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Norton Commando

Updated 12/02/23

Norton Commando

Updated 06/26/22

Norton Commando

Updated 11/26/23

Norton Commando
Head Stud Study

Updated 11/25/23

Norton Commando
Service Releases

Updated 06/13/22

Norton Commando

Updated 09/17/23

Special Parts
Updated 06/18/23

Used Parts For Sale
Updated 09/13/20

High Mileage 850
Updated 10/14/23

Customer Combat
Build Oct 23

Updated 12/03/23

Norton Rear
Wheel Lacing

Updated 05/06/22

Norton Front
Wheel Lacing

Updated 10/22/21

Norton Front
Forks Helper

Updated 01/08/23

Norton Wiring
Updated 09/02/23

Norton Wiring Diagrams
Updated 02/28/21

Combat 5
Updated 11/07/23

Roadster 850
Updated 08/07/23

1973 Customer
BasketCase Build

Delivered 07/15/22

1974 Norton 850
Commando Rebuild

Sold 01/12/21
Updated 06/10/21

1974 Norton Wiring
Updated 11/21/21

1972 Norton 750
Commando Rebuild

Completed 05/15/19
First Place Norton 5/16/19
Sold 01/01/20

1972 Norton Wiring
Updated 09/06/20

Customer Combat
and 69S Builds

Closed 10/18/23
Welcome to the Norton Commando Service Release Database
We're providing this system as a service to the Vintage British Motorcycle community. You can search by all or part of any field. Click the link in the left-hand column to see the service release formatted more-or-less how it was originally published. Use the Show all link to clear any search parameters and/or to refresh. You can sort by clicking the header of the column to sort. Put a check in Long Pages to list more items at a time.

Note: This is a work in progress. All available services releases are here, but some have missing drawings and some may have typoes (more than those made by Norton).

Norton used a naming convenion for the later Service Releases. For more info see N3_4
  • Nx = Prior to May 1972 (e.g., N1, N6 , N48, etc.)
  • N1_x = Distributors (e.g., N1_01, N1_03, etc.)
  • N2_x = Angents and Distributors (e.g., N2_2, N2_6, etc.)
  • N3_x = General Distribution (e.g., N3_45, N1_81, etc.)
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Page   of  7   ( 140 Items )

Number Nature Explanation Action
N1/01 Kickstart foul on right exhaust pipe. An alteration has been introduced onto the muffler bracket to provide adequate kickstart pedal operating clearance.

The new bracket, which should only be fitted to the right hand side pipe is supplied under part number 063579.

Alternatively the existing right hand bracket may be re-formed as indicated below.

N1/02 Alternative hydraulic hose lengths (disc brake) It has been decided to make available alternative lengths of brake hose which can be ordered by distributors and made available at their discretion. Below are listed all the available hydraulic brake hoses with part numbers and lengths:

Standard hose 062707 Length 25in.


063508 23in.

063507 28in.

063541 31in.

063540 34in.
Where disc braked Commando models are equipped with alternative heights of handlebar, select the most suitable hose length from the list above.
N1/03 Availability of quartz halogen light units. Quartz halogen light units are now available as a kit through the Spares Department to convert existing headlamp units. The conversion is available only for 7in. diameter headlamps and thus cannot be incorporated on Hi-Rider and SS models. The conversion kits available are:

Left hand dip set comprising:

54526114 Light unit

463 Bulb

553738 Bulb holder adaptor

Right hand dip set comprising:

54526323 Light unit

472 Bulb

553738 Bulb holder adaptor
Where quartz halogen light units are legally acceptable for your market, order the requisite number of conversion kits as normal spares requirements.
N1/04 Reproduction To avoid production delays a Factory policy decision has been taken that in future main Distributors will be responsible for the reproduction and distribution of Service Releases. This will be done from text and, where necessary, artwork supplied from the Factory. The Factory will furnish main distributors with bulk supplies of headed paper to aid reproduction locally.

