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History
The following paragraphs describe, in Honda's own words1, the design philosophy [we think...] behind the NR:
Object of Development
Unlike conventional sports motorcycles, that used to pursue exclusively a dynamic run, NR750 was born as a new road sports realizing a perfect balance between the antagonistic characteristics of dynamic power feeling and elegance, with the "I want to feel the emotion of riding a motorcycle!" development concept applicable not only when you are giving it a dynamic run, but also when you are enjoying the gliding feeling of the controls and when you are performing ordinary throttle work.
Output Characteristics
Featuring oval pistons with non-round shape challenging the "round shape" common sense of pistons, that seemed to be perennially valid ever since the invention of the reciprocating internal combustion engine, its performance has improved by a leap, and it realizes easy handling, high-ceiling performance and crispy output characteristics that can be expressed as "Dynamism & Elegance", by giving full play to the merits of the oval piston engine.
Rider Comfort
A comfortable and thrilling riding space is realized from ordinary run in street areas to high speed cruising on highways.
Design of a New Road Sports Bike
An original atmosphere, individuality and sense of value was created by selecting "Assertion of its Presence" as a theme, for the NR750 to stand out for its striking presence even when surrounded by hundreds of other motorcycles.
Running Characteristics
An elegant feeling of quality absent in conventional motorcycles is realized by surpassing the old concept of absolute performance expressed in terms of mere dynamism. In other words, a compromise is found between technical data and feeling by introducing the concept of elegance in addition to the old trend based exclusively on performance and technical data pursuing exclusively dynamism. Thus, every behavioral detail of the motorcycle body is characterized by moderation, and running characteristics expressed in terms of "Enjoying and Feeling Pleasure and Satisfaction with the Controls" when running straight stretches, negotiating curves and braking at every speed range are realized as an extension of that moderation.
Aero-management
The fairing shape was designed after repeated computer analysis and wind tunnel experiements, for ground-gripping feeling of the tiresto remain upchanged up to the high-speed range, by taking into consideration not only the reduction of the wind pressure working on the upper part of the rider's body but also the subtle changes in the wind when the motorcyle changes its direction. Aerodynamic performance characterized by "zero" total lift force is realized as a result.
Visibility, Noticeability (Preventative Safety)
The presence of motorcycles is not so noticeable comparing with cars because they have smaller surface area. Making motorcycles noticeable within the road traffic is an important theme. Improved visibility and noticeability are realized through the adoption of flourescent red-painted looks with brightness surpassing by far the conventional colors, as well as a projector-unified headlight securing sufficient front illumination without glaring other vehicles.
Models
There was just the one model, the "N", built at Honda's Hamamatsu factory during 1992. French-spec models were sufficiently different from the others to require a different vehicle description code (RC41 vs. RC40), and in order to achieve the French-market 100bhp limitation, RC41s feature different profile camshafts and different PGM-FI units. Swiss and Austrian models featured additional emissions control equipment, notably an air injection system similar to (but not so named) the PAIR system found on many other Hondas. Finally, UK-spec models also featured a button to change the LCD display from MPH to KPH (presumably for those long, continental sport-touring trips...)
