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Honda Nighthawk 750

The Honda Nighthawk 750 is the grandson of the most significant motorcycle ever made-- the 1970 Honda CB750.
The Nighthawk stays true to its heritage: Air cooled 750cc inline-four engine, double-cradle frame, single disk front and drum rear brake, and chain drive. The differences are ones of evolutionary refinement. It has hydraulic valve adjusters for zero-maintenance valves. Electronic ingition means there's no more fiddling with the idle speed. The engine's width is narrower as Honda has relocated the alternator behind the cylinders. They also added a small oil cooler to supplement the air cooling. Wheels are cast aluminum rather than spoked. The exhaust is a more modern four-into-two variety.

This is a do-it-all bike. It doesn't do anything with exquisite skill but it does everything reasonably well and for that it deserves a lot of credit. In stock form it's a nimble commuter. Attach a windscreen and luggage and you've got a lightweight touring bike. It's fun to drive too. Though it's no racer it is quick enough and the handling is reasonable and responsive. It feels lighter than it really is. The Nighthawk's reliability is legendary. It demands as little attention as any motorcycle and maintenance is cheap. Change the oil regularly and it will run forever.
(The above taken from David's Motorcycle Reviews)

Unfortunately the last production year for the Nighthawk 750 was 2003.

Specs & Performance

1982 CB750SC
MSRP -- $3098
PERFORMANCE

Standing Start 1/4 mile

13.109 [email-masked] mph

Engine rpm @ 60 mph, top gear

4344

Average fuel consumption rate

42.2 mpg (17.9 km/l

Cruising range, main / reserve

139 / 55 miles

Load capacity (GVWR less curb weight)

371.5 lbs. (168.5 kg)

Maximum speed in gears @ engine redline

(1) 49.9 (2) 70.7 (3) 90.9 (4) 109.0 (5) 131.2

ENGINE

Type

4 Stroke, transverse four cylinder with two overhead camshafts, chain-driven

Bore and stroke

62.0 x 62.0 mm (2.44 x 2.44 in.)

Piston displacement

749cc (45.7 cu. in.)

Compression ratio

9.0:1

Carburetion

4 Keihin 30mm constant-vacuum with accelerator pump.

Exhaust system

Four into four

Ignition

Battery-powered, inductive, magnetically triggered and electronically advanced.

Air filtration

Paper element disposable

Oil filtration

Paper element disposable

Oil capacity

4.8 qts (4.5 liters)

65.57 @ 9000

41.54 ft. lbs @ 7500

TRANSMISSION

Type

Five-speed, constant-mesh, multi-plate wet clutch

Primary drive

Hy-Vo chain and spur gears, 2.38:1

Final drive

# 530 sealed O-ring chain, 2.39:1

Gear ratios, overall

(1) 14.40 (2) 10.17 (3) 7.91 (4) 6.59 (5) 5.48

CHASSIS

Type

Dual downtube, full-cradle, mild steel frame

Suspension, front

Leading-axle coil / air spring fork with anti-dive yielding 154mm (6.1 in.) travel

Suspension, rear

Swing arm, (2) VHD (Variable Hydraulic Damping) shocks with five spring preload adjustments yielding 93mm (3.7 in.) travel

Wheelbase

60.8 in. (1545mm)

Rake / trail

29.5 degrees / 4.7 in. (120mm)

Brake, front

Hydraulic, dual disc, (2) 276mm (10.87 in.) rotors with dual-piston calipers

Brake, rear

Rod-actuated drum

Wheel, front

Cast, 2.50 x 18

Wheel, rear

Cast, 3.00 x 16

Tire, front

MT 120/90 x 18 Dunlop Qualifier F11

Tire, rear

M140 x 16 Dunlop Qualifier K127

Seat height

31.2 in. (792mm)

Ground clearance

6.4 in. (163mm)

Fuel capacity, main / reserve

3.3 / 1.3 gal. (12.5 / 4.9 liters)

Curb weight, full tank

573.5 lbs. (260.1 kg)

Test weight

733.5 lbs. (332.7 kg)

ELECTRICAL

Power source

Three-phase AC generator

Charge control

Solid state

Headlight beams, high / low

60 / 55 watts

Tail / stop lights

(2) 8 / 27 watts

Battery

12 V 14 AH

INSTRUMENTS

Includes:

Speedometer, odometer, tripmeter, tachometer, fuel gauge. Indicators for low oil pressure, neutral, high beam and turn indicators

Speedometer error

30mph indicated, actual 29.43
60mph indicated, actual 58.74

91-97 Nighthawk 750
Specifications

Dimensions

Overall length

86.0 in.

Wheel base

59.3 in.

Overall width

31.5 in.

Ground clearance

5.5 in.

Overall height

44.7 in.

Dry weight

463 lb.

Seat height

30.7 in.

Curb weight

498 lb.

Footpeg height

12.6 in.

Max weight capacity

364 lb.

Frame

Frame type

Double cradle

Fuel tank capacity

4.76 US gal (18 liters)

Front suspension

Telescopic fork

Reserve capacity

0.79 US gal. (3.0 liters)

Front wheel travel

5.5 in.

Front Brake

Hydraulic disc brake

Rear suspension

Swingarm

Rear brake

drum

Rear wheel travel

4.3 in.

Caster angle

29 °

Rear damper

Dual spring & shock

Trail length

4.6 in.

