N-Zeta 501/01 Instruction manual

orkshop
anual
This manual covers all Cezeta and N-Zeta models
M
W

- 1 -
INTRODUCTION.....................................................................................................- 4 -
CARBURETTOR CLEANING AND MAINTENANCE .............................................- 5 -
Jikov 2924 M 13 carburettor........................................................................................................................- 6 -
To Dismantle The Float Chamber:.........................................................................................................- 6 -
To Set The Carburettor According To The Manufacturers Specifications:.................................- 7 -
Jikov 2924 S 11 Carburettor for the 501/03 to /05 models;..................................................................- 9 -
Jikov 2924 S 13 Carburettor for the 502/00 to /01 model.....................................................................- 9 -
To Dismantle The Choke Device:...........................................................................................................- 9 -
To Set The Carburettor According To The Manufacturers Specifications:...............................- 10 -
Induction Silencer Maintenance and Cleaning.....................................................................................- 12 -
For the 501/01 –03 –05 models...........................................................................................................- 12 -
E N G I N E ...........................................................................................................- 13 -
Cylinder Head and Cylinder Barrel Removal. .......................................................................................- 13 -
Piston..............................................................................................................................................................- 14 -
Piston Grading According To Diameter D2 –Model 502....................................................................- 15 -
Piston Grading According To Diameter D2 –Model 501....................................................................- 15 -
Cylinder ..........................................................................................................................................................- 16 -
Assembly Table For Models 501/01, 03, 05...........................................................................................- 16 -
Assembly Table For Models 502/00, 01..................................................................................................- 16 -
Gudgeon Pin Bush For Models 501/01, 03, 05......................................................................................- 17 -
For Models 502/01, 00.................................................................................................................................- 17 -
Fitting The Piston.........................................................................................................................................- 17 -
Fitting The Cylinder Barrel And Cylinder Head....................................................................................- 18 -
Cooling Fan...................................................................................................................................................- 18 -
Setting The Ignition Advance....................................................................................................................- 21 -
Removal Of The Dynastarter.....................................................................................................................- 21 -
To Dismantle The Clutch Operating Bracket........................................................................................- 22 -
Removal Of The Gearbox Sprocket.........................................................................................................- 23 -
To Dismantle The Clutch And Primary Drive........................................................................................- 23 -
To Remove The Kick Starter Quadrant. .................................................................................................- 25 -
To Dismantle The Gear Change Shaft ....................................................................................................- 25 -
To Replace The Crankshaft and Gearbox Output Shaft Seals .........................................................- 26 -
To Remove The Engine From The Frame..............................................................................................- 26 -

- 2 -
To Dismantle The Gearbox And Crankshaft Mechanism...................................................................- 27 -
Dismantling The Crankshaft Assembly..................................................................................................- 28 -
Connecting Rod For The 501 Model –356-12-230 ...........................................................................- 31 -
502 Model –450-12-230 ..............................................................................................................................- 31 -
Assembling The Engine .............................................................................................................................- 32 -
C Y C L E P A R T ...............................................................................................- 36 -
Model 501 Removal Of The Rear Sprocket............................................................................................- 36 -
Model 502 - Removal Of The Rear Sprocket .........................................................................................- 36 -
Model 501 - Removing The Rear Drive Chain.......................................................................................- 36 -
Model 502 - Removing The Rear Drive Chain.......................................................................................- 37 -
Chain Maintenance......................................................................................................................................- 37 -
Front Fork Removal.....................................................................................................................................- 38 -
Model 501-Removal Of The Suspension Damper................................................................................- 39 -
Model 502 –Dismantling The Rear And Front Suspension Units ...................................................- 39 -
Chain Case Removal...................................................................................................................................- 39 -
To Dismantle The Pivoted Rear Arm.......................................................................................................- 40 -
Model 502 –Dismantling The Pivoted Rear Fork.................................................................................- 40 -
Dismantling The Headlamp .......................................................................................................................- 41 -
To Dismantle The Fuel Tank .....................................................................................................................- 41 -
Luggage Compartment Removal.............................................................................................................- 41 -
Removing The Bodywork And Its Accessories....................................................................................- 41 -
To Dismantle The Choke Device..............................................................................................................- 42 -
Dismantling The Fuel Tap Control...........................................................................................................- 42 -
To Dismantle The Gear Change Pedal....................................................................................................- 42 -
E L E C T R I C A L E Q U I P M E N T ...............................................................- 44 -
Dynamo...........................................................................................................................................................- 44 -
PAL Voltage Regulator 6 V .......................................................................................................................- 45 -
PAL Dynastarter ...........................................................................................................................................- 46 -
PAL 12V Regulator With Contactor.........................................................................................................- 46 -
Operation Of The Dynastart With The Regulator And Contactor ....................................................- 47 -