The following table details the serial, engine and throttle body numbers for the [~300-unit]2 NR production run:
| Year | Code | Region | Beg. Engine #s | End. Engine #s | Beg. Frame #s | End. Frame #s | Throttle Body ID #s |
| 1992 | N | Austria | 5000001 | [5000005]2 | 2000032 | [2000037]2 | GQ11A-B |
| 1992 | N | European Direct (Belgium, Holland, Italy, Portugal) | 2000032 | [2000105]2 | 2000019 | [2000117]2 | GQ10A-B |
| 1992 | N | France (RC41) | 2000001 | [2000022]2 | 2000001 | [2000020]2 | GQ10A-B |
| 1992 | N | Germany | 2000036 | [2000116]2 | 2000025 | [2000104]2 | GQ10A-B |
| 1992 | N | Japan | |||||
| 1992 | N | Spain | 2000037 | [2000118]2 | 0M000001 | [0M000006]2 | GQ10A-B |
| 1992 | N | Switzerland | 2000039 | [2000108]2 | 2000027 | [2000094]2 | GQ11A-B |
| 1992 | N | U.K. | 2000035 | [2000110]2 | 2000024 | [2000096]2 | GQ10A-B |
Specifications
| Item | Specifications | |
| Dimensions: | Overall length | 2,150mm (84.6 in.) |
| Overall width | 700mm (27.6 in.) | |
| Overall height | 1,090mm (42.9in.) | |
| Wheelbase | 1,435mm (56.5 in.) | |
| Seat height | 785mm (30.9 in.) | |
| Footpeg height | 360mm (14.2 in.) | |
| Ground clearance | 130mm (5.1 in.) | |
| Dry weight | 223.0kg (491.6 lb.) | |
| Curb weight | 244.0kg (537.9 lb.) | |
| Maximum weight capacity | 115.0kg (253.5 lb.) | |
| Frame: | Frame type | Triple-square section twin-tube |
| Front suspension | Telescopic; inverted type | |
| Front wheel travel | 120mm (4.7 in.) | |
| Rear suspension | Vertically-asymmetric Pro-Arm swing arm with Pro-Link | |
| Rear wheel travel | 120mm (4.7 in.) | |
| Rear damper | Nitrogen gas-filled damper with reserve tank | |
| Front wheel | 16x3.5 in. magnesium alloy | |
| Rear wheel size | 17x5.5 in. magnesium alloy | |
| Front tire size | 130/70-ZR16 (Michelin TX11 radial) | |
| Front tire pressure | 270 kPa (2.70 kg/cm²; 39 psi.) | |
| Rear tire size | 180/55-ZR17 (Michelin TX23 radial) | |
| Rear tire pressure | 290 kPa (2.90 kg/cm²; 42 psi.) | |
| Front brakes | Dual disc; 310mm (12.2 in.) with 4-piston caliper and semi-metallic pads | |
| Rear brake | Single ventilated disc; 220mm (8.7 in.) with dual-piston caliper and sintered metal pads | |
| Caster angle | 24-deg 30' | |
| Trail length | 88mm (3.5 in.) | |
| Fuel tank capacity | 17.0 liters (3.74 Imp gal., 4.5 U.S. gal.) | |
| Engine: | Bore (Major x Minor axis) | 101.2 x 50.6mm (3.98 x 1.99 in.) (Equivalent to 75.3mm (2.96 in.) when calculated as a circle) |
| Stroke | 42.0mm (1.65 in.) | |
| Displacement | 747.7 cm³ (45.6 cu in.) | |
| Compression ratio | 11.7 : 1 | |
| Valve train | Cam gear-driven DOHC; 8 valves per cylinder | |
| Intake valve opens (@ 1mm (0.04 in.) lift) | 20-deg. BTDC | |
| Intake valve closes (@ 1mm (0.04 in.) lift) | 50-deg. ABDC | |
| Exhaust valve opens (@ 1mm (0.04 in.) lift) | 46-deg. BBDC | |
| Exhaust valve closes (@ (0.04 in.) 1mm lift) | 16-deg. ATDC | |
| Lubrication system | Forced pressure and wet sump with oil cooler | |
| Oil pump type | Trockoid | |
| Cooling system | Liquid cooled | |
| Air filtration | Oiled paper filter | |
| Crankshaft type | Unit-type; 5 main journals; [360-deg.]2 | |
| Engine weight | 80.5kg (177.5 lb.) | |
| Firing order | #1 @ 270 deg.; #2 @ 90 deg.; #3 @ 270 deg.; #4 | |
| Cylinder arrangement | 90-deg. V4 | |
| Cylinder numbering |  |
|
| Fuel system: | Throttle body | PGM-FI (Programmed Fuel Injection) |
