Technical Notes

It is a number of years since the club published  "Notes on the Maintenance and Overhaul of the Velocette L.E. Model" . These notes were presented in a  ring binder and compiled by Dave Rix, our past Technical Secretary, and when  used with the workshop manuals, proved to be invaluable for restoration and servicing work on all L.E. models.

The committee decided to release a limited number of photocopies of these notes (less binder) which can be purchased from Dennis Frost the Club Historian. Details can be obtain from his "Historians Notes" in number 429 of the O.T.L. magazine.

However "Notes on the Maintenance and Overhaul of the Velocette L.E. Model" have now been successfully digitized and are available to all members for perusal and use free of charge through this web site.

The Notes are split into sections as follows:-

1)    History

2)    Engine

3)    Reduction Gear Starter and Clutch

4)    Gearbox Rear Fork and Final Drive

5)    Fuel System

6)    Frame Radiator and Exhaust

7)    Suspension Wheels and Brakes

8)    Electrical

9)    Miscellaneous

The notes are digitized in PDF format for which an Adobe Acrobat reader will be required. This is available free and can be downloaded from a lot of web sites or from below.

Download Adobe Acrobat Reader from here


These files are large in size and will take some considerable time to download - especially with a slow modem - and it is advisable to download the zipped file for the complete manual onto your hard disk. This zipped file can be found when you enter the secure site, or each file can be downloaded individually to your hard disk by highlighting the individual file then clicking the right button on the mouse.

To gain access click on the following link, this will shell out to a further page where two security questions will be asked, both are the same answer. This security word can be obtained from the Webmaster please state your name and address, this will ensure that only registered club members can gain access.

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The Velocette Service Bulletins from 1950 - 1960

These service bulletins were issued by the factory to the dealership giving advice and amendments and clarification for all the manufactured models at the time of issue. They were laboriously typed out and issued as copies.

Below are extracts from the above bulletins that relate to the L.E.s. Only parts of the notes are reproduced, these parts are selected - by myself -  as being the most informative and useful information and sometimes amusing  for today's LE owners.

 APRIL 1952


1)    Despite the illustration in the Owners Instruction Book and what we thought to be clear instructions on the subject, two cases have come to light recently of the domed sump cap being refitted upside down after an oil change and cleaning of the strainer.

In both cases the cover - incorrectly fitted convex side up - had covered the opening in the oil pump suction bolt LE161 cutting off the oil supply entirely. Please warn any customer who might remove the dome cover that it must fit with the dome (convex) side downwards to allow a clear space between the head of the hollow bolt and the cover.


2)    The short 3/16" dia. thrust pin now fitted at the front end of the primary gear shaft - see new service manual page 14 Fig.9. - is to be produced with one end tapered off to enable the pin to be pushed back into the bush in the shaft should it be drawn out of the bush to the rear when pulling out the two thrust rods. When replacing the thrust pin make sure that the tapered end is facing forward - contacting the thrust button in the pressure plate assembly.

JULY 1952


1)    It is necessary occasionally to clean the accumulated deposit of carbon from the tail pipe. This can be done conveniently when decarbonising the engine. The pipes of any machine taken in for attention should be inspected, and if partially choked should be scraped clear. A note on this subject is included in the recently reprinted LE Owner's Handbook (F.437/2R) page 46.



1)    Beginning at engine number 200/17801 an Aluminium Alloy clutch bell is fitted and this has necessitated modification of the clutch lining.

The new parts are:-

LAS.29/2 Clutch Bell Assembly    1 off

LE. 93/2 Clutch Lining                    2 off

When supplies of LAS.29 clutch bell assemblies are exhausted it will be necessary to use the new assembly LAS.29/2 and two LE.93/2 linings. The assembly LAS.29/2 will not take the old linings LE.93 and the new linings LE.93/2 are unsuitable for use with the old bell assembly LAS.29.


2)    The present is a suitable time to remind LE owners that precautions must be taken against damage by frost.  The water should be drained from any machines laid up for the winter. Those machines which are to be kept in use should have an anti-freeze solution put into the cooling system. Half a pint of 'Bluecol' or similar compound is sufficient to treat one machine. Full details are given in the Owners Handbook F.437/2R page 21. In addition to the use of anti-freeze solution we recommend Agents to advise owners to blank off a portion of the radiating surface of the radiator. Two 1 and 1/2" wide sections, one on each side from top to bottom should be covered. Ordinary cardboard may be waterproofed by enamelling and will be quite suitable. The blanking will cause the engine to reach and efficient working temperature more rapidly, and will prevent over cooling in very cold weather. This is most desirable for machines used wholly for short runs between which they become cold.


3)    It has been decided to discontinue the fitting of the links between the starter lever and the stand. Machines now being delivered are accordingly sent minus the following parts:-

LE.174    Starter link    (2off)

LE.173    Clevis pin      (4 off)

SL.71/2    Split cotter   (2 off)

When stocks of drilled starter lever assemblies are exhausted the lever boss will not be drilled for the clevis pin.