- 3 -
PAL 02-9421.04 Regulator With Contactor –Technical Data And Setting.....................................- 48 -
Regulator With Contactor - Mechanical Checking ..........................................................................- 49 -
Operation Checking.................................................................................................................................- 49 -
PAL 02-9490.60 Dynastart –Technical Data..........................................................................................- 50 -
Dynastart –Mechanical Checking .......................................................................................................- 50 -
Operation Checking.................................................................................................................................- 50 -
Lights..............................................................................................................................................................- 51 -
Electric Horn..................................................................................................................................................- 51 -
Leads...............................................................................................................................................................- 51 -

- 4 -
N Z E T A S c o o t e r R e p a i rM a n u a l
Introduction
This book represents the Repair Manual for owners of NZETA scooters made by the
world famous CZ Motorcycle Works in Strakonice Czechoslovakia then assembled
and finished by Jawa New Zealand. The reliability of this machine is well known to be
exceptional, its owner having nothing more to do than normal servicing according to
the Owner Handbook supplied with every machine. This Manual is intended for
Service Repair Shops and for those of the NZETA owners who prefer to carry out
repairs on their machines after many years of service. That is why the necessary
information for the repairs of the crankshaft and connecting rod mechanism and
electrical equipment is provided. Because the maintenance and repairs of the cycle
part are, due to the NZETA scooter monocoque bodywork, restricted to the minimum
and are well described in the Owner Handbook, only the most essential matters shall
be discussed here. It is necessary to warn NZETA scooter owners that, they should
consider their mechanical abilities carefully and to only undertake jobs which they are
able to complete successfully. It may be preferable a seek help in service
workshops. When describing individual repair jobs reference will be made to the
special tools supplied by the manufacturers, nevertheless the design of the NZETA
scooter makes it possible for most jobs to be done with normal tools or, where
necessary, a with universal pullers found in the equipment of every service repair
shop

- 5 -
Carburettor Cleaning and Maintenance
On most occasions, carburettor faults are due to impurities entering with the
petrol or air. The time for regular carburettor cleaning will depend on the manner in
which the machine is used. It is not recommended to carry out any carburettor
repairs apart from washing it in clean petrol and setting according to the maker’s
instructions. Any departure from the basic carburettor setting may be carried out with
a view to the condition of the scooter, its use in varying climatic conditions, or the fuel
used. In these cases, keep within narrow limits keeping a careful check of the fuel
consumption and performance after the differing setting has been carried out.
Other carburettor defects which may occur in operation should be remedied
by repairing or, replacing of its parts. This applies to the throttle valve which, in case
of excessive play in the mixing chamber, should be replaced with a new one or in the
case of seizure should be repaired using fine emery cloth or sharpening stone. One
should never omit, to wash the throttle valve in petrol after it has been repaired, to
remove the fine emery which might cause wear of the mixing chamber.
Another carburettor trouble is its constant flooding. This may be due to a leaky
float or lack of tightness of the float needle / dirt under the needle. To repair the float,
it has to be soldered after drying out or replaced. Lack of tightness of the float needle
in its seat in the float chamber top will be removed by grinding using lapping paste or
by replacing the parts. In case of damage to the throttle valve needle the needle has
to be replaced.

- 6 -
All these jobs are done without removing the carburettor from the crankcase,
the carburettor being accessible after opening the side door. The main jet is also
accessible through the side door. To clean it, fine horse hair should be employed
and not a piece of wire or any other hard object. Removal of the jet will be described
for each carburettor separately. To clean the carburettor, it is necessary to first
remove it from the crankcase through the side door.
Jikov 2924 M 13 carburettor Fig.1
This model has been employed in the 501/01 and 501/03 scooter models. It is a
monoblock type carburettor. The main jet #19 is located in the float chamber. It is
accessible after removal of the float chamber top #20
To Dismantle The Float Chamber, Proceed As Follows:
Close the fuel tap first and remove the fuel supply pipe. After unscrewing the
four screws #32, remove the float chamber top together with the gasket #21 and float
#31. To assemble, proceed in the reverse manner.
The throttle valve needle #7 is located in the middle of the throttle valve #4
and is accessible after its removal from the mixing chamber after unscrewing the
mixing chamber top #8. After compressing the spring #5, free the control cable from
the throttle valve notches #4 and thereby the spring resting against the needle circlip
#6 and throttle valve. The circlip #6 secures the correct position of the needle #7. To
assemble, proceed in the reverse manner.

