Engineering:Honda NT650

Short description: Motorcycle

Honda Hawk GT

1988 Honda Hawk GT
Manufacturer	Honda
Also called	NT650, Bros, RC31
Production	1988–1992
Class	Naked bike
Engine	647 cc (39.5 cu in), four-stroke, 52° V-twin
Bore / stroke	79.0 mm x 66.0 mm
Compression ratio	9.4:1
Top speed	180 km/h (110 mph)
Power	43 kW (58 hp) (claimed) 28.0 kW (37.5 hp) (rear wheel)
Torque	42 N⋅m (31 lb⋅ft) (rear wheel)
Transmission	5-speed, manual, chain
Suspension	F: Showa 41mm non-adjustable fork, 140 mm (5.5 in) wheel travel R: Showa shock with adjustable preload, 120 mm (4.7 in) wheel travel
Brakes	F: Dual-piston, 316 mm (12.4 in) disc R: Single-piston, 240 mm (9.4 in) disc
Tires	F: 110/80–17 R: 150/70–17
Rake, trail	28.0º, 120 mm (4.7 in)
Wheelbase	1,430 mm (56.3 in)
Seat height	30.6 in (780 mm)
Weight	181.0 kg (399.1 lb) (claimed) (dry) 187 kg (412 lb) (wet)
Fuel capacity	12 L (2.6 imp gal; 3.2 US gal)
Oil capacity	2.8 L (3.0 US qt)

The Honda Hawk GT (NT650) motorcycle was designated as model RC31 and was designed by Toshiaki Kishi, and was the second Honda with "Pro-Arm" suspension bike after the RC30 VFR750R. The RC model designation is for bikes up to 750 cc, though the Honda Pacific Coast (PC800) has an engine of more than 750 cc and a model designation of RC34.

650 cc Honda Hawk GT

The Hawk GT is one of the first modern naked bikes along with the Yamaha SRX, which were both released several years before the Ducati Monster and eventually the Suzuki SV650. The Hawk GT is often described as a cult bike.

North American model

The US model NT650, Hawk GT 647, RC31 was introduced in 1988 and produced through 1991. It has an aluminium box frame with the separate rear frame bolted on, and a chain-drive, single-sided swingarm.

Priced above other entry-level models and only slightly below many 600 cc sport bikes, the Hawk GT did not sell well in American markets.

There are only very minor changes between the 1988 model year and the 1989-1991 model years. In 1989, the front suspension damper rods were changed to have only two (rather than four for the 1988) holes. The front brake calipers were also changed to have screw-on covers over the mounting pins. In 1991, the oil lines were run internally through the engine, rather than externally. The Canadian model was identical to the US model except for the colors. In the US, the 1988 model was offered in Tempest Gray and Tanzanite Blue. In subsequent years, Bright Red only was offered in the US.

The 1988 model had a wet weight of 187 kg (412 lb). The 650 cc engine had a claimed output of 43 kW (58 hp) @ 5000 rpm.

European model

A cousin to the Hawk GT, the NTV 600 'Revere' was available in Europe from 1988 to 1992. It had an integrated steel frame, larger fuel tank (19 litres or 4.2 imperial gallons), a lower and stubbier silencer, shaft drive, single-sided alloy swinging arm at rear with adjustable monoshock and a centre stand. It was launched a 'gentleman's' motorcycle but was seen as expensive for what was on offer.

The 600 Revere was replaced in 1993 by the bored-out NTV650 (the Revere name being dropped in the u.k), with a cheaper specification (including tubular handlebars instead of alloy bars, cheaper instruments and horns, some supplied without a centre stand), and continued with the 'stubby' silencer until '95 and later models got a full length silencer to comply with updated noise regs. The price was reduced compared to the Revere, and this later model sold better.

The NTV650 was replaced in 1998 by the Spanish built NT650V Deauville, a much heavier fully-faired model with integral small panniers and a steel double-sided swinging arm.

Japan model

400 cc Honda Bros

Named the Bros in Japan, because the two different engine displacement versions conceived together as 'brothers', the Bros came in 400 and 650 cc (24 and 40 cu in) versions, with the Bros 400 being designated NC25. After Honda stopped exporting the Hawk in 1992, they continued the Bros in Japan for one more year. A close ratio gear box (which drops into the Hawk), different wheels, and lower clip-ons were the major changes. A Motor Cycle News review said the Bros 400 is "heavy, underpowered and outdated, ... but surprisingly nice to ride – they’re well balanced, steer well and the engine is flexible, torquey and characterful given its 33bhp output. The Bros version is chain driven instead of using a shaft drive, lightening the unspring weight of the bike considerably. The Bros has a comfy, semi-upright café racer riding position."

References

• "The 10 best motorcycles of 1988 (evaluation)", Cycle World 27 (10): 27, October 1988 
• "1989 Honda NT650 Hawk GT; The bike that changed my life", Motorcyclist: 15, October 2009, http://www.motorcyclistonline.com/newsandupdates/122_0910_1989_honda_nt650_hawk_gt/index.html 
• Assoc, American Motorcyclist (February 1996), "Cult Bikes; A legend in your own mind?", American Motorcyclist: 23–26, https://books.google.com/books?id=O_YDAAAAMBAJ&pg=PT23 
• Edwards, David (June 1988), "The view from the real world (3 Cycle World readers try out the Honda Hawk GT)", Cycle World 27 (6): 40–42 
• "Honda CB-1, 1989-1990", Motorcyclist: 95, December 2000 
• Girdler, Allan (July 1990), "Standard time (motorcycles) (evaluation)", Cycle World 29 (7): 26 
• Miles, Matthew (September 1991), "Going British on a budget (customizing a Honda Hawk GT 647 motorcycle)", Cycle World 30 (9): 54