in) disc
Rear: 180 mm (7.1 in) drum
Tires Front: 3.5" x 19"
Rear: 4.5" x 17"
Wheelbase 58.1 in (1,480 mm)
Dimensions L: 89.0 in (2,260 mm)
W: 33.7 in (860 mm)
Fuel capacity 18 l (4.0 imp gal; 4.8 US gal)

In 1976, Honda introduced the CB750A to the United States, with the A suffix designating "automatic," for its automatic transmission. Although the two-speed transmission includes a torque converter typical of an automatic transmission, the transmission does not automatically change gears for the rider. Each gear is selected by a foot-controlled hydraulic valve/selector (similar in operation to a manual transmission motorcycle).[21][22] The foot selector controls the application of high pressure oil to a single clutch pack (one clutch for each gear), causing the selected clutch (and gear) to engage. The selected gear remains selected until changed by the rider, or the kickstand is lowered (which shifts the transmission to neutral).[23]

The CB750A was sold in the North American market only.[22] The name Hondamatic was shared with Honda cars of the 1970s, but the motorcycle transmission was not fully automatic. The design of the transmission is similar in concept to the transmission in Honda's N360AT,[23][24] a kei car sold in Japan from 1967 to 1972.

The CB750A uses the same engine as the CB750, but detuned with lower 7.7:1 compression and smaller carburetors producing a lower output, 47.0 hp (35.0 kW). The same oil is used for the engine and transmission, and the engine was changed to a wet sump instead of dry sump type. A lockout safety device prevents the transmission from moving out of neutral if the side stand is down. There is no tachometer but the instruments include a fuel gauge and gear indicator. For 1977 the gearing was revised, and the exhaust changed to a four-into-two with a silencer on either side. Due to slow sales the model was discontinued in 1978,[21] though Honda did later introduce smaller Hondamatic motorcycles (namely the CB400A, CM400A, and CM450A).[citation needed]

Nighthawk 750[edit]

1992 Honda Nighthawk 750

From 1982 through 2003, with the exception of several years, Honda produced a CB750 known as the Nighthawk 750. Early models were designated the CB750SC Nighthawk while later models were simply known as the Nighthawk 750.[25][26] The Nighthawk 750SC had a 4-stroke engine with a 5-speed manual transmission, chain drive and has front disc and rear drum brakes.

2007 CB750[edit]

2007 Honda CB750 Special

In 2007, Honda Japan announced the sale of a new CB750 very similar to the models sold in the 1970s. Announced as the CB750 Special Edition which is in the silver colors of the CB50 AMA racer of the 1970s, and the CB750, offered in three color schemes reminiscent of CB750s previously sold. As of August 2007, these bikes were intended only for release in Japan .[27]

Specifications[edit]

Model Engine displacement Fuel system Cam Valves per cylinder Power Torque Weight Drive
1969 CB750 Four[28][29] 736 cc (44.9 cu in)[29] 4 carburetors[29] SOHC[29] 2 67 bhp (50 kW) @ 8,000 rpm[10][29][30] 59.8 Nm (44.12 ft·lbf) @ 7,000 rpm[29] 218 kilograms (481 lb)[29] 5 Speed, Constant Mesh, Gearbox, Final Drive Chain[29]
1976–1978 CB750A[31] 736 cc (44.9 cu in) 4 carburetors SOHC 2 47 hp (35 kW) @ 7,500 rpm[21] 5.0 kg·m (49 N·m; 36 lbf·ft) @ 6,000 rpm[21] 262 kg (578 lb)[31] Two-speed w/torque converter, chain[21]
1978 CB750K[32] 748 cc (45.6 cu in) 4 carburetors DOHC 4 65 hp (48 kW) @ 9000 rpm 5.9 kg·m (58 N·m; 43 lbf·ft) @ 7000 rpm 231 kg (509 lb) Dry 5 Speed, Constant Mesh, Gearbox, Final Drive Chain
1979-1980 CB750F (RC04)[33] 748 cc (45.6 cu in) 4 carburetors[33] DOHC[33] 4 68 hp (51 kW) @ 9000 rpm[33] 5.9 kg·m (58 N·m; 43 lbf·ft) @ 8000 rpm[33] 228 kg (503 lb) Dry[33] 5 Speed, Constant Mesh, Gearbox, Final Drive Chain[33]
1980–1982 CB750C Custom[34] 748 cc (45.6 cu in) 4 carburetors[34] DOHC[34] 4 65 hp (48 kW) @9000 rpm[34] 5.9 kg·m (58 N·m; 43 lbf·ft) @ 7000 rpm[34] 236 kg (520 lb) dry
[34] ~252 kg (556 lb) wet[34]
5 Speed, Constant Mesh, Gearbox, Final Drive Chain[34]
1981 CB750F 748 cc (45.6 cu in) 4 carburetors DOHC 4 70 hp (52 kW)[citation needed] 536 lb (243 kg)[citation needed] Chain
1982–1983 CB750SC (Nighthawk) 749 cc (45.7 cu in) 4 carburetors DOHC 4 66.57 hp (49.64 kW) @ 9,000 rpm[citation needed] 41.54 lbf·ft (56.32 N·m) @ 7,500 rpm[citation needed] 573.5 lb (260.1 kg) wet[citation needed] 5-speed, chain[35][36] See also Honda CB700SC
1991–1993, 1995–2003 CB750 (Nighthawk) 747 cc (45.6 cu in) 4 Keihin 34 mm Constant Vacuum carburetors DOHC 4 75 hp (56 kW) @ 8,500 rpm[citation needed] 64 N·m (47 lbf·ft) @ 7,500 rpm[citation needed] 463 lb (210 kg)[citation needed] Chain
2007 CB750 747 cc (45.6 cu in) VENAC DOHC 4 74 hp (55 kW) @ 8,500 rpm[37] 64 N·m (47 lbf·ft) @ 7,500 rpm[37] 520 lb (240 kg)[37] Chain