- 7 -
The idling jet #17, the pilot, air screw #18 and the throttle valve stop screw
#15 are located on the R. H. side of the carburettor and are accessible through the
bodywork side door. When repairing the float, push out the float spindle #31a first
thus freeing the float #31. Repair the float or replace it and assemble proceeding in
reverse manner. The float spindle is secured against working free by two screws #32
which fasten the float chamber top #20. In case of loss of any of these four screws, it
is necessary that the float chamber top should be always fastened with two screws
on the sides of the spindle. Dismantling or assembling the float chamber top with
float it is always necessary to handle carefully these parts in order not to damage
the, float stop which would alter the fuel level.
To Set The Carburettor According To The Manufacturers Specifications,
Proceed As Follows:
First check the throttle valve needle position / how to assemble the throttle
valve has been described in the preceding paragraph / slacken the lock nut #10,
screw the cable guide #9 into the mixing chamber top #8 thus freeing the throttle
valve #4. After removing the float chamber top, unscrew the main jet #19 and check
its value.
The pilot air screw #18 serves to set the idling speed. Tighten the pilot air
screw first /clockwise/ and then slacken it /anticlockwise/ by the value prescribed for
setting. With the engine running, its idle speed is set by means of the throttle valve
stop screw #15. By unscrewing the cable guide, the throttle cable slack can be taken
up and the cable guide is then secured with the lock nut #10.

- 8 -
The carburettor is set in the Works for running in, and it has to be reset after the first
2000 km / 1200miles to the following values:
Main Jet 100 to 102 to Solex
Idling Jet 55 to Solex
Needle position 3rd notch from the top
Pilot air screw slacken by ¾ of a turn from tight /anticlockwise/
Fig. 1

- 9 -
Jikov 2924 S 11 Carburettor for the 501/03 to /05 models;
Jikov 2924 S 13 Carburettor for the 502/00 to /01 model Fig.2
These are monoblock type carburettors. They are also equipped with a choke device
for making the mixture rich to assist in starting the engine when cold. The main jet
#24 is located in the jet carrier #23 and is accessible after being unscrewed. The
throttle valve needle #4 is eccentrically located in the throttle valve #3 and is
accessible after the removal of the valve from the mixing chamber when the mixing
chamber top #7 has been first removed.
After compressing the spring #6, free the control cable from the throttle valve
#3 notch and thereby the spring resting against the needle circlip #5 and the throttle
valve. The circlip #5 secures the correct position of the needle #4. To assemble,
proceed in the reverse manner. The idling jet #26, the pilot air screw #27 and the
throttle stop screw #29 are located on the RH side of the carburettor and are
accessible through the bodywork side door.
To Dismantle The Choke Device, Proceed As Follows:
Having unscrewed the choke screw #16, remove the slide #13 suspended on
the cable. Unscrewing the cable screw #14 and the slide #13, will free the cable. To
assemble, proceed in the reverse manner.

- 10 -
To Set The Carburettor According To The Manufacturers Specifications,
Proceed As Follows:
First check the throttle valve #4 needle position. Slacken the lock nut #8;
screw the cable guide #9 into the mixing chamber top #7 thus freeing the throttle
valve #3. After unscrewing the jet carrier #23, check the correct value of the jet. To
set the idling speed, use the pilot air screw #27. First tighten the pilot air screw
/clockwise/ and then slacken it /anticlockwise/ to the prescribed setting value.
With the engine running, its idling speed is set by means of the throttle valve
stop screw #29. To take up the throttle cable play, unscrew the cable guide #9 and
secure the guide with the lock nut# 8.
The carburettor is set in the Works for running in, and it has to be reset after the first
2000 km / 1200miles to the following values:
2429 S 11 Carburettor on the 501/03 to 05 models
Main Jet 105 to Solex
Idling Jet 55 to Solex
Needle position 2nd notch from the top
Pilot air screw slacken by ¾ of a turn from tight /anticlockwise/
2429 S 13 Carburettor on the 502/00 to 01 models
Main Jet 109 to Solex
Idling Jet 40 to Solex
Needle position 2nd notch from the top
Pilot air screw slacken by ½ to 1 turn from tight /anticlockwise/
When refitting the carburettor to the engine, do not omit the carburettor base gasket
taking care not to damage it. Tighten the carburettor uniformly to the crankcase.

