Ajs 1933 AJS 33 7 OHC Trophy Owners Manual

A.J.S.Model 33/7

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.

HANDBOOK

for

OVERHEAD CAMSHAFT

TROPHY MODELS 3.46 H.P.

MANUFACTURED BY

PLUMSTEAD, LONDON, S.E.18.

PRICE - ONE SHILLING.

4.95 H.P.

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A.J.S.

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Motor Cycles

O.H.C. TROPHY MODELS

3.46 H.P. and 4.95 H.P.

FOREWORD

In giving the following information we have endeavoured to
meet the needs of all A.J.S. Camshaft Model Owners—that is,
both the original A.J.S. Camshaft machines and the present Trophy
Models. Apart from detail modifications and improvements the
machines are very similar so that this booklet will apply to both
types of machines. On the assumption that the purchasers of
A.J.S. Camshaft Models are already conversant with the driving
of a Motor Cycle we have only included just covering remarks on
this subject. That accessibility has been very carefully studied
in designing A.J.S. machines will become apparent to
of Camshaft Models, when making adjustments of any descrip­tion, so that no difficulties should be experienced in carrying out
the instructions contained in this booklet.

owners

CONTENTS

PAGE

Foreword 1
Driving Instruction 3
Camshaft Engine Details 4
Dismantling and Assembling :—Engine 4, 7, 8 and 9
Engine Lubrication 9 and 10
Dismantling and Assembling :—Gearbox 11 and 12
Clutch and Transmission 12, 13 and 14
Front Chain Cover 13
Carburettor 14, 15 and 16
Lucas Magdyno and Magneto 16 and 17
Ignition Timing 18 and 19
Rear Wheel Removal an

d Adjustment

19 and 20

Front

„ „ ,, ,,

20
Wheel Bearing Adjustment 20
Front Fork Adjustment 20
Steering Head and Handlebars 21
Gear Ratios

.. .. .. .. .. .. .. ..

22

Engine Revolution Chart 22

Guarantee Details .. .. .. .. .. .. .. 23

INDEX TO ILLUSTRATIONS

Camshaft Engine
Timing Charts
Valve Extractor
Valve Grinding Tool
Fabric Oil Filter
Gearbox Adjustment
Clutch
Oil Bath Chain Cover
Amal Carburettor
Lucas Magdyno
Vernier Timing Adjustment
Wheel Alignment Gauge
Steering Head and Handlebars

PAGE

5
6
7

8
10
11

12
13
14
17
18
19
21

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DRIVING INSTRUCTIONS

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a description of the control layout will be helpful and obviate those anxious few moments
when taking over a new or strange machine. First of all the Four Speed Gear Change, if
hand operated, has the following positions: Low or First Gear at the bottom of the Quadrant,
Neutral is next, Second, Third and Top follow on to the top of the Quadrant- With Foot
Operated Gear Change, first of all find Neutral position by moving the Pedal up or down,
then First Gear is engaged by pressing the lever downwards. Second by raising the Pedal,
and Third and Top Gears are engaged with subsequent upward lifting of the Pedal. The
opposite action is necessary to change to lower gears, the correct way of changing to lower
gears being fairly obvious—merely depress the Pedal downwards to the limit of its travel
to engage each lower gear. In the case of both hand or foot operated Gear Change, do not
impose any stress on the lever by attempting to wrench the lever from one position to another,
as by merely pushing the machine backwards or forwards the Gear Lever can be moved
quite easily to any position.

Throttle Control—Right Handlebar opening inwards. Air Control lever—Right Handlebar
opening inwards. Front Brake Control Lever—Right Handlebar inverted lever. Clutch
Control Lever—Straight Pull—Left Handlebar. Exhaust Valve Lifter Straight Pull Lever on
Right handlebar. Ignition Control Lever—on left Handlebar—to advance move inwards,
retard outwards. On electrically equipped models the Dipping and Dimming Control switch
is fitted to left Handlebar.

feel resistance by the float lifting. If Petrol runs out of the Carb. intake turn off the Petrol Tap
before kicking the engine over, but remember to turn this on again after the engine is started.
Starting is much easier if the engine is kicked over once or twice with the throttle wide open,
the air lever closed and the Exhaust Valve lifted afterwards, almost closing the throttle
more than 1/8 when attempting to sta rt the engine.—See Carb. Ins.—Pages 14, 15, 16.

personal requirements, although numerous make this their first job when taking over a new
machine. With the provision made for adjustment of the Saddle, Footrests, and Handlebars
to suit individual requirements it is possible to obtain a feeling of comfort and security.

Assuming that the owner is already conversant with, and can ride a motor cycle,

Handlebar Controls are situated and operated in the following way. Twist grip

Starring.

On the Road.

—Do not overflood the Carburettor, only depress the Tickler enough to

—It does not occur to every rider to adjust the machine to suit his

withdraw the Clutch when changing gear. After a little practice gear changing can be done

Gear Changing.—

quickly and quietly if the throttle is left slightly open and the Clutch is only withdrawn slightly.
The gear lever should then be moved sharply from one position to another.

Braking.—

rear only, invariably leads
considerable pressure to the front brake control without any tendency of the front wheel to
skid, but exercise care on wet or slippery roads, and learn by experiment the maximum amount
of pressure that can safely be applied.

Riders will find that it is not necessary or desirable to completely

Educate yourself to using both front and rear brakes together, using the

to skids on wet roads. On dry surfaces it is possible to apply

—3—

CAMSHAFT ENGINE DETAILS.

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346 c.c. Model—Bore 70 m.m.—Stroke 90 m.m.
495 c.c. „ —Bore 79 m.m.— Stroke 101 m.m.

TAPPET CLEARANCES.

Inlet—16 thou. Exhaust—18 thou. When engine cold.

CAMSHAFT AND MAGNETO CHAIN SIZE.

Number of Rollers—Camshaft a x .230 86

„ „

„

—Mag. Chain a x .230 51

Piston Ring Gap—10 thou.

