BSA Ariel 3 1970 User guide

WARNING
If it is required to run the engine above idling
speed when stationary, the driving wheel-must be
raised clear of the ground
H the engine' cover is open take great care that
your fingers and loose clothing;do not contact the
rotating fan blades
J
The fan does not rotate when the engine is
idling.
00-4181
Owners' handbook
5 cm
3
model
B.S.A. Motor Cycles Limited,
Armoury Road, Birmingham,
England Bll 2PX.
Telephone: 021 ,772 2381
Telegramsand
Cables: Selrnoto, Birmingham
B.S.A. Motor Cycles Limited reserve
the right to aIter the designsor any
constructional details of their
manufactures at any time without
giving notice.
Printed in England at B.S.A. Press
October 1970 Copyright B.S.A. Motor Cycles Limited

INTRODUCTION
The Ariel 3 has been designed specifically for inexperienced riders and hence to
run for long periods without major attention. There are no greasing points and
any maintenance that may be necessary is limited to a few items on which
adjustment can be carried out with a minimum of mechanical knowledge.
Study this handbook carefully and carry out the. few maintenance tasks
with faithfull regularity, as detailed in the following chapters, in order to keep
the machine in first-class condition.
By taking a pride in proper maintenance and in the appearance of your
Ariel 3, it will give increased pleasure and retain its original finish and
performance.
In any correspondence connected with your Ariel 3, please quote the
engine and frame number, the former being stamped on the crankcase below the
cylinder barrel, and the latter on the left side of the steering head.
Page 2
RECOMMENDED ENGINE OILS
Castrol Esso Shell Mobil B.P. Texaco
Two- Two- 2TTwo- Mobil Energol Motor
stroke stroke stroke Mix TT Two- Oil
Oil 2T Oil stroke 2T
The above oils, specially prepared for use in two-stroke engines,
mu~t be used m the propo.rtlOn of 1 part oil to 24 parts petrol
eq.Ulvalent to 1/3-pmt- of oil to 1 gallon of petrol (i.e. 4 per cent
mixture).
For running-in purposes only (i.e. for about 1 month or 300
miles) the proporti.on should be 1 part oil to 20 parts petrol
equivalent to 2/5-pmt of OIl to 1 gallon of petrol (i.e. 5 per cent
mixture).
The following oils are also approved for use in the engine:-
Filtrate Plus 2-stroke oil; 1/4-pint of oil to 1 gallon of petrol (1/3-pint of
oil to 1 gallon of petrol for running-in purposes).
Duckhams 2-stroke oil; 1/4-pint of oil to 1 gallon of petrol.
For non self-mixing oils use an S.A.EAO grade in the proportion of 1/4-pint
of oil to 1 gallon of petrol (see notes on page 4).
Page 3

Throttle Control:-This operates the carburetter from the right handlebar grip.
Twist in direction of arrow (D) Fig. 1, to increase the engine speed. The control
may be adjusted for position after slackening the screws (E). The screw (F)
controls the friction damping device within the body, so that the stiffness of
rotation can be set to suit personal requirements.
Decompressor:- This device, used when starting or stopping the engine, is' also
operated by the twist grip on the right handlebar. Turn in the direction of the
arrow (G) Fig. 1, to close the throttle and then rotate further in the same
direction to operate the decompress or, when release of the compressed vapour
will be audible.
THE LEFT HANDLEBAR
Headlight Switch:-The "on/off" switch (K) Fig. 2, can be moved after slacken-
ing screw (L).
Horn Button:-This is included in the same housing as the headlight switch,
at CM).
Rear Brake Lever:- The position of this lever CN) Fig. 2, can be altered follow-
ing the slackening of the screw (P). Tighten securely after adjustment. Grip the
lever to operate the brake. The looseness of the lever is adjusted by rotation of
the screw (R), after releasing its Iocknut.
Parking:-Whenever your Ariel 3 is left unattended, apply the rear brake and
lock in position by means of the latch CS) Fig. 2. To release, grip the brake
lever, withdraw the latch, and secure it in the "safe" position at CT).
Page 6
\
OO~N
~
s. @
T
o y
~
S
FIG. 2.
The controls on the left
handlebar. Note that in
the safe position, the
latch (S) clips on to the brake
lever. The inset shows
brake applied and retained
by the latch.
Carburetter Air Control (or "Choke"):- The trigger-type lever (V) Fig. 2, oper-
ates the shutter at the mouth of the carburetter and can be repositioned only in
conjunction with the rear brake lever. This control provides a rich mixture for
cold starting purposes only. Cable adjustment is described on page 12, and
should be such that a small amount of slackness is present. NOTE:- The trigger
lever CW) is sometimes provided as an alternative to lever CV).
RIDING
RIDING POSITION
Handlebar Height:- The handlebar stem telescopes into the steering head. It can
be raised or lowered after slackening the expander bolt CB) Fig. 3, when it may
also be necessary to tap the bolt head to free the expander cone (C). Tighten
securely after adjustment.
Page 7

