JAWA babetta 28 User guide

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SERVICING AND MAINTENANCE INSTRUCTIONS
Ultra - Lightweight Motorcycle - type 28
C
y
linder ca
p
acit
y
49 cm3
En
g
ine out
p
ut 1,5 HP at 4500 r. p. m.
Maker Považské strojárne,
Považská Bystrica
Ex
p
orter Motokov - Prague - CSSR
The moped is the motor vehicle having a very
simple service and maintenance due to its
automatic clutch and one-stage gear box. Despite
of this the careful study of this booklet is
recommended to your before its use in order to get
acquainted with its servicing and maintenance.
Thus many failures will be avoided and the moped
will serve you to your full satisfaction.
Much pleasure and many satisfied kilometers
with the moped. Považskè strojárne
Považská Bystrica
All rights of design alteration resulting from the
moped development, as far the illustrations and
the description given in this booklet are given, are
reserved.
Fig. 1. Babetta Moped – Main Parts
1. Tail lamp 2. Rear mud guard. 3. Pump.
4. Luggage carrier. 5. Bag with tools. 6. Seat.
7. Suction filter. 8. Fuel tank. 9. Fuel tank plug.
10. Handlebars. 11. Headlamp. 12. Frame.
13. Front fork. 14. Front mudguard. 15. Rear
wheel. 16. Exhaust silencer. 17. Chain of engine.
18. Pedals. 19. Chain of pedals. 20. Stand
21. Engine disengaging. 22. Alternator (under
cowl). 23. Exhaust knee piece. 24. Engine.
25. Spark plug with cable shoe. 26. Front wheel.
Table of Contents
I. Technical Data 6
II. Control elements and their servicing 9
III. Riding instructions 11
IV. Maintenance and adjustment of vehicle 18
V. Tools 38
VI. Defects and their remedies 39
VII. Spare parts 44
I. TECHNICAL DATA
Type of engine - two-stroke, air-cooled, single cylinder
Cylinder capacity - 49 cm3
Bore of cyl. x piston stroke - 39 x 41 mm (1.55 x 1.61")
Compression ratio - 1 : 6.5
Output - 1.5 HP, 4500 r. p. m.
Clutch - dry, automatic, centrifugal
Gear box - one stage
Overall gear ratio to rear wheel - 1 : 15.75
Ratio of pedals to rear wheel - 1 : 0.568
Starting - by means of pedals
Front springing - telescopic fork without shock absorber
Stroke of front springing - 60 mm (2.36")
Brakes - drum shoe brake operated by the levers on the
handle bars
Brake size – 85 X 20 mm (3.35 X 0.79")
Tyres – 23 X 2"
Inflation of tyres: Front - 1.5 - 1.75 atm. eff. (24 psi)
Rear - 2 - 2.25 atm. eff. (30 psi)
Weight of vehicle - 42 kg (92.6 Ibs)
Carrying capacity - 90 kg (220 Ibs)
Velocity - Permanent - 35 km/hr. (32 m. p. h.)
Maximum - 40 km/hr. (25 m. p. h.)
Fuel tank capacity - 3 litres (res. 0.5) 2.64 Imp. pt. (0.88)
Maximum climbing ability - 10 %
Noise level - 73 dB
Lgnltlon - contactless, by means of semicoductors
Sparking plug - PAL 14-5 R
Headlight - 21 W, 6V
Rear light - 5 W, 6 V
Bell - smooth
Basic fuel consumption- 0.37 galls/62 miles (1.7/100 km)
by 16 miles/hour (27 km/hour)
Page 1 Babetta type 28 owners handbook pages 1 to 7 jkw

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II. VEHICLE CONTROL ELEMENTS
The moped is easy to operate and for its
servicing:
Are required the following elements only:
a) Throttle twist grip (1, fig. 2) the rotation of which
disengages and engages automatically the clutch
by releasing and throttling the gas and further this
is used to regulate the velocity of vehicle.