SPARKING PLUG TYPE AND SIZE.

Competition Engine
Racing Engine

… … … …

… … … … …

COMPRESSION RATIOS AVAILABLE.

346 c.c.
495 c.c.

… … …
… … …

6.8 to 1

6.5 to 1

ENGINE SPROCKETS — No. OF TEETH.

346 c.c. Standard and Racing Solo
495 c.c. Standard Solo
495 c.c. Racing Solo

… … … … …
… … … … …

…

Lodge H.54—14 m.m.

Lodge BR.50—or BR.52—14 m.m.

7.5 to 1

7.5 to

1

… … …

21 Sidecar 18
24 „ 21

25 „ 21

11 to 1
11 to 1

DISMANTLING AND ASSEMBLING : ENGINE

Cylinder Head Removal.—First remove Petrol Pipe. Carburettor complete (as this is

taken from the Cylinder Head remove Knurled ring from top of Carburettor Body and with­draw both slides, leave these attached to their Cables and swing them out of the way).
(Extreme care should be taken not to damage the throttle needle whilst this is exposed);
Sparking Plug, Oil Feed Pipes to Valve Guides, Oil Feed Pipe from main Engine Pump to
Rocker Box and Oil Drain Pipe to Rocker Box Pump, also Exhaust Pipe Locking Ring, etc.
Next remove the four Pins holding the Rocker Box Pump and top Inspection Disc. Take
away the Pump drive and its retaining ring and the Camshaft locknut will then be visible,
withdraw the Cotter Pin from the nut, this can then be unscrewed. Prior to removing the
Pegged Plate which locates the Chain Wheel and Sleeve turn the Engine slowly over until
the top of the Compression stroke is reached; now unscrew the four Rocker Box Pins, and
withdraw the three that are free to come away, then the Rocker box is free, but when taking
this away see that the chain wheel is held in position by the tool provided in the tool kit.
The tubular portion of this can be used for pushing the Camshaft out of the Chain Wheel,
use two chain cover Pins for holding this tool to the chain cover. Six Cylinder Head Bolts
are now visible on top of the Head, also two nuts will be found holding the Cylinder Head
to the Barrel underneath. Remove all of these.

—4—

THE A.J.S. " TROPHY " O.H.C. ENGINE.

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—5—

VALVE AND IGNITION TIMING.

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—6—

The cylinder head can then be lifted up and off. There is no Spigot or washer on

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the Cylinder Barrel, hut the Head must he lifted high enough to clear the two Cylinder Head
studs. If the Cylinder Barrel is removed do not prise this from (he Crank-case but place
the palms of the hands round the finning and rock the Cylinder from side to side and when
it starts to leave the crank-case lift upwards. Do not let the connecting rod fall heavily
against the mouth of the Crank-case or the crank-case f ace will be damaged. When removing
the Piston, only withdraw one Gudgeon Pin Circlip with the special pliers provided and then
either push the Gudgeon Pin out from the opposite side or insert a screw-driver inside the
Gudgeon Pin and bear the screw-driver to one side and turn the Pin slowly out of the Piston
Bosses. The Gudgeon Pin is a sliding fit in the Piston and Small End. When the Piston is
removed either remember the correct original position indicated by the remaining Circlip,
or take a sharp instrument and make a mark on the inside of the piston to indicate front and
back ; be sure to replace the Piston in its original position,

For the removal of the Valves we list a special tool costing 5s. 9d. Part No. XB3340;

and for Valve Grinding a Small Tool costing 1s. 6d. Part No. XB.3360.

The accompanying illustration shows the method of operation of both the valve
extractor and the valve grinding tool; although the Cylinder Head shown does not of course
belong to a Camshaft Model the operation is similar. For portability the valve extractor is
made to fold. Be careful to see that the portion of the toot which depresses the valve spring
collar is central before compressing the spring, otherwise it is almost impossible to remove the
split cones. An important factor to watch when replacing the valve springs is that the
collars are replaced underneath the valve springs. Whilst the cylinder head is dismantled
remove the oil feed nipples to the valve guides to ascertain that these are clear; the inlet
nipple, it will be noticed, is purposely restricted with a disc, so be careful to see that these
nipples are replaced correctly.

Re-assembling—After replacing the Piston, rotate the piston rings in, their grooves
until the respective gaps are at equal distances round the piston, and make sure that the
crankcase washer is still unbroken, otherwise replace. Lead the piston into the cylinder
by holding the piston as far round as possible with the thumb and first finger, at the same
time closing in the rings round the piston. The Cylinder barrel has a chamfer lead-in for
the rings to enter. When the cylinder is again on the crankcase tighten the cylinder nuts
down evenly, not independently.

VALVE EXTRACTOR.

—7—

NO CYLINDER HEAD WASHER IS USED ON THE A.J.S. CAMSHAFT

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ENGINE.

Originally the faces of the cylinder head and barrel are ground in. and providing
they remain clean and unscratched can be replaced without any jointing compound or
attention other than washing with petrol. If however, either of the faces are marked, causing
compression leaks, remove the two holding down studs by two nuts together on the thread

of the stud to unscrew this, then smear the faces with very fine emery paste, and grind in

the same manner as in valve grinding until all the marks are removed. Be sure to remove

all traces of emery paste with petrol after this operation.

Actually it is much better and easier to grind in these faces when both the cylinder
barrel and head are away from the engine; there is then no danger of emery paste finding
its way into the engine and the cylinder head can be rotated freely on the barrel. When the
Cylinder head is again in position, replace the nuts to the studs which protrude through the
cylinder barrel, follow on with the long cylinder head bolts, and lastly, the short cylinder
head bolts. Tighten these down together, not independently. Before replacing the rocker
box make sure that the small hardened caps are fitted over the valve ends, and place the one
rocker box bolt nearest to the exhaust lifter into its hole, then locate the threaded end of the
camshaft into the centre of the chain wheel, afterwards pushing out the tool holding this in
position. Watch that the rubber washer between the rocker box and the chain cover settles
into position properly.