- 11 -
Fig. 2

- 12 -
Induction Silencer Maintenance and Cleaning
For the 501/01 –03 –05 models fig. 3
The silencer serves to reduce the engine noise level and replaces the normal
air cleaner at the carburettor. For its correct operation, it must be maintained as
follows:
After about 3000 –5000 km / 2000 –3000 miles, rotate and remove the silencer top
#1, and then remove the silencer element #3. The element must be thoroughly
washed in clean petrol. Moisten the clean element with a mixture of oil and petrol to
the ratio of 1:1 and leave it to drip. After replacing the element, the silencer top is
secured against working free by rotating the top to engage the fitting clips to the
silencer body #22. Care should be taken to ensure that the rubber sleeve #4
connecting the induction silencer to the carburettor does not become distorted or
damage to prevent dirt entering the engine. The drain hole in the sleeve must always
face downwards.
A loose silencer top will manifest as a roaring noise when the engine is
running. In such a case, the element may fall out resulting in dirt entering the engine
as well as the mixture becoming lean and the engine loosing power at high r.p.m.
and overheating. On the other hand, with the element excessively dirty, the mixture
will become too rich resulting in increased fuel consumption and the engine running
lumpy / four-stroking.
The induction silencer is fitted to the bodywork with 2 bolts #26 which are
accessible after the removal of the silencer top and the element. The Induction
silencer is accessible after removal of the under seat luggage compartment and seat
/ this job will be described in a following chapter dealing with the bodywork/.
Fig. 3

- 13 -
E n g i n e
The following jobs can be carried out without removing the engine from the
bodywork:
Removal of the cylinder barrel and head for replacement, re-boring or
decoking, cleaning or replacement of the piston, replacement of the connecting rod
small end bush, ignition advance setting, removal of the ignition and dynamo,
replacement of the gearbox chain sprocket, the primary drive chain and final drive
chain, replacement and adjusting of the clutch and gear change mechanism, removal
of the cooling fan.
Cylinder Head and Cylinder Barrel Removal.
First remove the luggage compartment –this job is described in the Bodywork
chapter. Dismantle the cooling fan - this job is described in the next chapter. For the
501 model, unscrew the two exhaust pipe nuts, for the 502 model, unscrew the bolt
fastening the exhaust pipe and remove the pipes from the cylinder barrel.
With the 14mm box spanner, unscrew the four nuts fastening the cylinder
head and remove the head through the top opening in the bodywork. Fig.4
Fig. 4
Fig. 5

- 14 -
To dismantle the cylinder barrel, it is necessary to first unscrew the studs
fastening the cylinder barrel to the crankcase. Thread two nuts onto the studs and
tighten them onto each other. Now unscrew them together with the stud by turning
the bottom nut. In this manner, remove all four studs. fig.5
To free the cylinder barrel, carefully lever it using screwdrivers after having
first brought the piston to BDC with the kick-starter pedal. Having removed the
cylinder barrel, cover the hole in the crankcase under the piston with a clean cloth; it
is now possible to proceed to decoke, to take off the piston or to replace the small
end bush. Using the S-3 special pliers or 3 tin foils, remove the piston rings. The
piston should be removed only when it is to be replaced or when the gudgeon pin or
small end bush have to be replaced. For the original piston with the pressed in
gudgeon pin / scooters 501/01 –03 up to engine Nº. 132252/ puller S-38 should be
used for extracting the gudgeon pin. For the new piston with floating pin / model
501/05 and 502/00 –01/ use the locating pins S-3 and push out the gudgeon pin
with light pressure by hand. When dismantling the piston, first remove the two circlips
securing the gudgeon pin. Never drive out the gudgeon pin as there is danger of
bending the connecting rod.
Piston
For scooter model 501/01, 03 and 05, new piston Part Nº. 356-12-241 should
be employed only. Together with this piston, setting of the 2924 M 13 carburettor has
to be modified as indicated. Pistons are marked on the top with letters according to
the manufacturers dimensions determining their assemble with cylinder barrels and
gudgeon pins. The marking consists of two letters, the first of which A, B, C
determines the piston diameter and thereby its suitability for the corresponding
cylinder barrel marking. The second letter Y, Z marks the dimensions of the gudgeon
pin diameter.

- 15 -
Piston Grading According To Diameter D2 –Model 502 Fig.6
A –0.01 B –0.01 C –0.01 Nº.
Standard 57.860 57.870 57.880 450-12-026
1st rebore 58.110 58.120 58.130 450-12-027
2nd rebore 58.360 58.370 58.380 450-12-028
3rd rebore 58.610 58.620 58.630 450-12-029
4th Rebore 58.860 58.870 58.880 450-12-030
Piston Grading According To Diameter D2 –Model 501 Fig.6
A –0.01 B –0.01 C –0.01 Nº.
Standard 57.875 57.885 57.895 356-12-241
1st rebore 58.125 58.135 58.145 356-12-242
2nd rebore 58.375 58.385 58.395 356-12-243
3rd rebore 58.625 58.635 58.645 356-12-244
4th Rebore 58.875 58.885 58.895 356-12-245
Fig. 6