FIG. 3.
Handlebar height
adjustment. If the assembly
is dismantled it is most
Important that the cone (C)
is replaced.
Seat Height:-The seat stem telescopes into the frame pillar and is adjustable
for height after slackening the clamping nut CA) Fig. 4. Tighten securely after
adjustment.
FIG. 4.
Seat pillar height adjust-
ment and petroil tap.
The enginecover fasteners
(0) are released with
the aid of a coin.
Page 8
A B
D
RIDING
To Start Off:-Open the fuel tap CC) Fig. 4, and release the parking brake.
Rotate the twist grip control to its limit in the direction of the arrow (0) Fig. 1,
in order to operate the decornpressor, and then pedal the machine in the normal
manner. As soon as it is moving at a moderate speed, grip the air control lever
(V) or CW), as the case may be, Fig. 2, and turn the twist grip in the direction
of the arrow (D) Fig. l , until the decornpressor is inoperative and the throttle
is partially opened, when the engine will start. Immediately the engine is run-
ning, release the air control lever, and.cease pedalling. No're i-c-Excessive use of
·the air control may cause quantities of neat petrol to collect in the crankcase,
making starting very difficult. If the engine is warm, do not operate the air
control lever.
Running:-Control the speed of the machine by means of the twist grip.
To Slow Down:-Gradually close the throttle by turning the grip in the direction
of the arrow (G) Fig. 1, (but not so far as to operate the decornpressor), and
apply the brakes gently.i.Do not apply the brakes sharply «?nwet roads.
.To Stop :-Continue the slowing down procedure until the machine is at a stand-
still, with the engine running slowly.
To Restart:-Release the brakes and gently open the throttle control in the
direction of the arrow CD) Fig. 1. Do not use the carburetter air control, which
is for starting with a cold engine only.
To Stop the Engine:-When the machine is stationary, the engine is stopped by
turning the twist grip control in the direction of the arrow (G) Fig. 1, to operate
the decompressor,
Page 9

Hill Climbing :-On steep hills, the centrifugal clutch allows the engine to run
at its most suitable speed, but it may be necessary to provide pedal assistance
if the gradient is severe.
Engine Failure:-If inadvertently running out of fuel, the drive to the rear wheel
should be disengaged, to allow the machine to be pedalled without resistance
from the engine. Pull out the spring-loaded sleeve (S) Fig. 5A (arrow 1) and
rotate through 90° (arrow 2), where it will be retained automatically by a shallow
slot, Fig. 5B.
To re-engage the drive, rotate the sleeve through a further 90° until the driving
tongues are felt to engage with their corresponding pilot slots. It is then necessary
for the machine to be moved forwards slowly, when the driving tongues will be
heard to engage fully, and the sleeve will return to its normal position, Fig. 5A.
Check the operation and lubricate every three months (800 miles).
FIGS. 5A and 5B.
Disconnecting the drive to
the rear wheel. The left
illustration, Fig: 5A, shows
the normal driving position
and the right illustration,
Fig. 5B, shows the free-
pedalling position.
Page 10
FIG. 5A
FIG. 5B
MAINTENANCE AND ADJUSTMENTS
The whole engine unit is readily accessible for maintenance. First remove the
petroil filter cap and release the fasteners (D) Fig. 4, (both sides) with the aid
of a coin. Open the cover rearwards and retain with the support rod.
Driving Chain:-The slackness in the chain can be gauged with the fingers
following removal of the rubber inspection cap (T) in the chaincase wall. To
remove excessive slackness in the chain, first remove the outer chaincase cover,
then slacken the pivot nut (N) and securing nut (M). Slacken the adjuster lock-
nut (P) and then screw inwards the adjuster bolt (R) Fig. 6 (i.e., turn clockwise).
Total up and down play in the chain should be approximately Vs" (9' 5 mm.).
Retighten the securing nuts firmly. Thoroughly lubricate the chain at intervals
of three months, or 800 miles, with Mobilplex Special.
NOTE:-The chain adjuster bolt (R) should not be confused with the adjuster
(B) Fig. 5A, which is for factory purposes only.
FIG. 6.
Adjustment of the chain drive to the rear
wheel, (shown from below with chain-
case removed for clarity). This operation
will be simplified if the machine is
laid on its right side.
Page 11