When the chain wheel is in position on the shaft and the rocker box tightened down
it is possible to feel the chain tension. Any excessive slackness after the machine has com­pleted a considerable mileage can be taken up by fitting washers of the correct thickness
under each leg of the rocker box. It is essential however, that approximately 3/8in. or ½in.
of side movement always exists in the chain.

A small plug is situated about half way up the camshaft drive cover: when this is
removed it is possible to insert a narrow screw-driver to ascertain that the tensioner blade
is following the chain and not idle against the side of the cover.

Providing the flywheels have not been rotated the pegged plate can be replaced
through the chain wheel and sleeve, but if the flywheels are not in the original position, turn
the engine slowly over until T.D.C. of the compression stroke is reached: the hole in the
sprocket and that in the sleeve should then coincide although sometimes the shaft has to
be rotated slightly to bring the two into line so as to replace the pegged plate. A rough
check for the valve timing is, that with the piston on T.D.C. and the contact breaker points

just breaking with the ignition lever fully retarded, both the hole in the chain wheel and the
sleeve should be together at 50° to the right from T.D.C.

HOW TO USE THE A.J.S. VALVE GRINDING TOOL.

—8—

When Replacing the Carburettor always rent the slides and cables into position

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before re-fitting this to the engine, otherwise difficulty will be experienced in locating the
throttle needle valve into position in the carburettor. When replacing the carburettor it
will be noticed that no flange washer is used, merely make sure that both the faces are clean
and smear with shellac jointing compound. It is essential to refill or " prime " the oil pipes

with oil when re-assembling the engine to ensure that oil is fed to all bearings when the
Engine is started up. Should it ever be necessary to replace a tensioner blade, first disconnect
all oil pipes and remove the camshaft drive cover ; the drive is then visible. First unhook the
tensioner blade spring at the top, and the blade and spring can then be withdrawn from the
bottom peg; when replacing verify that the spring eye locates in its groove half way along the

bottom peg. The top eye of the spring also fits into a groove in the blade pin at the top.

If it is ever necessary to remove the engine from the frame, time will be saved by

removing the engine and gearbox unit complete. To do this remove the two top front engine

bolts, slacken off the others, take out the two bolts running through the gearbox plates and
saddle pillar down tube, and providing all the other connections have been disconnected
the complete unit can be taken away.

Ignition Timing.—See Magneto and Magdyno.—Pages 18 and 19

valve very slightly from its seat, particularly if a high compression piston is fitted in the engine.

Important.—Only adjust the valve lifter lever cable enough to raise the exhaust

—9—

ENGINE LUBRICATION

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All A.J.S. Camshaft Engines have dry sump lubrication. Oil is fed to Big End of
the Engine and the Rocker Box by the main pump on the Timing Chain Cover. This Pump
also draws oil from the Sump and returns it to the filter in the Oil Tank, an illustration of
which is given below, although this is for another model. By removing the plated hexagon
plug in the top of the Oil Tank it is possible to withdraw the filter for the purpose of cleaning.
To do this immerse the filter in clean Petrol but always make sure that it is thoroughly dried
out before replacing. The filter should be cleaned every 500/1.000 miles. We recommend
that all the oil is drained from the Oil Tank every 4/5,000 miles and the tank replenished with

fresh oil. It is necessary to top up the oil level in the Tank from time to time, and obviously
it is most economical to drain the Tank when the oil is at its lowest recommended level. The
correct Oil level in the Oil Tank being almost up to the end of the return pipe—do not overfill,
otherwise oil will leak from the filler cap—and never let the level fall below the Tank being
half full. We recommend the use of Castrol " R " for Racing purposes and Castrol X.L. for
general and competition purposes.

A small adjustable oil pump is fitted at the top of the Timing Chain Cover: the purpose

of this is to drain the oil from the sump of the Rocker Box and return it to the crankcase sump,

To increase the suction on this, unscrew the lock-nut on the adjuster and turn the
adjuster with a screw-driver in an anti-clockwise direction, and to decrease the suction
vice versa. After making- the adjustment always tighten the locknut. This Pump is correctly

set before the machine leaves the Factory and should seldom if ever need adjustment.

FABRIC OIL FILTER

—10—

GEARBOX

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its lower fixing bolt, and to carry this out the following instructions should be observed:—

chain first slack off the nut on the adjuster bolt nearest the Engine and turn the nut on the
other side of the anchorage in the same direction, i.e., anticlockwise, until the correct chain
tension is obtained. To ascertain this remove the small inspection disc on the front chain
cover, the tension can then be felt with the fingers. It is most important to leave approximately

re-tighten the adjuster nut nearest the Engine and also the centre nut on the gear change
mechanism. Always make a point of adjusting the front chain first and the rear afterwards.
The illustration below shows a similar Pivot mounted gearbox but with hand operated gear
change ; the adjuster referred to, however, is clearly visible.

those of the gearbox index, the short rod between the operating lever on the foot change
mechanism and the striker lever on the gearbox, can be adjusted, as provision is made for this.

the split cotter and yoke end pin from the top of the Short Gear Rod ; if the two are correct,
the holes in the Yoke end and the lever coincide ; that is, when the lever is centralised, as a
small amount of free movement always exists in the lever. Otherwise unscrew the locknut
under the Yoke end and bring the Yoke end into line, afterwards tighten the lock nut and
replace the pins, etc. Only a small alteration to the length of the gear control rod is ever
necessary.

through the kick-starter crank, draw the crank from the splines, take away the Spring cover
and old spring, enter the end of the new Spring into the Gearbox end cover first, utilise a
pair of pliers to spring the end of the Spring into the locating hole in the Kick-starter Shaft.
To increase the spring pressure move the location of the spring end hole by hole in a clock­wise direction until the correct tension is obtained.

