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DME Circulars

Back to change notice

During 1940 a system was introduced to control/request/demand modifications to existing equipment in use (not limited to motorcycles).
Some of these modifications were lateron standardised by the motorcycle manufacturers.
The instructions were devised by "The Directorate of Mechanical Engineering" and changes/guidelines were published in so called D.M.E. (modification) circulars.
The existence of those circulars is known for quite a number of years (2008) based on a listing found in "Questionaire on the Norton, B.S.A. Matchless Ariel and Royal Enfield motorcycles" prepared by the Royal Artillery Mechanical Traction School (R.A.M.T.S.  14/4 October 1943) showing the titles of circulars pertaining to motorcycles.

Unfortunately only very few of the individual circulars have surfaced over the past decade. Story goes that they were destroyed after a certain time to prevent the accumulation of too much paperwork.

Some of the descriptions are fairly cryptic giving hardly enough information to understand what is meant to be done.
Some others lift the vail on when certain changes came into being, e.g. the provision for immobilizing or the introduction of pannier equipment.

Anyone with access to DME circulars is requested to come forward for the greater understanding.
 


Below is a survey of the original  D.M.E. cirulars (transcripted for clarity) valid for Nortons.
 

Particulars of D.M.E., Circulars

affecting Norton, B.S.A. Matchless, Ariel and Royal Enfield Motor-

cycles, available up to October, 1943.

 Circular No.

Date

Purport  

Motorcycle

 

IMMEDIATE ACTION

 B.40

28-10-1940

Fitting of Security Bolts to prevent damage to valves

Norton

 B.141

12-5-1941

Fitting of new headlamp mask and removal of dipper switch.

All M/Cís

 B.125

21-7-1941

Provision for immobilizing.

All M/Cís

 B.155 

6-3-1942

Fitting pannier bags and pillion seat conversion sets.

Norton

 B.173

8-4-1942

Carburetter Ė adjustment for petrol economy.

B.S.A. Norton

 B.301

21-5-1942

Spanner for dynamo securing strap nut.

All M/Cís

 B.417

31-3-1943

Dynamo bracket screw at driving pinion end of Lucas Magdyno.

Norton, B.S.A.,   Ariel, R.Enfield

 

 

 

 

WHEN NECESSARY

 B.19

1-10-1940

Petrol tank lugs. (Fracturing).

Norton

 B.46

19-11-1940

Rear stand and mudguard.

Norton

 B.41

24-2-1941

Fitting flexible petrol and oil pipes.

Norton

 B.212

16-11-1941

Modification to horn bracket.

Norton

 B.173

8-4-1942

Carburetter Ė adjustment for petrol economy.

B.S.A. Norton

 B.257

12-5-1942

Fitting panel air cleaner in Mid. East. 

Norton

 B.210

15-5-1942

Rear stand method of repair.

Norton

 B.212/1

16--7-42

Amendment No.1. Cancels B.212

Norton

 B.323

31-7-1942

Dynamo and regulator wiring.

All M/Cís

 B.304

7-9-1942

Change speed mechanism - Bushes fitted to cam plate and spring cover plate.

Norton

 B.413

17-2-1943

Petrol pipes.

Norton

 

 

 

 

Circular No.

Date

Purport  

Motorcycle

 

GENERAL INSTRUCTIONS

 B.106

26-4-1941

Dublchek Schrader valve caps.

All M/Cís

 B.174

8-8-1941

Ignition timing.

All M/Cís

 B.211

14-10-1941

Procedure for reporting faults on A.F.G.889.

All M/Cís

 B.217

31-10-1941

Maintenance of Spark Plugs

All M/Cís

 B.260

31-10-1941

Kickstarter ratchet gears.

All M/Cís

 B.407

4-2-1942

ďTargetĒ fuel consumption figures, (M.P.G.)

All M/Cís

 B.200

20-3-1942

Tyre Pressure.

All M/Cís

 B.127

16-5-1942

Method of fitting chevron tyres.

All M/Cís

 B.268

12-6-1942

Replacement of Tecalemit grease nipples.

All M/Cís

 B.313

8-7-1942

Initial Inspection.

All M/Cís

 B.325

8-8-1942

Limit of wear outer covers.

All M/Cís

 B.402

21-11-1942

Handlebar grips Ė rubber substitute, method of fixing to handlebars, and twist grip rotors.

All M/Cís

 B.400

21-1-1943

List of tyre pressures. (Cancels B.200).

All M/Cís

 B.456

25-2-1943

New range of lubricants W.D. ďBĒ Vehicles.

All M/Cís

 B.345

11-5-1943

Security bolt (front wheel).

All M/Cís

 B.400/1

12-5-1943

Amendment to B.400.

All M/Cís

 B.517

16-7-1943

Defects, rendition of A.F.G.889 in accordance with A.C.I.2240 of 1942 (Cancels B.211) .

All M/Cís

 

 

 

 

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