Honda CB750

Honda CB750

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	51 kW (68 hp) @ 8500 rpm (1969)[3] 50 kW (67 hp) @ 8000 rpm (DIN)[1][4]
Torque	44 lbf·ft (60 N·m) @ 7000 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	94 mm (3.7 in)
Wheelbase	1,460 mm (57.3 in)
Dimensions	L: 2,200 mm (85 in) W: 890 mm (35 in) H: 1,100 mm (44 in)
Seat height	790 mm (31 in)
Weight	218 kg (481 lb)[1] (dry) 233 kg (513 lb)[5] (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)[6]

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][7]

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;^[8][9] was named in the Discovery Channel's "Greatest Motorbikes Ever;"^[10] was in The Art of the Motorcycle exhibition,^[11] and is in the UK National Motor Museum.^[12] 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."^[6][11]

History

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 Cub 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 US dealers and understood the opportunity for a larger bike.

Early racing

In 1967 American Honda's service manager Bob Hansen^[13][14] 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, and restricted overhead-valve engines to 500 cc whilst allowing the side-valve Harley Davidsons to compete with 750 cc engines.^[15] 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 Soichiro Honda that he should build a 'King of Motorcycles' and the CB750 appeared at the Tokyo Show in November, 1968^[16] and was publicly launched in UK at the Brighton, England motorcycle show held at the Metropole Hotel exhibition centre during April 1969,^[16][17] with an earlier press-launch at Honda's London headquarters,^[16][17] the pre-production versions appearing with a high and very wide handlebar intended for the US market.^[16]

The AMA Competition Committee recognised the need for more variation of racing motorcycle and changed the rules from 1970, by standardizing a full 750 cc displacement for all engines regardless of valve location or number of cylinders, enabling Triumph and BSA to field their 750 cc triples instead of the 500 cc Triumph Daytona twins.^[15]

Dick Mann's Daytona-winning CR750 on display at Le Musée Auto Moto Vélo, a transportation Museum in Châtellerault, France

The Honda factory responded by producing four works-racer CR750s, a racing version of the production CB750, ridden by UK-based Ralph Bryans, Tommy Robb and Bill Smith under the supervision of Mr Nakamura, and a fourth machine under Hansen ridden by Dick Mann. The three Japanese-prepared machines all failed during the race with Mann just holding on to win by a few seconds with a failing engine.^[15]

Hansen's race team's historic victory at the March, 1970 Daytona 200 with Dick Mann riding a tall-geared CR750 to victory^[2][18] preceded the June, 1970 Isle of Man TT races when two 'official' Honda CB750s were entered, again ridden by Irishman Tommy Robb partnered in the team by experienced English racer John Cooper. The machines were entered into the 750 cc Production Class, a category for road-based machines allowing a limited number of strictly-controlled modifications. They finished in eighth and ninth places.^[19] Cooper was interviewed in UK monthly magazine Motorcycle Mechanics, stating both riders were unhappy with their poor-handling Hondas, and that he would not ride in the next year's race "unless the bikes have been greatly improved".^[20]

In 1973, Japanese rider Morio Sumiya finished in sixth place in the Daytona 200-Mile race on a factory 750.^[21]

Production and reception

Under development for a year,^[22] 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 brake, along with the introductory price of US$1,495^[23] (US$9,647 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.^[23] 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.^[22]

The CB750 was the first modern four-cylinder machine from a mainstream manufacturer,^[24] and the term superbike was coined to describe it.^[4][9] 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^[25] – unsure of the bike's reception. The bike remained in the Honda line up for ten years, with a production total over 400,000.^[26]

Models

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^[27]

• 1969 CB750 (6 June), CB750K or CB750K0 (date unknown)
• 1970 CB750K1 (21 September)
• 1971 CB750K2 (US 1 March)
• 1973 CB750K3 (US-only 1 February. K2 elsewhere)
• 1974 CB750K4 (US/Japan-only, K2 elsewhere)
• 1975 CB750K5 (US-only, K2/K4 elsewhere), CB750FO, CB750A (Canada-only)^[28] 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^[29]

DOHC

• 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
• 1984-1986 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

CB750A

Also called	Hondamatic
Production	1976–1978[30]
Engine	736.6 cc (44.95 cu in) inline-four, SOHC air-cooled
Bore / stroke	61.0 mm × 63.0 mm (2.40 in × 2.48 in)
Compression ratio	7.7:1
Top speed	156 km/h (97 mph)[31]
Power	35 kW (47 hp) @ 7500 rpm[30]
Torque	5.0 kg·m (49 N·m; 36 lbf·ft) @ 6000 rpm[30]
Ignition type	Coil
Transmission	2-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"
Rake, trail	28°, 110 mm (4.5 in)
Wheelbase	1,470 mm (58.0 in)
Dimensions	L: 2,260 mm (89.0 in) W: 800 mm (31.5 in)
Seat height	840 mm (33.0 in)
Weight	262 kg (578 lb) (claimed)[32] (dry) 259 kg (572 lb)[31] (wet)
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 2-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).^[30][33] 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).^[31]

