Norton Commando Technical Information
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Engine Specs
| 750 | 850 | |
|
Capacity
|
745cc (45 cu. in.) | 828cc (50.5 cu. in.) |
|
Bore
|
2.875 in. (73mm) | 3.030 in. (77mm) |
|
Stroke
|
3.503 in. (89mm) | 3.503 in. (89mm) |
|
Max. Torque(5000 rpm)
|
48 lb./ft. (Combat 49lb) | 56 lb./ft. |
|
Compression Ratio
|
9:1 (Combat 10:1) | 8.5:1 |
|
Maximum Speed
|
112 MPH (Standard) | 122 MPH |
|
Spark Plug
|
Champion N7Y or Equivalent. | |
|
Spark Plug Gap
|
.023 – .028 in. | |
|
Contact Breaker Gap
|
.014 – .016 in. | |
|
Ignition Timing
|
28 degrees BTDC (Fully Advanced) | |
|
Valve Clearances (Cold)
|
750 | 850 |
|
Inlet
|
.006 in. (Combat .008) | .006 in. |
| .008 in. (Combat .010) | .008 in. | |
|
Camshaft Chain Adj.
|
3/16 in. (4.8mm) play at top of chain. | |
|
Valve Seat Angles
|
45 degrees inlet and exhaust | |
Primary, Transmission & Rear Chain
|
Engine Sprocket
|
26 Teeth |
|
Clutch Housing
|
57 Teeth |
|
Primary Chain
|
Triple Row, 92 Pitches, .375in. x .250in. |
|
Rear Chain
|
99 Pitches, .400in. x .380 in. |
|
Clutch Pushrod Length
|
9.813/ 9.803 in. (244.250/ 243.996 mm) |
|
Clutch Pushrod Diameter
|
.237/ .232 in. (6.019/ 5.892 mm) |
|
Clutch Ball Bearing
|
1/2 in. (12.70) Diameter |
| 4 fiber clutch, 5 metal clutch (Sintered Bronze) | |
|
Clutch Adjuster
|
1/2 in. x 20 UNF 2A |
|
Clutch Adjuster Length
|
.904 in. x .894 in ( 22.962/ 22.708 mm) |
Gearbox
|
Estimated Speeds Using 19-23 Tooth Gearbox Sprockets |
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| Sprocket Size | Overall Gear Ratio | 6000 rpm | 6500 rpm | 7000 rpm |
| 19 | 4.84 | 92 mph | 99 mph | 107 mph |
| 20 | 4.60 | 97 mph | 105 mph | 113 mph |
| 21 | 4.38 | 102 mph | 110 mph | 119 mph |
| 22 | 4.18 | 106 mph | 115 mph | 121 mph |
| 23 | 3.99 | 112 mph | 121 mph | 130 mph |
|
( I recommend using a 20 or 21 tooth sprocket depending on where you live) |
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|
Number Of Teeth On Pinions |
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|
First Layshaft 28 teeth
|
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|
Second Layshaft 24 teeth
|
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|
Third Layshaft 20 teeth
|
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|
Fourth Layshaft 14 teeth
|
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|
First Mainshaft 14 teeth
|
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|
Second Mainshaft 18 teeth
|
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|
Third Mainshaft 21 teeth
|
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|
Fourth Mainshaft 23 teeth
|
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|
Ball Journal Bearings |
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|
Mainshaft (Kickstarter) 5/8 x9/16 x 7/16 in.
|
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|
Layshaft (Clutch) 17mm x 40mm x 12mm
|
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Carburetor & Air Filter
Frame & Isolastics
|
Front Isolastic |
|
|
Shim Thickness Available
|
.005, .010, .020, .030, in. |
|
Free Play
|
.010 in. |
|
Bolt
|
7.13 in., 1/2 in. x 20 UNF. |
|
Buffer Quantity
|
2 |
|
Buffer Diameter
|
1 11/16 in. |
|
Buffer Thickness
|
1/2 in. |
|
Bush Quantity
|
2 |
|
Bush Thickness
|
5/8 in. tapered to .510 in. |
|
Spacer
|
2.573/ 2.553 |
|
Rear Isolastic |
|
|
Bolt Torque Setting
|
300 in./ lb. |
|
Shim Thickness Available
|
.005, .010, .020, .030, in. |
|
Free Play
|
.010 in. |
|
Stud
|
13 in. |
|
Stud Thread Size
|
1/2 in. x 20 UNF 2A |
|
Buffer Quantity
|
2 |
|
Buffer Diameter
|
1 5/16 in. |
|
Buffer Thickness
|
1/2 in. |
|
Bush Quantity
|
3 |
|
Bush Thickness
|
1/2 in. tapered to .410 in. |
|
Spacer
|
1.560 in./ 1.550 in. |
|
Dimensions |
|
|
Height
|
40.75 in. |
|
Length
|
87.5 in. |