b) Front brake (2, fig. 2) and rear brake (3, fig. 2)
levers by means of which the moped is braked and
stopped
c) Decompressor lever (4, fig. 2) by means of
which the engine is stopped or the start is
facilitated.
d) Buzzer push-button (5, fig. 2)
e) Dip switch (fig. 3). The buzzer and the front and
rear lights may be in operation during the engine
function only.
f) Fuel tap (fig. 4)
g) Air closing push button (fig. 5)
h) Pedals (fig. 6)
i) Disengaging the engine (fig. 7)
Fig. 2. Steering of vehicle
1 Gas grip, 2. Front brake lever, 3. Rear brake
lever, 4. De-compressor lever, 5. Bell
Fig. 3. Switch of lights
(in the lower part of headlamp)
Fig, 4. Fuel tap 0-opened fuel supply, R-reserve
Running-in new motorcycle
Thoroughly run-in new moped influences its
output, consumption and service life. Take into
consideration the following instructions when
running-in:
a) Drive mixture - M2T oil with 80 octanes petrol be
mixed in ratio 1:25,
b) This ratio keep during the running-in (500 km
abt.),with maximum opening half rotation of throttle
twist grip (speed abt. 20 km/hr.),
c) When longer drives we recommend to lubricate
the engine by opening he throttle. When riding
downhill we do not recommend to throttle the gas
but to use the rear brake.
d) When stopping let the engine run at idle speed
and ovoid to open the throttle uselessly.
III. RIDING INSTRUCTIONS
Check before the drive
- the correct function of brakes
- the inflation of tyres
- fuel level in the tank
- the function of buzzer and lights (during the
engine run)
Filling the fuel tank
As the fuel is used the petrol mixed with oil.
Maintain the specified ratio of oil and petrol, at the
fuel pump take this ratlo, is observed; Use as a
minimum 80-octanes petrol. The tank is to be filled
with the funnel provided with strainer.
Starting the cold engine
Open the fuel tap (fig. 4) press the push button of
air closure (fig. 5) up to contact (after depressing
the pin jumps out, the air, however remains shut)
There are two kinds of starting the engine. Starting
the cold engine during the summer period.
Fig. 5. Air closing push button
Page 2 Babetta type 28 owners handbook pages 8 to 14 jkw

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Starting the cold engine during the summer
period
a) start on stand: this is made in such a way the
moped is put on the stand, the oir closure push
button arranged on the carburettor is depressed,
the decompressor lever is depressed the gas grip
is rotated to ½ of gas grip rotation range, the pedal
is put.abt, 30º from the perpendicular position in
the direction forward, the pedal is kicked suddenly
and before the final kicking the pedal into lower
dead posltion (when the engine has the sufficient
speed) the decompressor lever is released. The
engine start to work Repeat this if required. After
starting it is necessary to let the engine to warm
up, after warming up rotate the gas grip up to
contact due to what the air closure valve of
carburetor is opened. By rotating the gas grip
backward the engine works on idle run and it ls
ready for the drive. The vehicle is put from the
stand on the wheels and by releasing the gas the
start is effected.
b) Start by kicking: The vehicle is put on the
wheels, the air closure push button on the
carburettor is depressed, the decompressor lever
is.depressed, the gas grip as in the point a) is
rotated. The vehicle is put in motion due to kicking
and when the sufficient velocity is obtained the
decompressor lever is released, the motor starts
and by releasing the gas its velocity is increased. If
required during the drive, especially when drive
uphill the engine may be aided by kicking the
pedal.
Fig. 6. Starting the engine
Start of warm engine (after shorter drive
interuption).
The methods mentioned under a) and b) may be
used. It is not necessary to depress the air closure
on the carburettor.
Start of engine during the cold weather (in the
winter)
When the temperature of atmosphere sinks below
0º C the start is to be effected as follows:
Start is made as under point a) with that difference
before the start the pedal is to be kicked several
times to loosen the individual mechanisms which
stiffen due to the cold. One can help out by
depressing the decompressor lever.