The cylinder head nuts are made from high-tensile steel and it is important when dismantling for decarbonising or other purposes not to mix these nuts with the standard 1/4" BSF nuts (SL.56/4) used on many other parts of the machine. Standard nuts SL.56/4 must not be used for the cylinder heads.



1)    A large number of 150cc engines have by now been equipped with the conversion type crankshaft assemblies which have the central oil feed jet delivering oil into the centre of the crank disc, and these engines will also have the 34 roller pattern big ends. It is necessary, therefore, to find out the type of connecting rods and sleeves fitted in addition to checking the grade, if new parts are needed, before ordering - See Service Manual. By removing the crankcase oil filter cap and strainer the type of crankshaft can be checked. If there is no jet screwed into the oil pump directing oil against the crank disc and only the oil pipe attached to the pump, a conversion type shaft has been fitted. The parting of the crankshaft assembly and the fitting of sleeves, and rollers etc. can be done by any Agent equipped with Service tools LET.807 and LET.910 and the reconditioning of a conversion type shaft does not entail returning it to us for attention.


2)    The radial holes into the hollow centre of the primary gear shaft are now plugged up making it necessary specially to lubricate the thrust rods during assembly. We use a special lubricant (L.4 Absorbed Oil) which is essential for this particular work, (it must not be used elsewhere on the machine) and we can supply tins containing sufficient for Agents' use at 5/0d. per tin plus packing and postage. This lubricant must be used when fitting the thrust rods to a shaft on which the holes are plugged. It is possible to check whether the shaft is drilled or not without  dismantling the shaft from the box as if the top cover assembly is removed and second gear engaged the plain section of shaft which was originally drilled is easily inspected by turning the shaft.



1)    To prevent oil which leaks along the splines of the gearbox primary shaft escaping into the clutch bell between the faces of the lockring and the clutch bell centre, due to fraze on the inner face of the primary shaft tab washer, the lockring has been modified, and tab washers are now being produced so that the fraze (which is unavoidably thrown up during manufacture) shall be on the side away from the turned over tab. On any machine dismantled, therefore, the tab washer must be replaced and the lockring modified. The lockring is to be modified by turning back the inner face to a depth of 1/32" to a dia. of 0.781" making it into a "washer faced nut", and the lock washer to have a single tab bent over to the side opposite to that on which there is a fraze i.e. In the final assembly the fraze shall be adjacent to the turned back face of the lockring. Further supplies of LE.455 Lockrings, and LE.477/2 Tab washers will be modified to conform to the above requirements. 

 FEBRUARY 1953  


1)    To ensure that more oil is kept in circulation the dipstick LAS.98 has been shortened and the maximum level mark raised. The modified part measures 2.5" from the bottom to the small end of the tapered collar and the level mark is raised to 1/2" from the collar. Dipstick LE.162 (first type without a tapered collar) on 150cc models should also be altered by shortening the stick, and raising the level mark 1/2" The new maximum level mark will take approximately 1.75 pints (0.994 Litre, 1.11 US Pint) of oil for filling.


2)    We are able to supply a neat auxiliary fuel tank to carry and extra 1/2 gallon of fuel. The tank is similar in width and height to the pannier and fits neatly at the rear of the left hand pannier frame. Fitting which quite easy, only requires the drilling of the base of the pannier frame to take 4  - 2BA bolts to hold the tank bracket, and a 1/4" hole in the pannier frame lug to take a bolt to hold the ear of the tank. Whilst the tank is removable, when replenishing the main tank, by using one spanner it is not easily stolen and cannot be drained when in place except by syphoning, making theft of the tank or contents unlikely. In addition we can supply a special right hand pannier frame and bag, longer than the original, which matches the combined length of the left hand pannier and auxiliary tank. The present retail prices (subject to alteration without notice) are:-

LAS.147 Auxiliary tank, LE.519 bracket, fixing bolts and nuts     £1/7/0d

LAS.130/2 Pannier Bag. (purchase tax extra)                               £1/4/6d

LAS.132/2 Pannier Frame.                                                              £0/16/0d

Packing and carriage extra. These may be ordered separately if required.