| Throttle bore | 30mm (1.2 in.) x 8 | |
| Drive train: | Clutch system | Multi-plate, wet |
| Clutch operation system | Hydraulic | |
| Transmission | 6 speeds | |
| Primary reduction | 1.937 (62/32) | |
| Final reduction (sprockets) | 2.500 (40/16) | |
| Drive chain slack | 20-30mm (3/4~1-1/8 in.) | |
| Drive chain size/links | 525/108 | |
| Gear ratio, 1st | 2.666 (40/15) | |
| Gear ratio, 2nd | 2.125 (34/16) | |
| Gear ratio, 3rd | 1.777 (32/18) | |
| Gear ratio, 4th | 1.545 (34/22) | |
| Gear ratio, 5th | 1.381 (29/21) | |
| Gear ratio, 6th | 1.240 (31/25) | |
| Gearshift pattern | Left foot operated return system: 1—N—2—3—4—5—6 | |
| Electrical: | Ignition system | Computer-controlled digital transistorized with electronic advance |
| Starting system | Electric starter | |
| Charging system | Triple phase output alternator | |
| Regulator/rectifier type | SCR shorted/triple phase full-wave rectification | |
| Lighting system | Battery (Yuasa YTX12-BS) | |
| Lubrication: | Engine oil capacity at draining | 3.6 liters (3.17 Imp. qt., 3.78 U.S. qt.) |
| Engine oil capacity at disassembly | 4.7 liters (4.14 Imp. qt., 4.94 U.S. qt.) | |
| Engine oil capacity at oil filter change | 3.9 liters (3.44 Imp. qt., 4.10 U.S. qt.) | |
| Recommended engine oil | Use Honda 4-Stroke Oil or equivalent with the Honda UC oil at the prescribed ratio | |
| Recommended engine oil viscosity | SAE 10W-40; API Service Classification: SE, SF or SG | |
| Recommended oil additive | Honda UC Oil | |
| Engine oil/UC oil mixing ratio | 1 liter : 50cc | |
| Oil pressure at oil pressure switch | 600 kPa (6.0 kg/cm², 228 psi) @ 6,000 rpm (80 deg.C, 176 deg.F) | |
| PGM-FI (Programmed Fuel Injection): | Starter valve vacuum difference | 20mmHg [(0.8inHg)]2 |
| Base throttle valve (for synchronization) | No. 3 | |
| Idle speed (except Swiss and Austrian models) | 1,300 +/- 100 rpm | |
| Idle speed (Swiss and Austrian models) | 1,500 +/- 100 rpm | |
| Throttle grip free play | 2-6mm (0.08-0.24 in.) | |
| Ta (air temperature) sensor resistance (@ 20 deg.C/68 deg.F) | 1-4 kOhms | |
| Tw (water temperature) sensor resistance (@ fan motor operating temperature) | 150-400 kOhms | |
| Cam pulse generator resistance (@ 20 deg.C/68 deg.F) | 400-600 kOhms | |
| Fuel injector resistance (@ 20 deg.C/68 deg.F) | 9-14 kOhms | |
| Bypass solenoid valve resistance (@ 20 deg.C/68 deg.F) | 28-32 kOhms | |
| Cam pulse generator peak voltage | 0.7v or more | |
| Crank pulse generator peak voltage | 0.7v or more | |
| Manifold absolute pressure @ idle | 140-180 mmHg | |
| Fuel pressure @ idle | 255 kPa (2.55 kg/cm²; 36 psi) | |
| Fuel pump flow | 150 cm³ (5.26 Imp. oz.; 5.07 U.S. oz.) or more/10 seconds | |
| Secondary air supply system | (Swiss and Austrian models only) | |
| Air suction valve vacuum pressure | 380mmHg | |
| Clutch system: | Clutch lever free play | 10-20mm (0.4-0.8 in.) |
| Recommended clutch fluid | DOT 4 brake fluid | |
| Clutch master cylinder I.D. | 14.000-14.043mm (0.5512-0.5529 in.) (~9/16") | |
| Clutch disc thickness | 3.72-3.88mm (0.147-0.153 in.) | |
| Clutch disc service limit | 3.6mm (0.14 in.) | |
| Clutch plate warpage limit | 0.30mm (0.012 in.) | |
| Cooling system: | Coolant capacity (radiator & engine) | 2.9 liters (2.55 Imp. qt., 3.05 U.S. qt.) |
| Coolant capacity (reserve tank) | 0.34 liter (0.30 Imp. qt., 0.36 U.S. qt.) | |