The filler Plug is situated on the right band side of the gearbox cover plate. Prior to filling
with lubricant remove the level plug, which will be found about half way up on the gearbox
end cover, then fill until the lubricant starts to run from the level hole, afterwards replace the
level and filler plugs.

Gearbox.—To adjust the primary chain it is possible to swing the Gearbox bodily on

Slack off the centre nut on the foot gear change mechanism and to tighten the, front

a in. or ½ in. up and down movement. After the correct chain tension has been arrived at,

Should the gear positions of the foot gear change mechanism not correspond to

To check off the relation between the two first engage any gear and then remove

Should the Kick-starter return spring ever need replacing, unscrew the Pinchbolt

Replenishment of the gearbox lubricant is very simple and the method fairly obvious.

—11—

CLUTCH AND TRANSMISSION

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The accompanying illustration shows a sectioned view of the Clutch fitted to Cam-

shaft Models. It there is a tendency for the Clutch to slip, make sure first of all that a little

play exists between the Push Rod adjuster and the Push Rod.

Illustration 9.

CLUTCH PARTS.

1.

Clutch Spring Screw.

2.

Main Shaft.

3.

Clutch Thrust Pin.

4.

Main Shaft Nut.

5.

Locking Washer for Main

Shaft Nut.

6.

Clutch Spring Screw Washer.

7.

Clutch Spring Box.

8.

Clutch Spring.

9.

Clutch Spring Box Plate.

10.

Friction Plate.

11.

Clutch Centre Plate Dished.

12.

Clutch Outer Plate.
Clutch Sprocket.

13.

—12—

Clutch Back Plate.

14.
Roller Bearings.

15.
Clutch Spring Stud Nut.

16.
Clutch Centre.

17.
Clutch Spring Stud.

18.
Clutch Rod.

19.
Cork Inverts,

20.

If the adjuster pin bears on the Clutch Push Rod, this prevents the Clutch Springs

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from exerting pressure on the Plates. It is impossible to increase the Spring pressure by tightening
the Clutch Spring Pins, as these are screwed right home, and any undue pressure an these will break
away the heads of the pins.

This can be adjusted with the fingers, but make a point of tightening the locknut, otherwise
the adjuster may vibrate and gradually work hack, eventually causing the Clutch to slip
through absence of play in the Clutch Lever. Although the front chain cover contains an
oil bath, this does not necessarily mean that the clutch runs in oil, if the correct oil level is
adhered to, centrifugal force will keep the oil out of the clutch, although a certain amount
may find its way into the clutch, this in no way impairs its efficiency. Actually the Clutch
is intended to run dry. The method of dismantling the chain cover and Clutch for examination
or Clutch Plate removal is as follows: Remove the footrest arm and Brake Pedal, next the
Pinch Pin at the rear of the aluminium retaining band and the rubber seal strip. The outside
portion of the chain cover can then be drawn away leaving the Clutch, Chain, Shock Absorber
etc., visible. The Clutch Plates can now be withdrawn after removing the six spring bolts,
springs, thimbles and thrust pin. To remove the Clutch Sprocket unscrew the centre nut
from the shaft and the Sprocket will then come away with the Clutch centre. To dismantle
the Sprocket from the centre, unscrew the six nuts securing these two parts, but be aery careful

when taking them apart because there is a Thrust race of Ball and Roller Bearings between the two and
these will drop out if not carefully handled. When re-assembling the Clutch, the Ball and Roller

bearings should be placed alternately round the centre, and to keep them in position smear
them with vaseline or grease after replacing the nuts securing the Sprocket to the centre,
punch and slightly spread the end of the pins in the nuts to make sure that they cannot become
loose. The sequence of the Clutch Plate replacement can be seen clearly from the illus­tration. If the distance Pieces between the two sides of the Chain Cover have been removed
see that these are replaced before re-fitting the outside portion of the Chain. Cover. When
replacing the Rubber Seal strip, smear Shellac Jointing on the inside of this. The ends of
this strip should coincide with the ends of the aluminium retaining strap. Replace the Brake
Pedal before the footrest arm.

In addition to the Clutch Push Rod adjustment, a clutch cable adjuster is provided.

When a chain is joined up with a spring clip, it is most important that the clip is

correctly fitted over the cover plate. The open end should always face in the opposite direction to

which the chain travels. Fit this so that the plate and spring clip are on the inside of the chain,
i.e., next the spokes.

Replacing Chain.—When replacing a chain it will facilitate the fitting of the spring

link if the ends of the chain are encircling an equal portion of the sprocket. This also applies
to removing the spring link.

Back Chain.—Slack off the nuts on each side of back hub spindle and move the

wheel backwards by means of the adjusting screws in fork-ends. Care must be taken to
adjust each side equally or the wheel will be out of alignment (see adjustment gauge. Illus­tration 19). Screw the spindle nuts up tightly again after the chain is properly adjusted.
It may be found that moving the wheel back has caused the brake to be " on. " This is
easily rectified by means of the brake adjustment

—13—

If the chain is too slack it is apt to " whip, " which intensifies the wear and tends to

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break the rollers. If on the other hand it is too tight, a crushing effect is produced on the
rollers, and the whole chain is strained unduly.

The chain should he adjusted and kept adjusted, so that it can be pressed down in

the centre with the finger about ¾ in.

CARBURETTOR

The Carburettor fitted as standard to the Camshaft Models is an Amal. There are

four ways in which the quality of the mixture can be varied, these are as follows :

Alteration of Main Jet size (P) to adjust setting from ¾ to full throttle.

1.
Needle position (C) in Throttle Valve ¼ to ¾ Throttle.

2.

Throttle Valve cut-away on the air intake side (H) ¼ in. to ¾ in. Throttle (num-

3.

bered on top of slide showing variation).

Pilot air adjustment (L) closed to 8 Throttle.

4.