Decompressor Cable:-A small amount of slackness must be present, otherwise
the decompressor will be partially open, and starting will be difficult or
impossible.
Removing and Replacing a Brake Cable:- To disconnect a front brake cable,
first reset the adjuster so as to produce the maximum amount of slackness, and
then withdraw the inner and outer casing from tbe abutment on the brake plate.
At the brake lever (position 1, Fig. 8) rotate the cable and nipple until the cable
is in line with the slot in the lever (position 2) and witbdraw sideways (position
3). Use a similar procedure at the handlebar lever.
Pedalling Chain :-Apart from lubrication with Mobilplex Special every three
months or 800 miles, this chain does not require adjustment, any slackness being
accommodated by spring-loaded auxiliary pulleys.
Control Cables:-Adjusters for all cables, i.e., brakes, decornpressor, "choke"
and throttle, are grouped within a detachable box (A) mounted on the steering
column (E) Fig. 7. To reduce slackness in a cable (e.g., to adjust the brake
operation) slacken the locknut (8), hold the body (C) of the adjuster and unscrew
the sleeve nut (D) until the adjustment is correct. Tighten the locknut securely.
FIG. 8.
Removing a front brake cab/e.
The method is the same for the
rear brake cable except that
the lever must be removed from
the brake plate before the inner
cable can be uncoupled.
NOTE--For smooth operation,
all exposed inner cables must
be oiled at weekly intervals.
~
11
B 'I
I,
c
FIG. 7.
Adjustment of the length
of a control cable.
Brake Cables:-All slackness should be eliminated so that the brake is applied
immediately the lever is operated. Make sure that the wheel still spins freely when
the adjustment is completed, and the lever is released.
I,
Throttle Cable:-Adjustment should be such that when the throttle is closed
there is a trace of slackness in the cable. The engine should still Tun slowly, but
if not, screw the adjuster (B) Fig. 11, in or out by a quarter of a turn at a time,
until this condition is achieved. This may require further cable readjustment.
To re-new an inner cable it will be necessary to replace the complete inner
and outer cable assembly. Insert the cables through the .aperture in the steering
head and, for the rear brake cable, lift off the footplate to check that the new
cable follows the same route as the one originally fitted. Adjust as required (see
page 12).
Page 12 Page 13

Tyres and Pressures:-AIl tyres require a pressure of 28 lbs.jsq. in. (2 Kg.jsq.
crn.) which must be checked at weekly intervals. Every three months or 800
miles, the wheels must be removed and replaced in a new position, i.e., left side
wheel is transferred to the right side, right side wheel is transferred to the front.
and the front wheel is transferred to the left side. .
Spark Plug:-To check the firing of the plug, disconnect the cable at the plug
(it is a "snap" fit) and remove the plug. Reconnect the cable, lay the body of the
plug on the cylinder head and push the machine forward for a short distance,
when a spark should be seen at the plug points (Fig. 9). Do not open the throttle
during this operation.
Page 14
L 6ft « 7~S.
c-c»: 7
Ac67f2.n)/JU
FIG. 9.
Checking the firing . <:::)
of the spark plug.
W ~rLK C;vf£J(J
('A. P r:J011 L
At intervals of three months or .800 miles, remove the sparking plug for
cleaning on an abrasive blast machine (possessed by most garages) and have the
po~nts gap set to ·016-· 018"(-40-·45 mm.) by repositioning the side electrode
(Fig. 9). Do not attempt to bend the centre electrode. When a replacement is
necessary, fit Champion L81. .
Petrol Supply:-In the event of suspected petrol starvation at the carburetter
as evidenced by misfiring and lack of power, check the supply of fuel by removai
of the pipe conI ectlOn a~ the carburetter, when the flow should be plentiful and
contlDl}ous. This operation will be Simplified If the bolt clamping the carburetter
to the inlet pipe IS slackened and the carburetter rotated as required. If the flow
FIG. 10.
Checking the
petrol supply.
Page 15