The reproduction method adopted is left to the distributor's discretion, dependent upon the length of his mailing list. It is most important to retain the Factory number sequence.
Advise Technical Department Wolverhampton, England, of the quantity of Service Release headings required and periodically call up further quantities as necessary.
N2/01 Modification to exhaust valve guides. The design of exhaust valve guide NMT2011 has been revised to prevent excessive oil passage between the valves and guides. The upper end of the guide has been shortened so that the taper on the valve stem cannot enter the neck of the guide which would cause a pumping action. To avoid reducing the supporting length of the guide, the lower end of the guide has been lengthened by a similar amount. The modified valve guide is being supplied against part number 063527, and as stocks are exhausted, the later guide will supersede the earlier type directly Until dealer stocks of the taller guide are exhausted, ensure where possible that exhaust valve guides are used in pairs.
N2/02 Clutch plate oil disposal grooves. The clutch friction plate 061339 now incorporates scrolled oil dispersal grooves on both sides. The friction plates shown in the Parts List incorporate such grooves but this modification was not in fact effective during the1971season. The purpose of the grooves is to disperse oil which can otherwise cause clutch slip. Factory stocks of friction plate 061339 have had the oil dispersal groove added so that future supplies will be to the latest design. It is not necessary to return dealer stocks to the factory but in cases where clutch slip can be attributed to oil on the plates, the modification detailed in Service Release N5 should be carried out.
N2/03 Combat valve springs. On certain Combat engines from the initial production batch, we have become aware of a condition which prevents the valves opening sufficiently At the first service or first convenient opportunity, check that the valve springs are not preventing the valves opening fully. With the fuel tank and rocker covers removed, turn the engine until any valve is opened fully, i. e. is depressed into the cylinder as far as permitted by the valve operating gear. At this stage push down the rocker adjuster against the valve stem, such as with an aluminium or wooden shaft, and ensure that the valve can move perceptibly as the spring is depressed further. Repeat this check on all valves in turn. Perceptible movement indicates that all is well but a lack of movement will necessitate the use of a new thinner bottom valve spring cup part number 063996 The thinner bottom cup is identified by the marking "IN" on the inner facing. As an alternative to using new cups, the NMT2073 may be reduced in thickness to 0.065in . (1.65mm).

The above check applies only to engine number series 200004 to 202340.Thin bottom valve spring cup washers 063396 were fitted from 2023 >>>
N2/04 Combat and standard Commando In order to meet early 1972 production requirements, an interim piston has been produced to accommodate the additional valve lift of the Combat engine, As the new interim Combat pistons differ only from the previous Commando type in the depth of the valve cutaways, the new pistons are therefore currently specified for both standard Commando and Combat versions and supersede the previous pistons 062459(L.H.) and 062462(R.H.). When the final Combat pistons become available, they will be of the solid skirt variety and completely interchangeable with the interim Combat pistons (though, ideally, in pairs). The part numbers of the various pistons are detailed below:

Incoming orders for solid skirt pistons will be fulfilled from interim version stocks until the changeover is completed. Note that on a production basis interim pistons were introduced from engine number 200976 and final Combat pistons from engine number 204166.
N2/05 Introduction of disc-brake conversison kit. We have received a considerable number of enquiries for the parts necessary to incorporate the new Norton-Lockheed hydraulically operated disc brake on a Commando previously equipped with the cable operated drum brake. In view of this interest, we have introduced a disc brake conversion kit under part number 063412 which incorporates all the parts needed for this conversion. The kit is offered at a very attractive price and the following list shows the parts incorporated in the kit which is in the form of a cartoned semi-display pack:

N2/06 Crankshaft Main Bearings. Field experience with 1972 models (incorporating two single lipped roller main bearings) indicates a small, but significant premature roller main bearing failure rate.

Reported failures have been confined solely to one type of bearing.
When replacing defective roller main bearings, ensure the replacement is a Skefco double lipped outer, single lipped inner spool type NJ306, with a specified nominal internal diametral clearance of 0.0008/0.0012ins. (0.02/0.03mm) Prior to fitting (180 Normal).

Ensure the crankshaft journals are carefully cleaned up, removing all signs of butts or scoring before fitting the inner spool. Models subsequent to Engine Number 207197 incorporate a nominal increase in bearing housing diameter to overcome any significant tendency to excessive closure of the single lipped outer series of roller bearings.
N2/07 Removal of inhibitor coating from new motorcycles. All new motorcycles are sprayed with a protective coating after road test and prior to despatch from the factory. The protective coating should be removed before the motorcycle is offered for sale but the choice of solvent must avoid those likely to cause deterioration of any parts, though none of the suitable solvents should be allowed to remain on the tyres. Remove the protective coating by brushing with any hydrocarbon solvent. The following are recommended:

Petrol (Gasoline) preferred

Carbon Tetrachloride


Paraffin (Kerosene)
N2/08 Hydraulic Steering Damper Kit, Part Number 064247 Resulting directly from racing expcrience, and in acknowledgement of popular demand, an adjustable hydraulic steering damper kit complete with all attachment brackets, is now available through Norton Villiers spares channels.

The kit comprises a fully adjustable hydraulic steering damper, part number 064230 and mounting attachments as listed below, and can be fitted to all Commando models.

A fully illustrated fitting leaflet, part number 064629, is supplied with each kit, extra copies of which may be obtained for display purposes.