—14—

set, but if the machine is used under varying atmospheric conditions, slight adjustments

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may be necessary. In the first case if starting is difficult and the Engine refuses to " idle "
evenly, slowly screw the Pilot Air Adjuster inwards, but if on the other hand the Engine is
inclined to " eight stroke " at slow speeds, screw the Pilot Air Adjuster out until this disappears,
A point worth mentioning about starting is that the Throttle Stop (illustration) should be set
so as to lift the Throttle Slide slightly off its seat, the twist grip can then be left in the
" closed " position when starting the Engine. The next adjustment is carried out by fitting
a throttle Valve with a different cut-away. If when opening the Throttle spitting back
through the Carburettor, or misfiring occurs, this indicates a weak mixture. To correct this
fit a Throttle Valve with a smaller cut-away.

When the machine is despatched from the Factory the Carburettor has been correctly

openings indicates richness, fit a Throttle slide with a larger cut-away.

the type of Carburettor, and the latter indicating the amount cut-away from the intake side
of the valve in sixteenths of an inch. Thus—6/4, is a type 6 Valve with ¼ in. cut-away.

way; Start the Engine and open the air lever to its fullest extent, open Throttle control
half way and notice whether the exhaust note is crisp and the Engine lively, then close air
lever slightly, if this results in increased Engine speed raise the needle to the next position
in the throttle valve. On the other hand, if the Engine speed does not increase when the air
lever is closed to about half way and the throttle opening increased, or if any tendency to
" eight stroke " occurs, then lower the needle to the next position in the throttle slide. To
alter the needle position pull away the small spring clip locating the needle in the Throttle
Valve and afterwards force this home again. For a Semi-Automatic setting where the Rider
intends to use the Air Lever judiciously and studies extreme economy, lower the needle one
groove further after carrying out this range of tests. For speed work, the Main Jet size may
be increased by 10% as the air lever should always be full open on full throttle openings.

Black smoke from the exhaust or "eight stroking" at low-intermediate Throttle

As a guidance each throttle Valve is stamped with two numbers. The first indicating

The necessity for alteration to the needle position may be checked in the following

STANDARD CARBURETTOR SETTING

Main Jet

size.

33/7 160
33/10 200

RACING CARBURETTOR SETTING

For 59/50 Petrol Benzol and Engine Compression ratio 7,5 to 1.

Main Jet

size.

33/7 52
33/10 58

For Discol R.D.1 Fuel, and Engine Compression ratio 11 to 1.

position.

Cut away.

4/5
4/5

Needle

3
3

1 z
1 x

Bore size.

Cut away.

6/4
6/5

Carb.

Type No.

N.M.8617
N.O.3131

Main Jet

Size,

33/7 55
33/10 65

Valve No.

12
12

Bore Size.

1.06

1.18

—15—

Carb.

Type No.

N.M.7091
M.D.992I

On the Racing Camshaft Models, an Amal Racing Carburettor with Twin Fuel

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feeds is fitted. When tuning this for speed work select the main jet size which gives maximum
power and speed with the Air and throttle full open. The correct size is readily found by
moving the air lever at full Throttle openings : any increase in power obtained by half closing
the air lever indicates that the jet size is too small. Loss of power on closing the Air Lever
slightly shows that the main jet is rather too large. It is far belter to err on the rich side with
Carburettor settings. Weakness " Cooks " Sparking Plugs and other Engine parts.

Idling or slow running is governed by a knurled screw on the side of the Carburettor;
for Petrol Benzol it should be unscrewed about two and a half turns, but for Discol R.D.1
fuel, only about half a turn. Always adjust this control so that a clean pick-up and good
acceleration are obtained. From one eighth to three quarter throttle is governed by the
throttle cut-away; this is indicated in the way explained previously. Three quarter to full
Throttle is governed by main jet size.

LUCAS MAGNETO AND MAGDYNO LIGHTING SET

When Camshaft Models are not fitted with Magdyno Lighting a Lucas Racing
Magneto is fitted. Magnetos have now reached such a stage of perfection that trouble is
seldom if ever experienced with these. Their condition, however, does affect the performance
of the machine considerably. If any trouble is experienced with the Magneto this will usually
be traced to either the High Tension pick-up or the contact breaker. Should starting become
difficult and Ignition is suspected, inspect the following points, remove sparking plug, hold
this against the cylinder with the high tension lead attached to the terminal and kick the
Engine over (be careful to see that the hand is nowhere near the terminal, and that the plug
body makes contact with the cylinder or a shock will be felt) if there is no spark at the points,
take the terminal away from the plug and hold this about 1/8- in. from the Cylinder, at the same
time kicking the Engine over; if a spark is now visible the fault is in the Sparking Plug. Check
off the gap between the points, this should be 20 Thou and if necessary adjust them by either
tapping the electrodes together or springing the outside electrode away with a thin screw­driver. If the plug still refuses to spark, unscrew the centre from the plug body and clean
the mica insulation with a Petrol soaked rag. Make sure when assembling the plug that the
gap between the points is correct. Should it be impossible to obtain a spark from the High
Tension Terminal against the Cylinder, first remove the High Tension Pick-up and examine
this; if any carbon or dust exists wipe this away, also take a pencil or similar object, cover
this with a cloth and insert into the hole left by the removal of the Pick-up, press this lightly
on to the Slip ring, and to remove any carbon which exists rotate the Engine with the Kick
Starter.

Should this not have the desired effect turn to the contact breaker, A Spanner is
provided in the tool kit for adjusting the contact breaker points and removing the contact
breaker centre pin. Take the Contact breaker out bodily by first unscrewing the Contact
breaker Centre Pin and Rocking the Pin from side to side in the centre of the Contact Breaker,
it will then leave the taper hole in the Armature shaft. Now that the Contact Breaker is free
turn the Rocker Arm locating spring and prise the Rocker Arm off its Pin; the Points will then
be visible. If these are pitted or show indications of scaling, file the surfaces of both evenly
with a smooth file, afterwards smooth with fine emery cloth.

When replacing the Rocker Arm on its Pin see that this is an easy fit; a tittle grease
should be smeared round the pin. Be careful when re-fitting the contact breaker to see
that the keyway on the taper of the contact breaker body locates properly in the Armature
shaft before tightening the Centre Pin.