Engine

Bore & stroke

2.6 x 2.1 in. (67 x 53 mm)

Lubrication system

Forced pressure & set sump

Displacement

45.6 cu-in. (747cc)

Oil pump type

Trochoid

Compression ratio

9.3:1

Cooling system

Air cooled

Valve train

DOHC chaindrive with rocker arm

Air filtration

Paper filter

Intake valve opens at

0 ° BTDC

Oil filter

Paper filter (Fram PH6017A)

Intake valve closes

35 ° ABDC

Engine weight

179.2 lb.

Exhaust valve opens

30 ° BBDC

Firing order

1-2-4-3

Exhaust valve closes

-5 ° ATDC

Cylinder arrangement

Inline 4 L1-2-3-4R

Carburetor

Carburetor type

4 CV (constant vacuum)

Throttle bore

1.3 in. (34mm)

Drive Train

Clutch system

Multi-plate wet

Gear ratio 1st

3.00:1 (42/14)

Clutch operation

manual

Gear ratio 2nd

2.056:1 (37/18)

Transmission

5 speed

Gear ratio 3rd

1.545:1 (34/22)

Primary reduction

1.780 (73/41)

Gear ratio 4th

1.240:1 (31/25)

Secondary/third reduction

N/A

Gear ratio 5th

1.074:1 (29/27)

Final reduction

2.533 (38/15)

Gearshift pattern

1-N-2-3-4-5

Oil

Engine Oil Capacity at draining

2.8 U.S. quarts (2.7 liters)

Recommended Oil for various temperature ranges:

Engine Oil Capacity with filter change

3.1 U.S. quarts (3.0 liters)

32 ° F to >115 ° F

SAE 20W-50

Oil pressure @176 ° F

90 psi @ 6,000 rpm

32 ° F to >110 °F

SAE 20W-40

Recommended Oil

Honda 4-stroke oil or equivalent. API SF or SG, SAE 10W-40

5 ° F to 110 ° F

SAE 10W-40

5 ° F to 90 ° F

SAE 10W -30

Wheels/Tires/Chain

Min front tire tread depth

0.06 in. (1.5mm)

Drive chain slack

3/4 in. to 1-3/16 in. (20-30mm)

Min rear tire tread depth

0.08 in. (2.0mm)

Drive chain size/link:

Cold Tire pressure (up to 200 lb. load)

front 33 psi
rear 33 psi

DID chain

DID 525 V9/110

Cold Tire pressure (up to max weight capacity)

front 33 psi
rear 41 psi

RK chain

RK 525 SM4/110

Tire type, front

Dunlop K505F

Front tire size

110/80-18 58H

Tire type, rear

Dunlop K505

Rear tire size

140/70-17 66H

Electrical

Alternator charging coil

0.4 - 0.6 ohms

Front turn signal/running light

12 V 32/3 CP

Alternator field coil

2.1 - 2.6 ohms

Rear turn signal/light

12 V 32 CP

Regulator / rectifier regulated voltage/amperage

13.0 - 15.0 V/below 0.5A/2,000 rpm

Instrument lights

3 x 12 V 1.7 W

Battery capacity

12V - 14 Ah

Oil warning light

12 V 3 W

Normal Batt charging rate

1.4 A / 10h

Side stand warning light

12 V 3 W

Main fuse

30 A

High beam indicator light

12 V 3 W

Other fuses

2 x 10 A, 1 x 15 A

Turn signal indicator light

12 V 3.4 W

Headlight (high/low beam)

12 V 60/55 W

Neutral indicator light

12 V 3 W

Tail / brake light

12 V 3/32 CP

Ignition System

Standard NGK

DPR 8EA-9

Advance Stop

33 ° / 4,000 rpm

High speed NGK

DPR 9EA-9

Full advance

33 ° / 4,000 rpm

Standard Nippondenso

X24EPR-U9

Ignition coil resistance:

High speed Nippondenso

X27EPR-U9

primary at 68 ° F

2.6 - 3.2 ohms

Spark Plug gap

0.03 - 0.04 in. (0.8 - 0.9mm)

secondary with plug cap

18 - 22 kohms

Ignition timing "F" mark

10 ° BTDC

secondary without plug cap

13 - 17 kohms

Advance Start

10 ° / 1,500 rpm

Ign. pulse gen. resistance

297 - 363 ohms

Specifications for 2003 Honda Nighthawk 750

2003 750 Nighthawk

ENGINE
Engine Type 747cc air-cooled inline four-cylinder/ Bore and Stroke 67.0mm x 53.0mm/ Compression Ratio 9.3:1/ Valve Train DOHC; four valves per cylinder / Carburetion Four 34mm CV/ Ignition CDI

DRIVE TRAIN
Transmission Five-speed/ Final Drive O-ring-sealed chain/

CHASSIS / SUSPENSION / BRAKES
Front Suspension 41mm fork; 5.5-inch travel/ Rear Suspension Dual rear shocks with five-position spring-preload adjustability; 4.3-inch travel/ Front Brake Single disc with twin-piston caliper/ Rear Brake Drum/ Front Tire 110/80-18/ Rear Tire 140/70-17/

DIMENSIONS
Wheelbase 59.3 inches/ Seat Height 30.9 inches/ Dry Weight 463.0 pounds/ Fuel Capacity 4.8 gallons, including 0.8-gallon reserve/