References[edit]

  1. ^ a b c d e f g "Honda Dream CB750". 240 Landmarks of Japanese Automotive Technology. Society of Automotive Engineers of Japan, Inc. Retrieved 11 August 2013. Developed with the goal of giving riders greater power with better safety, the Dream CB750 featured Honda's first double cradle frame and the world's first hydraulic front disc brakes. 
  2. ^ a b Honda. "The Dream CB750 Four (Official history)". 
  3. ^ Honda CB750 – It Really Changed Everything, by Paul Crowe - "The Kneeslider" on 5/1/2008.
  4. ^ a b c Walker, Mick (2006), Motorcycle: Evolution, Design, Passion, JHU Press, p. 150, ISBN 0-8018-8530-2 
  5. ^ a b Landon Hall (July–August 2006). "Honda CB750 Four: A Classic for the Masses". Motorcycle Classics. Retrieved 17 November 2010. 
  6. ^ Frank, Aaron (2003), Honda Motorcycles, MotorBooks/MBI Publishing Company, p. 92, ISBN 0-7603-1077-7, retrieved 20 February 2010 
  7. ^ Motorcycle Hall of Fame, 1969 Honda CB750; The Year of the Super-bike, American Motorcyclist Association 
  8. ^ a b "The Dawn of the Superbike: Honda's Remarkable CB750", AMA Motorcycle Hall of Fame (American Motorcyclist Association), retrieved 20 February 2010 
  9. ^ "Greatest Motorbikes Ever". Discovery Channel. Archived from the original on 3 October 2009. 
  10. ^ a b c Statnekov, Daniel K.; Guggenheim Museum Staff (2003), "Honda CB750 Four", in Krens, Thomas; Drutt, Matthew, The Art of the Motorcycle, Harry N. Abrams, ISBN 0-8109-6912-2 
  11. ^ List of vehicles, National Motor Museum Trust, retrieved 19 October 2010 
  12. ^ Original Honda CB750 by John Wyatt - Bay View Books Ltd 1998
  13. ^ a b "Honda's Fabulous 750 Four; Honda Launches the Ultimate Weapon in One-Upmanship — a Magnificent, Musclebound, Racer for the Road", Cycle World, January 1969: 36–39, ISSN 0011-4286 
  14. ^ a b "Cycle Road Test: Honda 750cc Four", Cycle (magazine), August 1969: 33–39, 78–81 
  15. ^ Wilson, H. (1995), The Encyclopedia of the Motorcycle, Dorling Kindersley Limited, pp. 88–89, ISBN 0-7513-0206-6 
  16. ^ Employing an Idle Facility to Produce a Large Motorcycle, retrieved 25 August 2014 
  17. ^ Alexander, Jeffrey W. (2009), Japan's Motorcycle Wars: An Industry History, UBC Press, p. 206, ISBN 0-7748-1454-3, retrieved 5 April 2011 
  18. ^ Mick Duckworth (June 2004), "Classic Bike Dossier: Honda CB750" (PDF), Classic Bike, retrieved 15 January 2008 
  19. ^ Richard Backus (May–June 2010). "Honda CB750F Super Sport". Motorcycle Classics. Retrieved 21 May 2010. 
  20. ^ Classic Bike Glamorous and Glorious by Mick Duckworth June 2004 issue
  21. ^ a b c d e f g h Bacon, Roy (1996), Honda: The Early Classic Motorcycles : All the Singles, Twins and Fours, Including Production Racers and Gold Wing-1947 to 1977, Niton Publishing, pp. 110&ndsah;112, 185, 192, ISBN 1-85579-028-9 
  22. ^ a b Ker, Rod (2007), Classic Japanese Motorcycle Guide, Sparkford, UK: Haynes Publishing, p. 81, ISBN 1-84425-335-X 
  23. ^ a b Cycle World, September 1976
  24. ^ The Hondamatic Transmission, The Innovative Automatic Transmission: A Breakthrough in Original Thinking, 1968
  25. ^ Motorcycle Online Frugal Flyers Shootout
  26. ^ Motorcycle Online 2000 Valuebike Shootout
  27. ^ Honda Japan website
  28. ^ Honda Press 18 July 1969, Honda Dream 18 July 1969 CB750 FOUR.
  29. ^ a b c d e f g h Honda Dream CB750 Four History, The First Motorcycle to Offer Disc Brakes.
  30. ^ Brown, Roland (2005), The ultimate history of fast motorcycles, Bath, England: Parragon, pp. 114–115, ISBN 1-4054-5466-0 
  31. ^ a b Honda Press 1977, Honda EARA.
  32. ^ Honda Press Dec 1978, 1978 Honda CB750K.
  33. ^ a b c d e f g Honda Press June 1979, 1979 Honda CB750F Released June 23, 1979.
  34. ^ a b c d e f g h Honda Press May 20, 1980, 1980 Honda CB750C, CB750K, CB750F Press Release.
  35. ^ American Honda Motor Company (2000), Honda Motorcycle Identification Guide, 1959-2000, pp. 254–255, 262–263, 278, ISBN 0-9642491-1-1 
  36. ^ Falloon, Ian (2005), The Honda Story: Road and Racing Motorcycles from 1948 to the Present Day, Sparkford: Haynes, pp. 79–82, ISBN 1-85960-966-X 
  37. ^ a b c "Honda CB750 Specifications" (in JP). Honda Japan. Retrieved 9 May 2010. 

External links[edit]