A Gauge is provided on the side of the Contact Breaker spanner for checking the
gap between the points.

Lucas Magdyno.—The previous information covering the Lucas Magneto applies
also to the Magneto Portion of the Magdyno. The Dynamo portion of the instrument is
detachable and can be removed in the following manner :—

—16—

Unscrew Dynamo leads (M and L) Dynamo securing strap (0) and Nut from Drive

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cover, the Dynamo is then free. Wrap some insulating material round lead M, otherwise
the battery will be discharged if the bare end touches any portion of the machine; occasionally
refill the lubricator fitted to the drive cover with grease and screw the cap down. In the
event of the Dynamo ceasing to charge, remove the Dynamo end cover and observe whether
the cut-out closes when the engine is " revved up." If it does not, verify that all three brushes
are settling down on the commutator properly. If after checking alt the leads and connections
as being tight and the dynamo still refuses to charge, take the machine to your nearest Lucas
Depot for attention. Never attempt to push the points of the cut-out together, this will result in a
dead short. If you are compelled to run the engine for any length of time without the Battery,
or if any trouble is experienced with the Dynamo withdraw the brushes from their housings
and clip them under the brush springs or remove the Dynamo altogether until this can be
attended to either by the nearest Lucas Depot or an electrician. Both the Lucas Magneto
and Magdyno are intended to run without attention for at least 10,000, after which the In­strument should be dismantled for the bearings to be repacked with grease.

A—Securing spring for contact breaker cover. B—Contact breaker cover. C—
Fibre heel. D—Contact points. E—Locking nut. F—Adjustable contact point. G—Con­tact breaker fixing screw. H—Locating spring. J—Nut securing brush eyelet, K—Cut-out,
L—Cable to headlamp switch terminal marked FI. M—Cable to headlamp switch terminal
marked +. N—Cable to sparking plug. O—Dynamo securing strap. P—Spring lever
holding brush in position. Q—Carbon brush. R—Pick-up. S—Securing spring for
pick-up. T—Cover. U—Earthing terminal. V—Screw securing dynamo strap. W—Cover
fixing screw.

—17—

Timing.—If the magneto has been removed from the machine it will be necessary

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to see that it is timed correctly after it is refitted.

The sprocket on the armature shaft of the magneto is supplied with a vernier timing

Illustration 5.

VERNIER TIMING ADJUSTMENT.

the timing shifting in the process, as is often the case with other methods. As a means
of verifying the timing, or if the sleeve (1) has been removed from the magneto armature
shaft, set the piston its correct distance from top of compression stroke (see ignition timing
for details), making sure it is not on the exhaust stroke,

adjustment, which allows a very accurate and
certain method of fixing the drive after the
correct setting has been arrived at. The setting
of this vernier adjustment may at first sound a
trifle complicated, hut in reality it is perfectly
simple. Filled to the armature shaft of the
magneto is a sleeve (1), which has thirteen holes
ranged in a circle. Fitting over a collar on this
sleeve is the chain sprocket (2), which has
twelve holes similarly arranged. Now on the
sprocket on engine driving shaft and on the
magneto shaft will be found an arrow. These
must point to each other before anything else is
done. The first thing then in timing up is to
set these two arrows so that they face exactly
towards each other. To do this turn engine
over until the arrow on the driving sprocket is
pointing directly towards the arrow on the mag­neto sprocket. This latter should he held free
in the fingers and moved a tooth backwards or
forwards in the chain until the correct setting
is arrived at. When this is so, place the magneto
sprocket on to the sleeve, and turn the armature
shaft of magneto until a mark found punched
over one of the twelve holes on the sprocket
exactly registers with a similar mark on the out­side of the collar of the sleeve. It will now be
found that the marked holes in sleeve and
sprocket respectively exactly coincide, so that
all that has to he done is to push the peg
washer (3) into these holes, which effectively pre­vents the sprocket from moving from its correct
setting, and tightly screw up the sleeve lock
nut (4), which can be done without fear of

With the piston in this position take off the sleeve lock nut on magneto sprocket and remove
the peg washer. This will leave the armature free from the engine drive, but still connected

CONTACT BREAKER.

—18—

via the chain to the engine. See that the sprockets have their arrows facing as previously

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mentioned. Move the ignition control lever to the limit of its motion of advance. Remove
the cover of contact breaker and slowly turn the armature till the fibre block of the make and
brake lever arises on the inclined plane of the steel segment just sufficient to separate the
points. This is the firing point, and with the piston in the position referred to above the sleeve
and sprocket should register if correctly fitted up. If so, the drive should he fixed up as
before detailed. It is, however, always advisable to check the timing idler tightening up,

must be tightened. The magneto is carried behind the cylinder, on a platform which is
pivoted at its rear end, and can be raised in order to take up any chain slack. To adjust
the chain, the front and rear bolts should be unscrewed a turn or two and the platform raised
from the forward end. When the desired chain tension is arrived at carefully retighten the
bolts.

Magneto Adjustment.—Examine the driving chain occasionally, and, if slack, it

REAR WHEEL ADJUSTMENT GAUGE

held in position by a clip which passes round the tube.

Illustration). When replacing the rear wheel after removal, or after making adjustment
to chain, place the gauge on the rim with the extension to the right, and set the wheel so
that the edge of the gauge just touches the plate that is held by the clip on the chain stay.

On the right-hand side of the bottom chain stay will be found a piece of sheet metal,

In the tool kit will be found a flat gauge that can be fitted round the rim (see

REAR WHEEL ADJUSTMENT GAUGE.

This ensures the wheel being correctly aligned and must be done before finally tightening
up the spindle nuts. Do not attempt to unscrew the clip from the chain stay, as the position
of the plate is set correctly before the machine leaves the factory.

the best method of ensuring this being to see that the hooked end is properly encircling the
bead of the rim. Then pull the gauge end into place firmly.