- 16 -
Cylinder
For model 501 scooters, only cylinders with increased bore by 0.01mm as compared
to the motorcycle engines have to be employed. Cylinder bores for the individual
gradings are indicated in this table; the cylinder barrels are marked on the top flange
beside the letter A, B, C determining the corresponding pistons with the letter “S”.
Fig. 7 shows the cylinder barrel, piston and gudgeon pin.
Assembly Table For Models 501/01, 03, 05
A-S B-S C-S Nº.
Standard? 58.01 + 0.01 58.02 + 0.01 58.03 + 0.01 356-12-241
1st rebore 58.26 + 0.01 58.27 + 0.01 58.28 + 0.01 356-12-242
2nd rebore 58.51 + 0.01 58.52 + 0.01 58.53 + 0.01 356-12-243
3rd rebore 58.76 + 0.01 58.77 + 0.01 58.78 + 0.01 356-12-244
4th rebore 59.01 + 0.01 59.02 + 0.01 59.03 + 0.01 356-12-245
Assembly Table For Models 502/00, 01
A B C N º.
Standard? 58.01 + 0.01 58.02 + 0.01 58.03 + 0.01 502-12-020
1st rebore 58.26 + 0.01 58.27 + 0.01 58.28 + 0.01 502-12-021
2nd rebore 58.51 + 0.01 58.52 + 0.01 58.53 + 0.01 502-12-022
3rd rebore 58.76 + 0.01 58.77 + 0.01 58.78 + 0.01 502-12-023
4th rebore 59.01 + 0.01 59.02 + 0.01 59.03 + 0.01 502-12-024
The cylinder barrel for model 502 scooters are marked on the top flange only with
letters indicating grading A, B, C.

- 17 -
Gudgeon Pin Bush For Models 501/01, 03, 05
Gudgeon pin bush diameter is 15.025 0.01mm for standard gudgeon pin grading
= dia. 15.000 –0.0025mm, grading = dia. 14.9975 –0.0025mm and 15.125 –
0.01mm for oversize gudgeon pin dia. 15.1 –0.004mm.
For Models 502/01, 00
Gudgeon pin bush diameter is 18.25 0.01mm for standard gudgeon pin grading
= dia. 18.000 –0.0025mm, grading = dia. 17.9975 –0.0025mm and 18.125 +
0.01mm for oversize gudgeon pin dia. 18.1 –0.004mm.
After every replacement of the bush this has to be reamed to the prescribed
diameter after pressing into the connecting rod small end. If the reaming is done
without removing the engine from the bodywork, it is necessary to cover the
crankcase very well to prevent bronze chips from entering the engine. Before fitting
the bush, it is advisable to heat the connecting rod small end to about 80 ºC / 176 ºF
using a blowtorch or similar. This causes the hole into which the bush is to be fitted
to become slightly expanded and the bush will be more easily pressed in. To fit and
remove the gudgeon pin and bush employ puller S-34,
Fitting The Piston
First slip the gudgeon pin into the piston from one side, position the piston over the
connecting rod and use guide pin S-13 to push the gudgeon pin through the
connecting rod small end and into the other side of the piston. Locate the pin
between the circlip grooves and then insert the clips into their grooves. Only then
should the piston rings be fitted into their appropriate grooves.

- 18 -
Fitting The Cylinder Barrel And Cylinder Head
Clean the Crankcase seating face and preferably a new gasket under the
Cylinder Barrel. Provide the Cylinder Barrel with a coating of clean oil inside, move
the piston to TDC by means of the kick starter pedal and then fit the barrel. When
fitting the cylinder barrel, take care to have the piston rings correctly placed with their
ends to the peg in the piston groove.
With the piston and rings sliding in the cylinder barrel, slip the barrel onto the
crankcase taking care not to damage the gasket and then screw the studs into the
crankcase in the reverse manner to their removal. Place preferably a new gasket
under the cylinder head and do not omit to fit the washer under each cylinder head
nut. It is easy to locate them by sliding them down a screwdriver or suitable sized
piece of rod. Tighten the cylinder head nuts sequentially.
Cooling Fan Fig.7
The method of removal with the engine in the bodywork is the same for both
models of scooter. After removing the Vee-belt #14 from the pulley, unscrew the two
nuts #16 from the connecting bolts #15 in the L.H. engine side cover. Remove the
bolts and take the fan assembly #2 off the engine and out through the bodywork side
door. Fig. 8

- 19 -
Fig. 7