3)    When reconditioning front fork slider assemblies LAS.49 and LAS.50 these must not be stove enamelled at a higher temperature than 212 degrees Fahrenheit (boiling point of water). This is particularly important as serious damage will be done to the sliders if the temperature is exceeded

 MAY 1953


1)    To assist ordering of spares the following part numbers have been allotted to oversize cylinders as follows:-

        LE.77/3    Cylinder barrel L/H    (150c.c.)    1/2 m/m   (.020") oversize 
        LE.77/4    Cylinder barrel L/H    (150c.c.)    1   m/m    (.040") oversize 
        LE.77/5    Cylinder barrel L/H    (200c.c.)    1/2 m/m   (.020") oversize
        LE.77/6    Cylinder barrel L/H    (200c.c.)    1   m/m    (.040") oversize
        LE.78/3    Cylinder barrel R/H    (150c.c.)    1/2 m/m   (.020") oversize
        LE.78/4    Cylinder barrel R/H    (150c.c.)    1   m/m    (.040") oversize
        LE.78/5    Cylinder barrel R/H    (200c.c.)    1/2 m/m   (.020") oversize
        LE.78/6    Cylinder barrel R/H    (200c.c.)    1   m/m    (.040") oversize

 2)    The manufacturers of the Varley batteries fitted as standard equipment to a proportion of our output have issued a now edition of their Battery Instruction Card in which there are certain modifications to their directions. The gravity of the acid for Temperate climates has been altered from 1.275 to 1.270 (This change of gravity has been made by all manufacturers) and the Tropical climate gravity is now changed from 1.225 to 1.235. Owing to the filters in the Varley special filler cup tending to become choked too quickly with dust and foreign matter they do not now recommend its use but prefer one of the other methods (See LE Service Manual F.456/1R Page 81). The instructions for putting on charge after filling are altered from "Immediately" to "Within 15 hours of commencement of filling" to conform more with instructions for the free-acid type of battery. Their directions for maintenance have been re-phrased and include the following:-

"A teaspoonful to each cell once a month is plenty. After standing for fifteen minutes all surplus liquid should then be removed by siphoning or shaking out if necessary. "Always top up after, and not before, a journey."

 JUNE 1953


1)    Owners of earlier machines equipped with the separate lighting and ignition switches can have their machines fitted with the current type of switch and ammeter if they wish. The conversion is quite easy, and is made by replacing the original legshield top and switches with the later type cover with six position switch and ammeter. Details and current prices are:-

LAS152/2 Legshield Cover, Ammeter and Switch assembly (for B.T.H. Sets)            £1/9/0d

LAS153 Legshield Cover, Ammeter and Switch assembly (for Miller AC.3 Sets)       £1/9/0d

A wiring diagram is sent with each assembly.


Crankshaft and reduction gear plate assemblies are sent to us for reconditioning and modification without the crankcases it is essential that the fitter makes quite sure during re-assembly to the crankcase that no restriction is placed on the flow of oil into the hollow driving shaft. The oil hole in the timing pinion bearing collar must register properly with the hole in the shaft for the full diameter. The key must be in the correct spline to ensure that the collar is correctly located and the collar may require adjusting endwise on the shaft to ensure that the oil holes register for their full diameters. It may therefore be necessary either to grind some material off the face of the collar or shim it to give the correct alignment.

Also for bolting up the reduction gear plate finally into position the bearing collar must be coated with marking and the plate offered up into position without the dowels. By pressing the plate over to one side and rotating the shaft an indication can be obtained of how the oil hole in the bush lines up with the oil groove in the collar and the oil hole can then be countersunk if needed to give free passage to the oil


3)    The tyre pressures in the Owner's Handbook and Service Manual are given as the minimum for solo and pillion work respectively but we find that riders sometimes take these as the maximum and tend to run their tyres under inflated. Riders of heavy build or who frequently carry pillion passengers should be advised that the pressure will probably require to be increased to carry the extra load. The following should be used to find the pressures needed in individual cases:-

Tyre size 3.00 x 19    Load 160 lbs.    Pressure per 17 lbs  

                                         "    180  "              "              "      "   18   "

                                         "    200  "               "             "      "   20   "

                                         "    240  "               "             "      "   24   "

                                         "    300  "               "             "      "   28   "

                                         "    350  "               "             "      "   32   "


4)    Referring to Page 22 of the Owner's Handbook F.437/2R and Page 30 of the Service Manual F.456/1R the Oil pump suction bolt LE.161 is now produced with a groove milled across the head. Careless incorrect replacement of the oil sump filter cap can therefore do no harm except  reduce the volume of oil below the strainer gauze.

 JULY 1953 


1)    In any circumstances when it is necessary to renew the Starter Segment Assembly LAS8/3 and Pinion LE59/4 the working tips of the Starter Pawls must be examined carefully for signs of wear. When new the ends of the Pawls which engage the pinion teeth are machines to 1/32" flat, but after some use may be found to have developed a wider flat. This will prevent their easy engagement with the pinion teeth. If they are found to be worn new Pawls must be fitted otherwise the continued use of the old ones will very soon cause damage to the new Pinion. The replacements must be of the current design, which will necessitate new pivots see March 1953.

These Pawls were first fitted to Engine No.200/18822


2)     First fitted to Engine No.200/19609 a fabric oil filter similar in construction to that which has been used for some time on the MAC model.