The start itself is effected as under point a) (with
that difference the gas grip is rotated to ¾ of range
- the air valve should not open). The number of
kickstarts increases proportionally to the sinking
temperature of atmosphere. The method of start
under b) on the ice covered roads is not
recommended for the safety reasons.
Fig. 7. Disengaging the engine
Braking and stopping
In the case the braking is required release the gas
grip with brake levers (2,3 fig.2) and brake
down.One proceeds in the same way when
stopping the vehicle. The clutch disengages due to
the velocity decrease and the engine works on idle
run. If the drive is continued due to the releasing of
gas the clutch is engaged again and the vehicle is
put in motion. After finishing the drive the engine is
to be stopped by depressing the decompressor
lever (4, fig.2) and shut the supply of fuel by
rotating the fuel tap lever (fig.4) to the position C.
The position of lever B is the reserve and it is
sufficient for the drive of abt. 30 km.
On the moped as on the cycle
If you want to use the moped as the cycle (e.g.
when consumption of fuel) depress the
disengaging device of engine – the star-like nut in
the direction in the engine and rotate to the right
(fig.7). the nut remains fitted into this position and
the engine remains disconnected. The engine is
engaged again when you depress again the star-
like nut in the direction into the engine and rotate it
to the left.
IV. MAINTENANCE AND ADJUSTMENT
Maintenance of vehicle
When cleaning the varnished and chrome plated
vehicle parts use always the water and saponates.
After washing the varnished and chrome plated
parts wipe them with buck leather. The plastic and
rubber parts of air filter are to be washed by the
water only. The varnished and rubber parts and
plastics do not wash by kerosene, petrol or another
diluent since these parts could be deteriorated,
Page 3 Babetta type 28 owners handbook pages 15 to 20 jkw

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Fig. 8 Air filter
The air filter element (fig. 8) is to be washed from
time to time in petrol. Clean from to time the hole B
of exhaust silencer (fig 9) from the carbon. When
bigger decrease of output check whether the
exhaust silencer is not choked by the carbon. The
exhaust end piece is able to be pulled out after
screwing out the nut A.
Fig. 9 Exhaust silencer
The oil in the gear box is to be changed after the
ride only, when the oil and the engine are warm.
Unscrew the discharge screw from the engine
bottom part (2, fig.11). After discharging the oil it is
suitable to wash the gear box by the rinse oil. Fill
the new gear oil through the filling hole 1 up to
control orifice 3. From time to time check the oil
level in the gear box and refill if required.
Fig. 11 Filling and discharging oil screw
1. Filling hole screw, 2. Discharge oil screw
3. Control hole
Fig. 10 Lubrication of vehicle
Lubrication Table (fig. no. 10)
Fi
g
. Lubrication
p
oint Lubricant kind Notes
1En
g
ine oil for two stroke
p
ermanent lubrication,
engines SAE 30 M2 T Oil and petrol ratio 1:30
2 Gear box gear oil charge 0.02 galls, (0.13 lt)
SAE 30-80 (PP 80)
3 Steering bearing grease wash and grease
(AV 2) when dismantling
4 Gas twist grip grease (AOO) apply on the sliding
parts after washing
5 Brake and decom- oil SAE 30
pressor levers (M 6A)
6 Bowdens thin oil fill in bowdens
7 Wheel bearings bearing grease (AV 2) refill in bearings
8 Brake cam pin, cams, grease (A 00) grease with small
brake shoe pins quantity after cleaning
9 Chains graphite oil, clean and grease as
grease (A 00) required
10 Stand pin oil SAE 30 (M 6A)
11 Pedal bearings oil SAE 30 (M 6A)
12 Front telescopic forks oil SAE 30 (M 6A)
13 Idling run wheel oil SAE 30 (M 6A)
Page 4 Babetta type 28 owners handbook pages 20 to 24 jkw

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VEHICLE MAINTENANCE SURVEY
After driving
first 800 km (500 miles)
- change the oil in the gear box
- adjust and clean the carburetter
- tighten the cylinder head nuts
- tighten the seat nuts
- adjust and grease the chain
- adjust the brakes
first 1500-2000 km (930-1300 (miles)
- decarbonize the exhaust silencer and exhaust
knee piece
first 2000 km (1300 miles)
- change the oil in the gear box
- clean the carburetter
- clean the suction filter element
- adjust and grease the chain
- adjust the brakes
- check the tightening of screws
- check tightening of nuts and spokes of wheels
- grease the bowdens
every 6000 km (4000 miles)
- clean and check the spark plug
- change the oil in the gear box
- clean the carburetter
- clean the suction filter element
- adjust and grease the chain
- adjust the brakes
- check the tightening of screws
- check tightening of nuts and spokes of wheels
- grease the vehicle
Idling run wheel chains greasing and cleaning
the brakes be effected more oftenly if rainy
weather. The other maintenance including the
greasing is to be effected as required.
