GAS GAS MC Boy 50 User manual

MANUAL DEL USUARIO
USER MANUAL
MANUEL D’ENTRETIEN
LIBRETTO D’USO
BETRIEBSANLEITUNG

ENGLISH
USER MANUAL
USER MANUAL

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ACKNOWLEDGEMENTS TO THE PURCHASER
GAS GAS thanks you for the trust you have placed in us.
We are delighted that you have selected the MC Boy 50 / EC Boy 50 motorcycle and we would
like to welcome you to the GAS GAS family.
Get to know your new machine well. This bike incorporates our accumulated competition experience
and that which we have gained from the achievement of many important titles.
You now possess a motorcycle with which, as well as feeling comfortable, you are offered the
infinite possibilities of driving at the highest level of your skill while maintaining a maximum of
security.
This manual provides you with a good basic knowledge of the features and machine handling. It
also contains many important instructions regarding safety and provides information about the
basic maintenance and inspection procedures.
Thank you for your trust in us, and welcome to GAS GAS motorbikes.
GAS GAS MOTOS, S.A.

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Important warning
Read this Manual carefully. It contains all the necessary information for your safety, and that of
others, as well as guaranteeing the correct conservation and maintenance of the GAS GAS
motorcycle you have just acquired.
All of the necessary instructions for the correct driving and handling of this vehicle are set out
below. Each message is preceded by a symbol whose meaning is as follows:
Caution! This symbol indicates all of the rules and precautionary measures that must be
taken in order to avoid any physical injury, serious or slight, including death of the user;
to ignore these represents a serious danger.
Warning! This symbol introduces special warnings to avoid damage to your motorcycle.
Should these warnings be ignored, the guarantee may be automatically invalidated.
Miscellaneous notes. These are instructions necessary for optimum use of control and
adjustment operations, as well as conservation and maintenance work on the motorcycle,
so that you may benefit from a maximum of driving satisfaction.
The aim of this Manual is to help the user minimise or avoid possible damage to people,
property, the environment, and naturally to your new motorbike. Therefore, all the information
presented here is based on data obtained from the latest models put on the market just before
publication. However, GAS GAS Motos, S.A. reserves the right to make modifications without any
prior warning to consumers and without incurring any additional obligations in so doing. Your local
dealer will also provide you with any information as might be deemed necessary.

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Index
Acknowledgements to the purchaser 3
Important warning 4
Index 5
Quick Guide to Maintenance 6
Fuel - Petrol/oil mixture 7
Fuel tank 7
Fuel tap 8
Before starting the engine 8
Starting the engine 9
Stopping the engine 9
Riding the motorcycle 10
Stopping the motorcycle 10
Running-in period 11
Transmission oil - Checking the level 11
-Filling 12
-Changing 12
MC Boy 50 cooling system - Checking/filling 13
EC Boy 50 cooling system - Checking 13
Carburettor - Adjusting throttle cable 14
- Adjusting idle speed 14
Spark plugs - Inspecting 15
Air Filter - Cleaning 15
Front brake fluid - Checking 16
Rear brake fluid - Checking 16
Front brake lever - Adjusting 16
Rear wheel - Centre alignment 17
Chain slack - Checking 17
Master link - Checking 17
Tyre pressures - Checking 18
Brake pads - Checking 18
Brake circuit - Bleeding 19
Front fork - Oil level 19
Lubrication 20
Identification 21
Guarantee manual 22

Specifications
EC Boy-50 MC Boy-50
49.38 / 5 49.38 / 12
1 (one)
39 x 41.8 mm
Air Liquid
Electronic with variable advance
Automatic
Single gear
Primary by gears,
Secondary by chain
250 cc of SAE 20 oil
CHASSIS
Deltabox, elliptic profile tubes in CRMo, aluminium rear swingarm
Marzocchi hydraulic fork - 140 mm
Single-shock absorber Sachs - 155 mm stroke
Disk, 160 mm diameter, AJP calliper
Disk, 150 mm diameter, AJP calliper
Duralumin wheels
2.5 - 14" 2.5 - 10"
2.75 / 3.00 - 12 2.75 - 10"
Forged aluminium with retractable toecap
Dell'Orto 19 mm diameter carburettor with
polyurethane sponge filter diffuser
Dell'Orto 14 mm diameter carburettor with
polyurethane sponge filter diffuser
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Description
Displacement / power cc/CV
Type
Number of cylinders
Bore and stroke
Cooling system
Engine lubrication system
Engine supply system
Ignition system
Clutch
Gear changes
Transmission
Transmission lubrication system
Type
Front suspension
Rear suspension
Front brake
Rear brake
Wheels
Tyres
- Front
- Rear
Kick-start pedal
Shift pedal and rear brake
ENGINE
Two-stroke single cylinder, layer admission directly to crankcase
2% mixture ratio
Forged aluminium
Quick guide to maintenance