is intermittent, or none at all, lay the Ariel 3 on its right side, disconnect the I
pipe at the tap and unscrew the tap complete. Clean the filters (A) and CB), tap
(C), and pipe line (D) Fig. 10, and replace. (See also "Carburetter Jet"). I
Carburetter Jet:- The jet (A) Fig. 11, is readily accessible for cleaning in the
event of blockage and consequent fuel starvation, and its removal does not neces-
sitate dismantling the carburetter. Unscrew the jet with a suitable spanner and
blow through the orifice until it is certain that it is clear of any obstruction. Make
sure that the obstruction has not been transferred to the smaller side holes. Do
not use any sharp implement for cleaning purposes and do not over-tighten when
replacing.
The spring-loaded screw (B) should not be touched since it is concerned solely
with adjustment of the throttle for satisfactory engine idling (see throttle control
cable, page 12). .
FIG. 11.
Removal of the
carburetter jet
for cleaning.
/
1
The Air Filter:-The carburetter air filter (Fig. 12) must be removed and
thoroughly cleaned at intervals of not more than one month (or 300 miles),
otherwise the air supply to the carburetter will be reduced, causing heavy fuel
consumption and poor performance.
FIG. 12.
Dismantling the
air filter.
Push aside the wire clip (G), and lift off the air silencer body (H). The air
filter (1) and its sealing ring (K) can then be withdrawn. Wash the filter thoroughly
in neat petrol, afterwards adding cycle oil sparingly. Clean the silencer and re-
assemble.
Wheel Removal:-The wheels are quickly detachable and also interchangeable.
They are attached to the brake drum, but removal does not affect brake adjust-
Page 17
Page 16

ment. Unscrew the three nuts CA) Fig. 13, to release the wheel. Note that these
nuts are of the self-locking type and any replacements must be of the same
description.
FIG. 13.
Removing
one of the
wheels.
ELECTRICAL· EQUIPMENT
Current for the lighting system and the horn is provided by the generator on the
engine shaft and hence the lamps will not be illuminated nor the horn useable
when the engine is stationary.
To adjust the vertical angle of the beam, slacken the screw beneath the lamp
and tilt the lamp to obtain the correct setting.
NOTE:-Lighting regulations vary with different countries and it will be advis-
able to check that your beam setting complies with the requirements.
FIG. 14.
Adjustment
of the steer-
ing head
beatings. FIG. 15.
Replacing
the headlight
bulb.
The Steering Head :-Check the head bearings regularly for slackness. The
handlebars should rotate smoothly and freely, but without up and down play.
If adjustment is necessary, slacken the locknut (L) Fig. 14, and tighten the ring
nut (N), until the above condition is obtained, afterwards retightening the locknut.
It is essential. that the ring nut is not over-tightened otherwise the steering will
become stiff and the ballraces damaged.
Page 18
( .•
FIG. 16.
Replacing
the tail
light bulb.
The headlight bulb is a C.E.V. 6 volt, 15 watts. To replace, remove the screw
(F) Fig. 15, and take off the top cover of the lamp. The spring cont~ct blade (G)
can then be pushed aside and the bulb CJ) Withdrawn from Its housing. Do not
bend the blade backwards otherwise there will be faulty contact at the bulb.
Page 19

1
The rear light- bulb' is -3: festoon type, 6 volt, 6 watt, type Alite A317. To
replace, remove the screws (H) Fig. I?, and detac~ the lens. Take care not to
strain the bulb holder strips.(K), otherwise the electrical connection may become
unsatisfactory.
Replacement bulbs can be' obtained from your local B.S.A. Service Dealer.
The Contact Breaker Points:- The gap between the contacts tends to widen a~d
the faces to become dirty. It is essential that these are kept clean, otherv.:lse
starting may become difficult. Attention is advisable at intervals not exceeding
six months (or 1,500 miles).
Support the engine unit on a box, open the engine cover, and remove the
right wheel. Alternatively, the machine may be laid on its left side. .
Take off the flywheel cover (F) which is ·retained by two spring nngs (0).
Turn the flywheel until one of its apertures is opposite to the contact points and
the gap between them is at its maximum (Fig. 17): Only one of the three aper-
tures will meet this condition. Now clean the points with a cloth moistened III
petrol.
If the required gap of ,016"-,018" ('40-'45 rnm.) is incorrect, slacken the
fixing screw CH) by half a turn, insert a screwdriver blade between the two .bosses
(K) and into the slot (S) on the carrier plate and slif;htly twist the screwdnver to
modify the gap to the above figures. TIghten the fixing screw and check the gap.
Page 20
DEALER MAINTENANCE
FIG. 17.
Adjustment of the
contact breaker points.
Thirty days (or 300 miles) after you bave taken delivery of your Ariel 3,
return it to your B.S.A. dealer for inspection in accordance with the details given
on the Guarantee (Warranty) Registration Card. ., .
, At intervals of not more than twelve months or 3,000 miles, It ISsuggested
that the following maintenance work is carried out for you by a B.S.A. Service
Dealer but for owners who have some mechanical knowledge and wish to do
the wo~k themselves, no difficulties should be encountered if the instructions
given in the Workshop Manual are closely followed. .
Decarbonising:- This process concerns the removal of the carbon deposits inside
the cylinder head, ports, exhaust system, etc., caused by combustion of the pet~OIl
mixture. If decarbonising and cleaning the silencer is neglected, excessive falling
off in power, over-heating and other troubles will be caused.
Page 21