Fig. 13 Adjustment of handlebars height
Adjustment of height of seat and handlebars
The height of seat and handlebars may be
adjusted by the driver as required. The inclination
of seat is adjusted after loosening of nut A (fig.12).
The tightening of nut A is to be checked from time
to time to avoid the tear of holder teeth. The height
of seat is adjusted after loosening of nut B. This is
able to be adjusted in the limits of 120 mm. The
height of handlebars may be adjusted after
loosening of screw A and both nuts B (fig.13)
within the limits of 100 mm. After adjustment of
seat and handlebars the nuts and the screws are
to be tightened thoroughly.
Fig. 12 Adjustment of seat
Adjustment of brakes
For the current adjustment of front and rear brakes
are used the screws arranged on the handlebars
(fig.14). When adjustment loosen the knurled nut
(1) and by screwing in or out the screw (2) is taken
up the clearance of brake lever so that after the
compression the lever is distant from the handle 20
to 30 mm. After adjustment of brake the nut (1) is
to be tightened.
If the brakes are not able to be tightened by the
screws arranged on the handlebars these may be
adjusted on the brake cams, (fig.15 and fig.16) by
tightening the brake cable. Then the final
regulation of brake adjustment is to be effected by
the screws arranged on the handlebars.
Check after adjustment of brakes whether these
are not tightened too much. Put the moped onto
the stand and ascertain by rotating the wheels
whether these rotate freely without the jerks.
Fig. 14 Adjustment of brakes
Fig.15 Adjustment of front brake
Page 5 Babetta type 28 owners handbook pages 25 to 30 jkw

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Adjustment of chains
The chain of the engine is adjusted after loosening
the nut of rear axle (3 fig.16). By tightening the
nuts of chain tightener (2) on both sides of frame
tighten the chain so it has the clearance of abt.
10mm after the compression. After the adjustment
of chain check the trace of the wheels by means of
straight lath ond tighten thoroughly the nuts of the
axle. The chain of the pedals is adjusted by means
of tension pulley arranged on L. H. side of the
moped (fig. 17).
Fig. 16 Adjustment of rear brake and engine
chain
Fig. 17 Adjustment of chain of pedals
Fig. 18 Adjustment of decompressor
Decompressor adjustment
The decompressor is adjusted after loosening the
screw A (fig.18) on the decompressor lever. The
cable is loosened or pulled so the clearance of
bowden from the stop B is 1 - 1,5mm (fig.19).
Tighten the screw after adjustment of clearance of
cable.
The clearance of the cable must have the
prescribed value since at the tightened cable
the burning through of decompressor valve
would take place. The decompressor does not
function with the free cable.
Fig. 19 Checking the decompressor adjustment
Fig. 20 Carburettor 1. Saturator pin. 2. Mover
stop screw. 3. Regulating screw for richness of
idle run mixture.
