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Honda CB550SC


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Honda CB550SC
Manufacturer Honda
Production 83
Engine 550cc
Sparkplug DPR8EA-9 '83
Battery YB12AL-A '83
Front Tire 100/90-19 '83
Rear Tire 130/90-16 '83
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The Honda CB550SC is a motorcycle produced by Honda in 1983.

This is a 550 Four performance cruiser, factory rated at 75 bhp at 9500 rpm, 36.5 lb.-ft. at 8000 rpm. Potent air-cooled, DOHC, link-plate cam chain, four valves per cylinder, offset rocker arms with hydraulic lash adjusters, plain bearing crankshaft, helical primary gears, hydraulic multi-plate wet clutch, six-speed transmission, shaft final drive.

This is the smaller version of Honda's 1983 inline Four, introduced in the Nighthawk 650 and Nighthawk 550 for 1983. The engines share crankcase castings, clutch, transmission and cylinder head. The 572cc 550 has lower primary gearing and the same 60mm bore as the 650; stroke is shorter; 50.6mm to 58mm. To work with the 50.6mm stroke, the 550 has shorter connecting rods, crankshaft throws and cylinders. The crankshaft, designed for the 572cc version, is lighter with 1mm smaller diameter journals; the cases are machined to fit.

The engine is designed to be compact. It is narrow, the alternator mounted behind the cylinders, overdriven off the crankshaft by a link-plate chain. It is short; the transmission shafts staggered vertically instead of laying one behind the other. It's also designed for low maintenance. The hydraulic lash adjuster automatically take up clearance between valve stems and rocker arms - meaning no valve adjustment is necessary - and pump down if the engine is over-revved, increasing clearance and reducing the chances of a mis-shift bending the valves. The transistorized electronic ignition is not adjustable, and has electronic advance. The hydraulic clutch, like hydraulic disc brakes, is self-adjusting.

Low maintenance doesn't mean low performance. The 550 has the same cams as the 650, and, used with the smaller engine, those cams are closer to the high-performance grinds sold by aftermarket engine builders than are most stock camshafts. The four Keihin CV carbs have oval throats, 26.8mm at the venturi, 30mm at the throttle plate, with lightweight throttle slides and thin diaphragms for instant throttle response. Combine the cams and the carbs with the lighter crankshaft and you've got a quick-revving, free-winding 550 that feels faster than anything in the class.

It feels fast because it has a big jump in horsepower and acceleration at 7000 rpm, gaining engine speed from there at an astonishing rate right up to the 10,000 rpm redline. It pulls well from 4000 rpm, well enough to leave lights quickly and have fun gaining speed, but then there's that kick at 7000 when the Nighthawk comes on the cams, and off it goes. There's nothing to distract the rider from that magic rush of the tach needle toward redline, since the rubber-mounted engine is one of the smoothest ever put in a motorcycle. That glass-smoothness adds an eerie quality to the soaring tach and the kick-in-the-pants acceleration.

Slam the 550 into second gear at redline and the front wheel comes up and floats a foot or two off the ground, slowly settling as the bike continues to gain speed. Keep the Nighthawk near the redline, shifting quickly, and a rider on anything short of a sporting 1100 will have to work to keep up or pass. Street impressions send a strong message, that this is the most potent, quickest, fastest 550 around.

A trip to the dragstrip brought some surprises. The Honda Nighthawk isn't the fastest 550, with a best pass of 12.64 seconds and 102.27 mph. That's about as fast as a 1982 Kawasaki GPz550 and not as fast as a 1983 Suzuki GS550E, even though the Nighthawk feels quicker than both.

The Nighthawk's tall sixth gear is made for highway cruising at a leisurely pace, bringing engine rpm at 60 mph down to 4400 rpm from fifth gear's 5200 rpm.


1983


The Honda Nighthawk 550, designated CB550SC'83, was sold in 1983. Two colors were available: Candy Presto Red and Black. It had a chrome rectangular headlight and a 4-into-2 exhaust system.

  • Engine: Completely new compact 572cc, DOHC inline four-cylinder
  • Power: 64 horsepower
  • Valve train: Hydraulic Valve Adjuster system, 16 valves
  • Transmission: 6-speed
  • Drive: Shaft
  • Clutch: Self-adjusting Hydraulic
  • Suspension: Air-adjustable front forks with integrated fork brace
  • Oil: Oil cooler
  • Wheelbase: 1440mm (56.7 in)
  • Seat height: 777 mm(31.1 in.)
  • Fuel capacity: 12 liters (3.2 gal.)
  • Weight: 191 kg (421.1 lb)
  • The serial number began JH2PC0901DM000023

1984

1984 Honda Nighthawk 550


The Honda Nighthawk 550, designated CB550SC'84, was sold in 1984.

  • Engine: Completely new compact 572cc, DOHC inline four-cylinder
  • Power: 64 horsepower
  • Valve train: Hydraulic Valve Adjuster system, 16 valves
  • Transmission: 6-speed (5-speed plus overdrive sixth)
  • Drive: Shaft
  • Clutch: Self-adjusting Hydraulic
  • Suspension: Air-adjustable front forks with integrated fork brace
  • Oil: Oil cooler
  • Wheelbase: 1440mm (56.7 in)
  • Seat height: 790 mm(31.1 in.)
  • Fuel capacity: 12 liters (3.2 gal.)
  • Weight: 190 kg (418.8 lb)
  • The serial number began JH2PC0901EM000023


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