Bearings:-For all wheels it will be necessary to dismantle the hub completely in
order to replenish the bearing housing with grease. Similarly, the large pulley
spindle assembly will require dismantling for attention to the bearings.
Ignition Timing:-This is set at 2-2·2 mm. before top dead centre. Renewal
of the contact breaker set should be followed by a check on the ignition
timing, for which purpose the contact assembly plate has a limited range of
adjustment. In any case, the ignition timing should be checked at the above
mileage. .
FAULT-FINDING CHART (1)
Engine will not Start
I
Decompressor stuck open
(audible; release and lubricate)
I
I
No Petrol at Carburetter
I
Tap closed (open tap)
I
Tank empty (replenish
tank; page 4)
I
Choked filler cap vent
(clear obstruction)
I
Choked pipe, tap or filter,
(clear obstruction;
page 15)
I
Petrol at Carburetter
I
I. I
No Spark at Plug Excessive use of
I carburetter air
Plug oiled up (wash I control causing neat
in petrol and dry out) petrol to enter crank-
I case
Plug points bridged --- I
with foreign matter <Chafed cable causing
(clean and retest) short circuit (replace
I cable)
Damp or cracked
plug insulation (dry
out; replace if
cracked)
I
Dirty or incorrect
contact points gap
(clean and adjust;
page 20)
Contact Breaker Cam:-The lubrication pad is thoroughly soaked in grease
before assembly, but it will be advisable for it to be regreased when the ignition
timing is checked.
Steering Head:- The assembly must be dismantled in order to re-grease the
bearings. At the same time check the ball tracks, replacing the cups and cone
if showing signs of indents.
Page 22
I
Genera tor failure
(replace generator)
I
Spark at Plug
I
Plug may not
spark in situ.
(Clean and retest,
or fit new plug)
Page 23

FAULT-FINDING CHART (2) INDEX
Faulty Running of Engine
I
Incorrect petroil mixture
I
Page Page
AIR FILTER ..
17
FAULT-FINDING CHARTS
23,24
CONTROL CABLES:
Brake cables-adjustment
12
MAINTENANCE AND
Brake cables-replacement
13
ADJUSTMENTS
11
Throttle cable-adjustment
12
Decompressor cable-adjustment
13
PETROL SUPPLY:
Clearing obstruction
15
CARBURETTER:
Cleaning jet
16
RIDING:
CHAINS: Starting etc.
9
Driving-adjustment
11
Pedalling
12
RIDING POSITION:
CONTROLS: Handlebar and
seat
heights 7
Setting 5
DEALER MAINTEJjlANCE
21
RUNNJNG-IN
4
ENGINE: SPARK PLUG
14
Lubrication 4
Failure
10
STARTING
9
ELECTRICAL EQUIPMEl\'T:
Headlight-adjustment
19
TYRES
14
Headlight-bulb replacement
19
Rear light-bulb replacement
20
STEERL1'./G HEAD
18
Bulb types ..
19,20
Contact breaker-adjustment
20
WHEEL REMOVAL
17
Page 25
I
Misfiring
I
Dirty plug (clean or fit new plug)
I
Dirty contact breaker points clean and
adjust gap, page 20)
I
Incorrect opening of contact breaker
points (adjust gap, page 20)
I
Water on high-tension cable dry out)
I
Water in fuel drain tank. strain, and
replenish)
I
Dirt in carburetter jet (dismantle and
clean-out, page 16)
I
Partial fuel obstruction (dismantle fuel
line, etc., and clean out, page 15)
I
Lack of Power
I
Incorrect ignition timing (reset)
page 22)
I
Exhaust system choked (decarbonise,
page 21)
I
Fuel supply obstructed (dismantle fuel
line or blocked carburetter
jet and clean out, page 15 and 16)
I
Brakes binding (readjust cables, page 12)
I
Chain 1 tight slacken off at adjuster,
page 11)
Page 24