It is important that this gauge should bed properly on to the rim on both sides;

—19—

DETACHABLE REAR WHEEL

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To remove proceed as follows.—Put the machine on the stand and unscrew the
two pins which hold the stays of the hinged portion of the rear mudguard to the frame. This
hinged portion can now be swung up out of the way. Next, with the special box spanner
provided, unscrew the three sleeve nuts which pass through the hub flanges. To prevent
the wheel revolving while unscrewing the sleeve nuts, place the foot against the tyre at the
bottom of the wheel, or alternatively the change speed lever can be placed in gear. The
three sleeve nuts extend right through the wheel hub flange, and screw on to the three
threaded studs on the driving sprocket. There are also three plain studs on the sprocket
which act as dummy drivers. These fit into the three remaining holes in the hub flange.
After the sleeve nuts have been unscrewed then unscrew the centre pin and draw it com­pletely out, together with the distance piece. The space now left by the distance piece will
allow the wheel to be drawn off the driving studs in the sprocket, and removed from the
fork ends.

To replace the wheel, push it squarely on to the driving studs and next (with the
distance piece in position) screw up the centre pin moderately tight. The three sleeve nuts
can now be screwed up tightly, afterwards giving a final turn to the centre pin. It is very important
to point out that when the centre pin is removed the wheel is hanging on one fork only, so
any rough treatment must be carefully avoided or there is a great danger of damage.

Removal of Front Wheel.—Disconnect the yoke end of the operating rod from the

brake drum lever, remove anchor plate bolt which passes through the lug between the fork
blades, and after slackening off the spindle nuts on either side, the wheel will then fall out
of the slots in fork ends. When the wheel is replaced, see that the brake anchor pin is screwed
in tightly and the spindle nuts are tight.

IMPORTANT

INSTRUCTIONS WHICH MUST BE CAREFULLY CARRIED OUT FOR
DISMANTLING AND RE-ASSEMBLING TAPER ROLLER BEARING
HUBS :—

To dismantle, release the locking nut and screw out the adjusting ring. The dished
plate containing felt washer and plain plate will then drop out. Take out spring ring from
the opposite side of hub and remove felt washer and holder consisting of two plates and
retaining ring, the latter being between the two plates. The spindle can now be pressed or
driven out from either end. bringing with it one of the outer races. The other race can then
be driven out.

To re-assemble, press in outer race on fixed or plain end of hub, taking great care

that it goes in square.

enable the felt washer and its retaining ring together with the two plates to be put in, and
the spring ring to snap into its groove. Care must be taken to put the plate with the larger hole
in last. This is most important. This outer race can now be forced back until the plates
are tight on. the spring ring. The spindle can now be inserted, the short end being placed
in first. The long end of the spindle must be on the adjusting side. The other race can now be
pressed in until there is about z th in. end play in the spindle. Insert plain plate and dished
plate with felt washer, screw in adjusting ring, and gradually screw down until there is just a fraction

of end play in the spindle. This should be .001 of an inch. It is of the utmost importance
that the bearings are not adjusted too tight, as this would ruin them in a few miles.

Having got this adjustment correct, the locking ring can be put on and tightened up, again
taking care that the adjusting ring does not/ creep forward and make the bearings too tight.

This race is pressed in about Q in. beyond its actual position, to

—20—

STEERING HEAD AND HANDLEBARS

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All the 1933 A.J.S. machines are fitted with adjustable handlebars, If the rider
wishes to make any adjustment, slacken off the bolts which pass through the split lugs that
connect the handlebars to the forks, and partly rotate the handlebars upwards or downwards
until the desired position is attained. Afterwards carefully tighten up the bolts of the
split lug.

other article under the engine to take the weight off the front wheel, so that the forks may
move freely.

It is advisable in all cases when adjusting the steering head to place a box of some

SPRING FORK ADJUSTMENT

To take up any play which may have developed in the side links, unscrew the
spindle lock nuts on the right-hand side of the forks (looking at the machine from the front
see Illustration), and turn the spindles by means of the heads on the left-hand side until
all slackness is taken up. Afterwards tighten up lock nuts.

washer and disconnect the anchor plate from the bottom of the steering head. When
reassembling, always screw up the centre bolt before the anchor bolt, to ensure that the
anchor plate seats squarely.

wiping of the friction discs with a rag dipped in petrol. Adjustment is, of course, a matter
of personal preference. However, if the dampers are dismantled at any time, note should
be made of the order of assembly. This is : star washer, spring washer, locking washer
(with raised face outwards), and, finally, hand adjusting wheel.

To dismantle the steering damper, unscrew the control bolt holding the star

The fork dampers require very little attention except, perhaps, an occasional

—21—

GEAR RATIOS

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Competition Models—Wide Ratios.

Engine Sprocket.

Teeth

25

„

24

„

23

„

22

„

21

„

20

„

19

„

18

„

17

Top.

4.51

4.70

4.90

5.13

5.37

5.64

5.95

6.27

6.64

Third .

5.46

5.68

5.93

6.20
6-49

6.82

7.18

7.58

8.03

Second.

7.98

8.32

8.67

9.07

9.50

9.9S

10.50

11.09

11.68

Low.

13.40

13.95

14.56

15.22

15.95

16.75

17.63

18.61

19.70

Racing Models—Close Ratios.

„

25

„

24

„

23

„

22

„

21

„

20

„

19

„

18

„

17

H.P. Racing Model a 25 Tooth Engine Sprocket is fitted. On both the 3.46 H.P, Racing and
Competition Models a 21 Tooth Engine Sprocket is Fitted- For Sidecar work fit a 21 Tooth
Engine Sprocket to the 4.95 H.P. Model and for the 3.46 H.P. a 19 Tooth Engine Sprocket.