| Radiator cap relief pressure | 110-140 kPa (1.10-1.40 kg/cm², 16-20 psi) | |
| Thermostat begins to open | 80-84 deg.C (176-183 deg.F) | |
| Thermostat fully opens | 95 deg.C (203 deg.F) | |
| Thermostat valve lift | 8.0mm (0.23 in.) min. | |
| Front suspension: | Fork spring free length | 251.7mm (9.91 in.) |
| Fork spring direction | Taper-wound coil facing up | |
| Recommended fork oil | Fork fluid [(5wt)]2 | |
| Fork oil level | 56mm (2.2 in.) | |
| Fork oil capacity | 580 cm³ (20.36 Imp. oz; 19.62 U.S. oz) | |
| Steering bearing pre-load | 9-14 Nm (0.9-1.4kg; 2.0-3.1 lb.) | |
| Rear suspension: | Shock spring free length | 160.0mm (6.30 in.) |
| Shock spring installed length | 147.6mm (5.81 in.) | |
| Nitrogen gas pressure | 980 kPa (10.0 kg/cm²; 142 psi) | |
| Brakes: | Brake fluid type | DOT 4 |
| Front brake disc thickness | 5.0mm (0.20 in.) | |
| Front brake master cylinder I.D. | 14.000-14.043mm (0.5512-0.5529 in.) (~9/16") | |
| Front brake caliper cylinder I.D. (upper) | 27.000-27.050mm (1.0630-1.0650 in.) | |
| Front brake caliper cylinder I.D. (lower) | 30.230-30.280mm (1.1902-1.1921 in.) | |
| Rear brake disc thickness | 9.0mm (0.35 in.) | |
| Rear brake master cylinder I.D. | 12.700-12.743mm (0.5000-0.5017 in.) (~1/2") | |
| Rear brake caliper cylinder I.D. | 25.400-25.450mm (1.0000-1.0020 in.) | |
| Battery/Charging system: | Reg/rec regulated voltage | 12.6-15.0v @ 3,000rpm |
| Battery capacity | 12v-10Ah | |
| Battery charging rate (normal) | 1.2A/5-15 hr. | |
| Battery charging rate (quick) | 5.0A/1 hr. | |
| Battery voltage | 13.1v | |
| Front brake master cylinder I.D. | 14.000mm (0.5512 in.) (9/16") | |
| Front brake caliper cylinder I.D. (upper) | 32.030mm (1.2610 in.) | |
| Current leakage | 1.5mA maximum | |
| Alternator/charging coil resistance (@ 20 deg.C/68 deg.F) | 0.1-0.5 Ohms | |
| Ignition system: | Spark plug (standard) | NGK ER9EH or ND Y27FER-C |
| Spark plug (extended high-speed riding) | NGK ER10EH or ND Y31FER-C | |
| Spark plug (cold climate/below 5 deg.C/41 deg.F) | NGK ER8EH or ND Y24FER-C | |
| Spark plug gap | 0.6-0.7mm (0.024-0.028 in.) | |
| Ignition timing "F" mark (except Swiss and Austrian models) | 15-deg. BTDC @ 1,300rpm | |
| Ignition timing "F" mark (Swiss and Austrian models) | 10-deg. BTDC @ 1,500rpm | |
| Advance starts | 2,000rpm | |
| Advance stops | 5,000rpm | |
| Lights/Meters/Switches: | Main fuse A | 30A |
| Main fuse B | 55A | |
| Fuse | 30A x 1; 10A x 6 | |
| Headlight (high beam) | 12v 60/55w (H4; low beam portion not used) | |
| Projector headlight (low beam) | 12v 55w (H3) | |
| Position light | 12v 5w | |
| Turn signal lights | 12v 21w | |
| Tail/brake light | 12v 5/21w x 2 | |
| License light | 12v 5w | |
| Turn signal indicator | 12v 3w x 2 | |
| High beam indicator | 12v 1.7w | |
| Neutral indicator | 12v 1.7w | |
| Side stand indicator | 12v 3w | |
| Oil pressure warning indicator | 12v 3w | |
| Fuel reserve warning indicator | 12v 3w | |
| PGM-FI warning indicator | 12v 1.7w | |
| Instrument light | 12v 1.7w x 5 | |
| LCD light | 12v 8w | |
| Starting system: | Starter motor brush length | 12.0-13.0mm (0.47-0.51 in.) |
Notes:
This text appears (verbatim) at the front of the Workshop Manual
Unconfirmed
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Copyright © VSource.org 1999-2011 [Sources: Honda NR750N Workshop Manual (pn. 67MT700), Parts Catalog (pn. 13MT7N92) and Owners Manual (pn. 32MT7600C)] |