The CB750A was sold in the North American market only.^[33] 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,^[31][34] 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, 35.0 kW (47.0 hp). 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,^[30] though Honda did later introduce smaller Hondamatic motorcycles (namely the CB400A, CM400A,^[35] and CM450A).^[36] Cycle World tested the 1976 CB750A's top speed at 156 km/h (97 mph), with a 0 to 60 mph (0 to 97 km/h) time of 10.0 seconds and a standing 0 to ¹⁄₄ mile (0.00 to 0.40 km) time of 15.90 seconds at 138.95 km/h (86.34 mph).^[31] Braking from 60 to 0 mph (97 to 0 km/h) was 39 m (129 ft).^[31]

Nighthawk 750

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.^[37][38] 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

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 that was in the silver colors of the CB50 AMA racer of the 1970s and the CB750, it was offered in three color schemes reminiscent of CB750s previously sold. As of August 2007, these bikes were intended only for release in Japan.^[39]

Specifications

Model	Engine displacement	Fuel system	Cam	Valves per cylinder	Power	Torque	Weight	Drive
1969 CB750 Four[40][41]	736 cc (44.9 cu in)[41]	4 carburetors[41]	SOHC[41]	2	67 bhp (50 kW) @ 8000 rpm[11][41][42]	59.8 N·m (44.1 lbf·ft) @ 7000 rpm[41]	218 kg (481 lb) (dry)[41]	5-Speed, Constant Mesh, Gearbox, Final Drive Chain[41]
1976–1978 CB750A[32]	736 cc (44.9 cu in)	4 carburetors	SOHC	2	35 kW (47 hp) @ 7500 rpm[30]	5.0 kg (11.0 lb) @ 6000 rpm[30]	262 kg (578 lb) (claimed dry)[32] 259 kg (572 lb) (wet) [31]	2-speed w/torque converter, chain[30]
1978 CB750K[43]	748 cc (45.6 cu in)	4 carburetors	DOHC	4	59 kW (79 hp) @ 9000 rpm	5.9 kg (13 lb) @ 7000 rpm	231 kg (509 lb) (dry)	5-Speed, Constant Mesh, Gearbox, Final Drive Chain
1979–1980 CB750F (RC04)[44]	748 cc (45.6 cu in)	4 carburetors[44]	DOHC[44]	4	59 kW (79 hp) @ 9000 rpm[44]	5.9 kg (13 lb) @ 8000 rpm[44]	228 kg (503 lb) Dry[44]	5-Speed, Constant Mesh, Gearbox, Final Drive Chain[44]
1980–1982 CB750C Custom[45]	748 cc (45.6 cu in)	4 carburetors[45]	DOHC[45]	4	59 kW (79 hp) @ 9000 rpm[45]	5.9 kg (13 lb) @ 7000 rpm[45]	236 kg (520 lb) dry [45] ~252 kg (556 lb) wet[45]	5-Speed, Constant Mesh, Gearbox, Final Drive Chain[45]
1981 CB750F	748 cc (45.6 cu in)	4 carburetors	DOHC	4	59 kW (79 hp)		243 kg (536 lb)	Chain
1982–1983 CB750SC (Nighthawk)	749 cc (45.7 cu in)	4 carburetors	DOHC	4	49.64 kW (66.57 hp) @ 9000 rpm	41.54 lbf·ft (56.32 N·m) @ 7500 rpm	260.1 kg (573.5 lb) wet	5-Speed, Chain[46][47] 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	56 kW (75 hp) @ 8500 rpm	64 N·m (47 lbf·ft) @ 7500 rpm	210 kg (463 lb)	Chain
2007 CB750	747 cc (45.6 cu in)	VENAC	DOHC	4	55 kW (74 hp) @ 8500 rpm[48]	64 N·m (47 lbf·ft) @ 7500 rpm[48]	240 kg (520 lb)[48]	Chain