On 4.95 H.P. Competition Models a 24 Tooth Engine sprocket is fitted. On the 4.95

4.51

4.70

4.90

5.13

5.37

5.64

5.95

6.27

6.64

5.46

5.68

5.93

6.20

6.49

6.82

7.18

7.58

8.05

6.58

6.86

7.16

7.48

7.84

8.23

8.67

9.15

9.69

11.60

12.08

12.60

13.18

13.80

14.49

15.26

16.10

17.05

APPROXIMATE ENGINE REVOLUTIONS

at different Speeds—Miles per Hour.

Diameter of Driving Wheels, 26 in.

GEAR RATIO.

m.p.h.

5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95

100

3¾

242
485
727

969
1212
1454
1697
1939
2182
2424
2666
2908
3150
3394
3638
3876
4118
4364
4606
4848

4

239
517

775
1034
1293
1550
1810
2068
2327
2586
2845
3100
3359
3620
3879
4136
4395
4654
4913
5172

4¼
275

549
824

1098
1373

1648
1923
2196
2471
2747
3022
3296
3571
3846
4121
4392
4667
4942
5217
5494

4½
291

582

873
1164
1455
1746
2037
2328
2619
2909
3200
3492
3783
4074
4365
4656
4947
5238
5529
5818

4¾

307
614

921
1228
1535
1842
2149
2456
2763
3070
3377
3684
3991
4298
4605

49J2
5219
5526
5833
6140

323
646

970
1293
1616
1940
2262
2586
2989
3232
3555
3878
4201
4524
4847
5172
5495
5818
6141
6464

5

5¼
339

679
1018
1358
1697
2036
2375
2716
3055
3394
3733
4072
4411
4750
5089
5432
5771
6110
6449
6788

—22—

5½
356

711

1066
1422
1778
2132
2488
2844
3200
3555
3911
4264
4620
4976
5332
5688
6044
6400
6756
7110

5¾
372

743
1115
1487
1859
2230
2602
2974
3346
3717
4089
4460
4832
5204
5576
5948
6320
6692
7064

388

776
1164
1552
1940
2328
2716
3104
3492
3879
4267
4656
5044
5432
5820
6208
6596
6984
7372

6

6¼

6½

6¾

7

404

808
1212
1616
2020
2424
2828
3232
3636
4040
4444
4848
5252
5656
6060
6464
6868
7272

420

840
1261
1681
2101
2521
2941
3362
3782
4202
4622
5042
5462
5882
6303
6724
7144

436

873
1309
1745
2181
2618
3034
3490
3926
4363
4799
5236
5672
6108
6544
6980
7416

452

905
1357
1810
2262
2714
3166
3620
4072
4525
4977
5428
5880
6332
6784
7240

GUARANTEE.

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We give the following guarantee with our motor cycles, motor cycle combinations
and sidecars, which is given in place of any implied conditions, warranties, or liabilities
whatsoever, statutory or otherwise, all such implied conditions, warranties, and liabilities
being in alt cases excluded, any statement, description, conditions or representation
contained in any catalogue, advertisement, leaflet, or other publication shall not be
construed as enlarging, varying, or overriding this guarantee. In the case of machines
which have been used for " hiring out " purposes or racing, or from which the trade
mark, name, or manufacturing number has been removed, no guarantee of any kind
is given or is to be implied.

We guarantee, subject to the conditions mentioned below, that all precautions which
are usual and reasonable have been, taken by us to secure excellence of materials and
workmanship, but this guarantee is to extend and be in force for six months only from
the date of purchase, and damages for which we make ourselves responsible under this
guarantee are limited to the free supply of a new part in exchange for the part of the
motor cycle, motor cycle combination or sidecar which may have proved defective.
We do not undertake to replace or refix, or bear the cost of replacing or refixing, such
new part in the motor cycle, motor cycle combination, or sidecar. We undertake,
subject to the conditions mentioned below, to make good at any time within six months
any defects in these respects. As motor cycles, motor cycle combinations, and sidecars.
are easily liable to derangement by neglect or misuse, this guarantee does not apply to
defects caused by wear and tear, misuse, or neglect.
The term " misuse " shalI include, amongst others, the following acts : —

1.—The

attaching of a

damage or calculated to render the latter unsafe when ridden.

2.

—The use of a motor cycle or of a motor cycle and sidecar combined when carrying

more persons or a greater weight than that for which the machine was designed
by the manufacturers,

3.—The attaching of a sidecar to a motor cycle by any form of attachment not
provided, supplied, or approved by the manufacturers, or to a motor cycle
which is not designed for such use.

Any motor cycle or motor cycle combination or sidecar sent to us to be plated,
enamelled, or repaired, will be repaired upon the following conditions, i.e., we guarantee
that all precautions which are usual and reasonable have been taken by us to secure
excellence of materials and workmanship, such guarantee to extend and be in force
for three months only from the time such work shall have been executed or until the
expiration of the six months above referred to, and this guarantee is in lieu and in
exclusion of any common law or statute, warranty, or condition, and the damages
recoverable are limited to the cost of any further work which may be necessary to
amend and make good the work found to be defective.

C ON D I T IO N S OF G UA RA NTE E.

motor cycles, motor cycle combinations, or sidecars, or in any part supplied by way of
exchange before referred to, it must be sent to us carriage paid, and accompanied
by an intimation from the Owner that he desires to have it repaired or exchanged
free of charge under our guarantee, and he must also furnish us at the same time wi th
the number of the machine, the date of the purchase, or the date when the alleged
defective part was exchanged, as the case may be.

Failing compliance with the above, such articles will lie here at the ris k of th e owner ,
and this guarantee and any Implied guarantee, warranty, or condition shall not be
enforced.

We do not guarantee specialities, such as tyres, saddles, chains, lamps, etc., or any
component parts supplied to the order of the Purchaser differing from our standard
specifications supplied with our motor cycles, motor cycle combinations, sidecars or
otherwise.

sidecar to the motor cycle in such a manner as to cause

If a defective part should be found in our

PLUMSTEAD ROAD, LONDON, S.E.18.

Telegrams " ICANHOPIT, WOOL WI CH " Telephone - WO OL WI CH 1010

—23—

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