Carburettor (Fig. 20)
When failure of carburettor we would like to
recommend you to apply to the service repair shop
which effects the repair, adjustment and cleaning
of the carburettor. The nozzles are to be cleaned
by the petrol and compressed air only. Jikov 2909
DC carburetor has the following equipment and
adjustment used for Babetta moped:
-main nozzle 63
-idle run nozzle 35
-mover needle adjusted on 2nd. Notch from
upward
-regulation screw of mixture richness for idle
run loosened backwards througn 1½ rotation.
The stop screw of the mover is used for
adjustment of idle run r.p.m. The speed
increased by screwing in and decreased by
screwing out.
Fig. 21 Adjustment of carburettor
Page 6 Babetta type 28 owners handbook pages 31 to 36 jkw

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Ignition
The moped is equiped with contactless
semiconductor ignition which does not require any
servicing and maintenance except the temporary
cleaning of plug and the failure may take place
only due to the not qualified intervention by the
user. No advanced ignition is required to be
adjusted since no mechanical wear takes place.
The advanced ignition is to be adjusted after
loosening the screws of stator only or after
dismantling the alternator. We recommend you
therfore not to intervene into the adjustment of
ignition. In the case of failure apply to the
specialised repair shop.
Fig. 22 Adjustment of advanced ignition I
When adjustment of advanced ignition the rotor is
to be rotated in the direction of arrow A (fig.22) till
coincide B-lines of rotor and stator. Insert the dial
indicator or depth gauge into the plug hole and
measure the depth of insertion. Then rotate further
the rotor in the direction of arrow A up to the upper
piston position. The distance on the dial indicator
from the coincidence of the lines up to the upper
dead center should be 1 - 1.5 mm. If this value is
higher, loosen the screws E (fig.23) and rotate the
stator in the direction of arrow C, when lower value
rotate the stator in the direction of arrow D.
This operation is to be effected so till the value of
advanced ignition of 1 - 1.5 mm is reached. After
adjustment tighten thoroughly all screws and check
the correctness of adjustment again.
Fig. 23 Adjustment of advanced ignition II
V. TOOLS
The tools are accomodated in the bag arranged
under the seat. The content is:
combined spanner
screwdriver 3 mm
spanner 10 mm
spanner 19/21 mm
handle Ø 5 mm
handle Ø 6 mm
lock
pump (is accomodated under the luggage carrier)
VII. SPARE PARTS
The serial number of vehicle and the manufacture
year are shown on the name plate accomodated
on the front part of frame. The engine number is
stamped on the engine box. The serial number is
intended for the registration of moped. When
ordering the spare parts from the sales agent or
from the sales shop give always this serial number
and manufacture year of moped. The moped
holders are recommended to keep the following
spare parts:
Refer. No. Name of
p
art
28-5240 Gas bowden com
p
lete
28-5247 Rear brake cable
28-5256 Front brake coble
28-5265 Decompressor cable
60304 Headlamp bulb
PS25-1, 6V, 2W Ba15s
60600 Tail lamp bulb
C11, 6V, 5W, SV8.5
62088 Sparking plug 14-5 R
55017 inner tube 23X2"
28-7227 Petrol hose
Published: After-Sale Service Department,
Považské strojárne,
n. p., Považská Bystrica, Czechoslovakia
Page 7 Babetta type 28 owners handbook pages 37 to 40 & 46 jkw

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VI. DEFECTS AND THEIR REMEDIES
Discovered failure Remedy
Engine missfires
Engine overheats.
Plug electrodes are overheated, the faulty
plug (not corresponding thermal value).
Too much carbon in the cylinder head and
in the exhaust duct.
Big advanced ignition.
Exhaust silencer choked.
Wait till the engine is cooled do not run at high speed.
Change the plug.
Remove the head and dismantle the exhaust, remove
the carbon.
Regulate the advanced ignition.
Dismantle the silencer & clean it.
Engine knocks
Correct
spark
Water or oil in carburetor.
Insufficient fuel supply into carburettor.
Leakage in the crank case
Poor mixture (white exhaust gas)
Clean the carburetor.
Open fully the fuel tap (especially the reserve), refill
the fuel, check the supply piping, clean the aerating
hole in the plug.