Note : The steering damper kit will be found particularly useful in restricting handling problems occasioned by crosswinds, rutted road surfaces, Grooved freeway surfaces, heavy touring luggage etc. It is not intended to rectify maladies in handling occasioned by incorrect maintenance, though an improvement even in these undesirable conditions may well be noted.
N2/09 Crankshaft main (roller) bearings In order to extend main bearing life, a change of roller main bearing specification has now been authorized, and fitted on production engines from engine number 211891.

The new roller bearing is designated "Superblend" with an increased load carrying capacity and are supplied under part number 063906 (manufacturers part number R & M 6/MRJA30.
Where engine units are stripped for examination, or the need for main bearing replacement, fit only roller main bearings part number 063906 in place of the previously specified 063114.

The new bearings are fully interchangeable, and should be fitted in pairs for maximum reliability.

Note: The new bearings may also be fitted to advantage to 1971 and earlier Commando machines, provided care is taken fitting the inner spool to the right side crankshaft journal (was 1.1807in. 1.1812in.) diameter, now 1.1812in. 1.1815in. diameter. Also crankshaft fitted end float should be checked, and shimmed where necessary to provide 0.010in. min. 0.020in. max. end float using shim part number NMT2196A as necessary.
N2/10 Extra high capacity main bearings A new main bearing capable of carrying a much higher load than any offered before, has been introduced.

The new bearing, part number 064118 , supersedes the old type 063906 and will be supplied in lieu by our Parts Division. The new bearing should be fitted in pairs.

This bearing may also be fitted to advantage to engines of 1971 and earlier models (originally fitted with a ball bearing as a timing side main bearing).

Ensure that the inner races are firmly seated against the crankcheeks to give a crankshaft end float between 0.010 and 0.024. Any excessive end float can be eliminated by fitting main bearing shims NMT2196A between the outer race and the crankcase.
N2/11 Achieving legal noise levels All 1973 750 models excepting Hi-Rider have the muffler tail cone mutes supplied separately in the crate in the plastic bag containing the front fender hardware. To meet legal noise requirements for noise limitations in some States it is most essential for the mutes to be fitted before the motorcycle is offered for sale, for otherwise both the selling dealer and new owner may be in violation. The fitting of the mutes necessitates changes to carburetor settings including the fitting of the main jets supplied. Insert the mutes in the muffler tail cones, lipped end rearwards, align the holes in the mutes and mufflers and fit the self-tapping securing screws securely.

Fit the new main jets by turning off the fuel, removing the carburetor float bowls and holding the main jet holders to prevent turning as the original main jet is removed from the carburetor. Fit the size 220 main jets supplied and refit the float bowls. Remove the carburetor tops, lift out. the throttle slides attached to the cables and re-locate the needle clips in the top groove of each needle. Refit the slides and tops.
N3 Carburetter Specification Change To meet recent U.S.A. legislation it has been necessary to introduce megaphone silencers modified to provide a lower noise level than the original megaphone type. The later type are modified by the fitting of a perforated tube in the end cone and their use necessitates the fitting of smaller main jets. The two types of silencer end cone are shown below:

Examine the megaphone silencer end cone. If this is hollow as the early type above, the jet size should be 220. If the end cones have a perforated tube as in the late type above, the main jet size should be 180.
N3/01 Tyre pressure recommendation Tyres produced by two different manufacturers are used, in pairs, on Commando models. Due to the different characteristics of the tyre walls, although varying tyre pressures are advantageous under certain circumstances, the front and rear tyre pressures must remain equal for Avon tyres but not for Dunlop. We therefore recommend a minimum tyre pressure of 26 p.s.i. for Avon tyres front and rear. In the case of Dunlop tyres the following pressures are approved:

N3/02 Fuel requirements. The Norton Commando is designed to operate on the following fuels: The following alterations will be required to operate on lower grade fuels:

Do not use fuels lower than the alternative ratings and setting given above. A small power loss is to be expected utilising the changes recommended.
N3/03 Reversal of handlebar switch clusters. As a direct result of user requests for right hand operation of the direction indicators, the decision has been taken to interchange the left and right and switch clusters. To save changing wiring colour identification at 6 connectors, the functions of kill button and headlamp flasher and spare button and horn shown in Illustration 2 of the Riders Manual are also reversed. New prints of the handbook will include this modified layout but where motorcycles have been despatched which are at variance to the handbook, the supplying dealer is requested to acquaint the new owner with the revised layout. From the time of the changeover, the revised control positions will be: Ensure that all new owners of modified models are suitably briefed.
N3/04 Method of issuing Service Releases To improve continuity in the issue of Service Releases, we shall from now on issue releases in the 4 separate sequences dependent upon destination. The sequences are:

The Service Releases will then bear the number, e.g. 'N' (indicating Norton) 2 (Agents/distributors) followed by the sequential number.

viz No, N2/49

The change in method of issue means that each source will from now on be able to maintain a complete file in ascending number order without missing numbers as previously has been the case.

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