|
Wheelbase
|
56.75 in. |
|
Weight (Roadster)
|
420 lb |
|
Weight (Interstate)
|
435 lb. |
|
Width
|
26 in. |
| 17ft.10 in. | |
|
Center of Gravity
|
19 3/4 in. |
|
Seat Height
|
33 1/2 in. |
Forks & Shocks
|
Forks ( Telescopic with internal Springs Hydraulically damped) |
|
|
Total Fork Travel
|
6 in. |
|
Fork Leg Oil Capacity
|
150 cc in each leg |
|
Springs
|
75 1/2 Coils |
| 18.687 in. free length | |
| 36.5 lb./ in | |
|
Shocks (Girling Oil filled with External Springs) |
|
|
Spring Free Length
|
8.75 in. |
| 126 lb. per in. (depends on adjustment) | |
|
Fitted Length
|
8.4 in. |
|
Total Length
|
13 in. |
Brakes, Wheels & Tires
|
Front Wheel |
|
|
Rim Size
|
WM2 – 19 in. |
|
L.H. Wheel Bearing
|
17x40x12 mm. |
|
R.H. Wheel Bearing
|
NM 17721 |
|
Spindle
|
.66671/ 6670 in. |
|
Tire Size
|
4.10 x 19 in. |
|
Tire Pressure
|
26 PSI |
|
Tire Diameter
|
26.46 in. (Dunlop) |
|
Tire Width
|
4 in. |
|
Front Brake (Disc) |
|
|
Pad friction area
|
1.65 in. |
|
Pad Thickness (New with Backing)
|
.38/ .37 in. |
|
Pad Minimum Thickness
|
.0625 in. |
|
Disc Diameter
|
10.70 in. |
|
Disc Width
|
.260/ .250 in. |
|
Brake Fluid
|
Lockheed 329 Quality |
|
Front Brake (Drum) |
|
|
Type
|
Twin Leading Shoe |
|
Drum Diameter
|
8 in. |
|
Brake lining area Total
|
18.69 Sq. in. |
|
Rear Wheel |
|
|
Rim Size
|
WM2 – 19in. |
|
Wheel Bearings
|
17x40x12 mm |
|
Sprocket Bearing
|
NM 177721 |
|
Tire Size
|
4.10x19in. |
|
Tire Pressure
|
26 lbs./PSI |
|
Tire Diameter
|
26.46 in. |
|
Tire Width
|
4 in. |
|
Drum Internal Diameter (New)
|
7.007/ 6.997 in. |
|
Brake lining area Total
|
13.6 Sq.in. |
Electircal
|
General |
|
|
Voltage
|
12 V Positive earth/ ground |
|
Alternator
|
RM 21 |
|
Rectifier
|
2 DS 506 |
|
Zener Diode
|
Z D 715 |
|
Battery Rating
|
10 Amp Hour at !0 hour rate |
|
Coil
|
17 M6 |
|
Ballast Resistor
|
3 BR |
|
Contact Breaker
|
6 CA or 10CA |
|
Warning Light Assimilator
|
3 AW |
|
Fuse
|
35 Amp. |
|
Flasher Unit
|
8FL |
|
Bulbs |
|
|
Headlight
|
12 V 45/40 Watt |
|
Tail/ Stop light
|
12V 21/ 6 Watt Offset |
| 12V 6 Watt Bayonet | |
|
Direction Indicators
|
12V 21 Watt |
|
Warning Lights
|
12V 2 Watt |
Torque Settings
|
3/8 in. Cylinder head nuts & bolts
|
30 ft./lb. |
|
5/16 in. Cylinder head bolts
|
20 ft./lb. |
|
3/8 in. Cylinder base nuts
|
25 ft./lb. |
|
5/16 in. Cylinder base nuts
|
20 ft. /lb. |
|
Cylinder through bolt (850cc)
|
30 ft./lb. |
|
Con rod nuts
|
25 ft./lb. |
|
Rocker cover plate bolt
|
8 ft./lb. |
|
Crankshaft nuts
|
25 ft./lb. |
|
Cam Chain tensioner nuts
|
15 ft./lb. |
|
Oil Pump stud nuts
|
15 ft./lb. |
|
Rocker feed banjo bolts
|
15 ft./lb. |
|
Engine mount bolts
|
25 ft./lb. |
|
Rotor nut
|
80 ft./lb. |
|
Alternator stud nuts
|
15 ft./lb. |
|
Clutch to Mainshaft nut
|
70 ft./lb. |
|
Mainshaft nut
|
40/50 ft./lb. |
|
Counter shaft sprocket nut
|
80 ft./lb. |
|
Gearbox inner cover nuts
|
12 ft./lb. |
|
Top gearbox fixing bolts
|
55 ft./lb. |
|
Rear shock nuts
|
30 ft./lb. |
|
Isolastic bolts
|
25 ft./lb. |
|
Fork Top nuts
|
30 ft./lb. |
|
Fork Yoke Pinch bolts
|
30 ft. /lb. |
|
Steering head main nut
|
30 ft./lb. |
|
Disk Caliper mounting bolts
|
30 ft./lb. |
|
Disk Caliper end plug
|
26 ft./lb. |
|
Disc Mounting nuts
|
20 ft./lb. |
|
Drum brake cam nuts
|
30 ft./lb. |
|
Sidestand nut
|
50 ft./lb. |
|
Zenor Diode nut
|
2 ft./lb. |
| 1 ft./lb. | |
|
Oil pressure release valve
|
25 ft./lb. |
Capacities
|
Engine oil tank
|
5 imp./ 6 US. Pints |
|
Primary Chaincase
|
200 cc, 7 fl.oz. |
|
Gearbox
|
.75 imp./ .9 US. Pints |
|
Front Forks
|
150 cc, 5 fl.oz. |
|
Interpol fuel tank
|
4 imp. gallons |
|
Interpol fuel tank (radio)
|
3 1/2 imp.gallons |
|
Interstate fuel tank
|
5 1/2 or 5 1/4 gallons |
|
Hi Rider fuel tank
|
2 imp. gallons |
|
Roadster fuel tank
|
2 1/4 or 2 1/2 gallons |
|
Fastback fuel tank
|
3 1/4 or 4 gallons |