Check the tightness of crank case and change the
sealing if required.
Adjust the carburettor, clean the nozzle.
Correct
spark Incorrectly mixed petrol with oil. Mix correctly the fuel
Lumpy running
Engine
missfires
Irregular
spark Not suitable plug Oiled plug Change the plug The plug is to be screwed out and cleaned
The engine will not fire
or stops
Defects in the fuel
supply
No fuel in the tank.
The fuel tap in the supply piping is closed
or insufficiently opened.
Choked fuel filter above the tap.
The choked piping or strainer in the
carburetor.
The choked hole in the plug hole.
The choked nozzle in carburetor.
Leaky float,
Needle valve does not shut.
Open the fuel tap to reserve.
Open the fuel tap.
The fuel tap be removed & filter cleaned.
Dismantle the piping & carburetor and clean the nozzle
and blow it through.
Clean the de-aerating hole.
Screw out the nozzle and clean it.
Solder or change it.
Change the damaged valve.
Spark at the cable
end
Oiled plug.
Damaged plug insulation.
Short circuit between the plug electrodes.
Big distance of plug electrodes.
Bonding of plug to the frame due to water
or mud.
Change the plug or clean it.
Change the plug.
The electrodes are to be seperated to the distance of
abt. 0.7 mm.
The electrodes are to be brought to the distance of
0.7 mm.
Change and dry the terminal the plug and the cable
The plug does not give the
spark
No spark
at the
cable end
Burnt cable insulation.
Damaged cable shoe.
Faulty Tranzimo unit or transistor only.
The cable is to be wound with insulating tape and
changed as soon as possible, change the terminal.
Change the cable shoe.
Change the Tranzimo unit or transistor only.
The carburettor and fuel supply faultless
The plug
is correct.
Engine
has no
compre-
ssion.
Broken piston ring.
Seized piston ring.
Sealing under the plug is leaky.
Seized piston.
Remove ring from the piston & replace it by new one.
Remove the ring, clean it and put it in again.
Replace the sealing by a new one.
Dismantle and repair.
The engine does not fire or stops
Carburettor is
correct, the
engine has
compression,
the plug gives
the spark.
Overheated engine.
Insufficient lubrication.
Broken gas cable.
Bad sealing between the carburettor and
cylinder.
The engine is to be allowed to cool down and to be
held on lower speed.
Care be taken the oil with petrol is in correct ratio and
throughly mixed through.
Change the cable or repair it.
Change the sealing, tighten the flange.
Too much settled carbon in the cylinder,
head and exhaust silencer.
Partially choked fuel supply.
Wrong adjustment of firing.
Wrongly regulated carburetor.
Seized carburettor mover.
Choked exhaust silencer.
Worn interior of lid and piston.
Dismantle the head, cylinder, and exhaust and remove
the carbon.
Diamantle the piping and clean it.
Adjust the advanced ignition.
Adjust idle run, needle position & clean the air filter.
Loosen the mover and adjust it.
Clean the exhaust silencer.
New re-bore of cylinder, new piston and rings.
Permanently
The engine sucks false air (the box halves
or carburettor flange do not seal).
Damaged sealing ring.
The cylinder head does not seal.
The brake shoes rub against the drums.
Choked air filter.
The box halves are to be seperated , the contact
surfaces be cleaned, the sealing substance be applied
and mount firmly, change the sealing under the
carburetor flange.
Change the sealing ring.
Grind it.
Adjust the brakes.
Clean it.
Engine output is insufficient
Periodically
Partially choked fuel supply or the strainer
in the top of carburettor.
The gas cable seizes.
Faulty plug.
Overheated engine.
Fallen out needle lock in carburettor
The fuel supply or the strainer are to be cleaned.
Oil the cable, respectively change it.
Change the plug.
Let the engine cool down and keep it on low speed.
New lock.
Clutch slips. Dirty clutch jaws. Clean the jaws, check sealing of clutch (sealing rings).
Page 8 Babetta type 28 owners handbook pages 41 to 45 jkw