References

1. "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. Honda. "The Dream CB750 Four (Official history)".
3. Honda CB750 – It Really Changed Everything, by Paul Crowe - "The Kneeslider" on 5/1/2008.
4. Walker, Mick (2006), Motorcycle: Evolution, Design, Passion, JHU Press, p. 150, ISBN 0-8018-8530-2
5. "Cycle World Road Test: Honda CB750", Cycle World, vol. 8 no. 8, August 1970, pp. 44–51
6. Landon Hall (July–August 2006). "Honda CB750 Four: A Classic for the Masses". Motorcycle Classics. Retrieved 17 November 2010.
7. Frank, Aaron (2003), Honda Motorcycles, MotorBooks/MBI Publishing Company, p. 92, ISBN 0-7603-1077-7, retrieved 20 February 2010
8. Motorcycle Hall of Fame, 1969 Honda CB750; The Year of the Super-bike, American Motorcyclist Association
9. "The Dawn of the Superbike: Honda's Remarkable CB750", AMA Motorcycle Hall of Fame (American Motorcyclist Association), retrieved 20 February 2010
10. "Greatest Motorbikes Ever". Discovery Channel. Archived from the original on 3 October 2009.
11. 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
12. List of vehicles, National Motor Museum Trust, retrieved 19 October 2010
13. Girdler, Alan. Bob Hansen, 1919–2013 A long and rewarding life. Cycle World
14. Bob Hansen at the Motorcycle Hall of Fame
15. Mann and machine, Motorcyclist online Retrieved 13 June 2015
16. Motorcycle Sport, UK monthly magazine, April 1969, pp. Cover, 121, 132–133. Honda's 750-4 arrives. "The wide, sweeping handlebars on the machines shown at Brighton are fitted in the US market, but before deciding on whether or not these will be the ones for this country some discussion will take place between Honda UK and dealers and prospective owners". Accessed 15 June 2015
17. Motorcycle Mechanics, May 1969, Showtime - 6-page-special. pp. Cover, 38–39, Honda's Four. "MM takes a close look at the new 4-pot Honda 750". Accessed 15 June 2015
18. Original Honda CB750 by John Wyatt - Bay View Books Ltd 1998
19. Isle of Man TT Races official site 1970 Production 750cc Results Retrieved 13 June 2015
20. Motorcycle Mechanics, December 1970, pp.36-37 John Cooper interview by Charles Deane (editor). Accessed 13 June 2015
21. Honda WorldWide, Honda Motor Co., Ltd official site Retrieved 20 June 2015
22. "Honda's Fabulous 750 Four; Honda Launches the Ultimate Weapon in One-Upmanship — a Magnificent, Musclebound, Racer for the Road", Cycle World, January 1969, pp. 36–39, ISSN 0011-4286
23. "Cycle Road Test: Honda 750cc Four", Cycle (magazine), August 1969, pp. 33–39, 78–81
24. Wilson, H. (1995), The Encyclopedia of the Motorcycle, Dorling Kindersley Limited, pp. 88–89, ISBN 0-7513-0206-6
25. Employing an Idle Facility to Produce a Large Motorcycle, retrieved 25 August 2014
26. Alexander, Jeffrey W. (2009), Japan's Motorcycle Wars: An Industry History, UBC Press, p. 206, ISBN 0-7748-1454-3, retrieved 5 April 2011
27. Mick Duckworth (June 2004), "Classic Bike Dossier: Honda CB750" (PDF), Classic Bike, retrieved 15 January 2008
28. Richard Backus (May–June 2010). "Honda CB750F Super Sport". Motorcycle Classics. Retrieved 21 May 2010.
29. Classic Bike Glamorous and Glorious by Mick Duckworth June 2004 issue
30. 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, 112, 185, 192, ISBN 1-85579-028-9
31. "Honda's CB750F Stick versus the CB750A Automatic", Cycle World (Newport Beach, California: Hachette Filipacchi Media U.S.), vol. 15 no. 9, September 1976, pp. 60–65, ISSN 0011-4286
32. Honda Press 1977, Honda EARA.
33. Ker, Rod (2007), Classic Japanese Motorcycle Guide, Sparkford, UK: Haynes Publishing, p. 81, ISBN 1-84425-335-X
34. The Hondamatic Transmission, The Innovative Automatic Transmission: A Breakthrough in Original Thinking, 1968
35. Honda Shop Manual CB/CM400's. Honda Motor Co. Ltd. December 1980. p. 1.
36. Honda Shop Manual CB/CM450's. American Honda Motor Co. 1984. p. 4.
37. Andy Saunders. "Frugal Flyers: A Six-Bike Shoot Out". motorcycle.com.
38. MO Staff. "2000 Valuebike Shootout". motorcycle.com.
39. Honda Japan website
40. Honda Press 18 July 1969, Honda Dream 18 July 1969 CB750 FOUR.
41. Honda Dream CB750 Four History, The First Motorcycle to Offer Disc Brakes.
42. Brown, Roland (2005), The ultimate history of fast motorcycles, Bath, England: Parragon, pp. 114–115, ISBN 1-4054-5466-0
43. Honda Press Dec 1978, 1978 Honda CB750K.
44. Honda Press June 1979, 1979 Honda CB750F Released June 23, 1979.
45. Honda Press May 20, 1980, 1980 Honda CB750C, CB750K, CB750F Press Release.
46. American Honda Motor Company (2000), Honda Motorcycle Identification Guide, 1959-2000, pp. 254–255, 262–263, 278, ISBN 0-9642491-1-1
47. 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
48. "Honda CB750 Specifications" (in Japanese). Honda Japan. Retrieved 9 May 2010.

External links

• The Dream CB750 Four (Official history)
• CB750 images at the 1969 Brighton Motorcycle Show
• Boehm, Mitch (July 29, 2014), "The Honda CB750 Sandcast Prototype; In early 1969, Honda's guys hand-built four CB prototypes. Three are gone. This is the story of the fourth", Motorcyclist