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Fuel – Petrol/oil mixture
The motorcycle is fitted with a two-stroke internal
combustion engine. This type of engine requires a
mixture of petrol and oil.
To ensure the correct working of the engine, the following are
recommended:
- Use high quality petrol, with an octane rating equal to or
above 90 (RON + MON)/2 or 98 (RON).
- Use 2T synthetic oil.
Warning:
- If the recommended oil is not available, use semi-synthetic oil.
- Do not mix different oil-types.
Mixture ratio: oil, 2% of petrol volume (50 parts petrol to every 1
part oil).
Note: we recommend first preparing the mixture in a suitable
container and then filling the fuel tank.
Fuel tank
This has a rapid access cap (A) and a vent hose (B) to allow
gases produced in the tank to escape.
- To open the cap, lift the clip in the direction shown by the arrow
and turn to the left.
Warning: Regularly check the cap seal and vent hose to ensure
they are leak proof. Risk of spillage.
I
7
1
B
A

Before starting the engine
- Open the fuel tap.
Note:
- If the engine is cold then pull the
choke upwards (A) and, then, rotate it 1/4of
a turn to the left or the right to secure it in place.
Once the engine is turning over regularly at
idle speed, return the choke (A) to the rest
position.
- Do not use the choke on hot days or when
the engine is hot.
In this case, hold the throttle lever partially
open until the engine starts.
C
-8-
Reserve Open Closed
Fuel tap
This has three positions: open,
closed and reserve.
The diagrams below show the
position of tap (A) for each case.
8
C
A
A
2
8
3

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8
8
5
Stopping the engine
-With the throttle grip in rest position
(engine idle), press stop button (A) until
the engine stops.
4
A
A
C
Starting the engine
Kick the start-pedal (A)
in the direction shown
by the arrow until the
engine starts.
Warning: once the engine is
running, fold the kick starter into
the engine.
C

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6
Riding the motorcycle
- To ride the motorcycle simply accelerate, this will activate
the automatic clutch system.
Stopping the motorcycle
- Release the throttle lever.
- Use the front (A) and rear (B) brakes.
Warning: Depending on circumstances and ground surface, it may
be better to use the front or rear brakes independently.
C
7
A
B

Running-in period
Care of the engine during the first hours
of use is vital for obtaining the best from
your motorcycle.
Therefore, we recommend:
- Strictly observe the oil and petrol ratios shown,
and use the recommended 2T oil – see section “Fuel
- petrol/oil mixture”, page 7.
- In the first hour of use, keep the engine at a moderate
turnover speed (never go to maximum turnover).
- Constantly change the speed, by opening and
closing the throttle alternately.
ITransmission oil – Checking the
level
If the motorcycle has been used
recently, wait a few minutes before checking the
level.
Note: the motorcycle should be perpendicular
to the ground.
Warning: Place a suitable recipient under the
engine to collect possible oil spillage.
- Remove the oil level screw (A).
The level is correct if it reaches the lower edge
of the oil level hole (A). If the level is lower then
more oil must be added.
C
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7
A
8
7

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9
8
Transmission oil – Topping up
If necessary, top up with oil:
- Remove the oil filler cap (A).
Warning: Use the recommended oil – See
Quick guide to maintenance, page 6.
- Add oil until it begins to pour out of the hole (B).
Warning: Do not overfill the engine! Risk of
damage to engine.
- Fit and tighten the oil level screw (B).
- Replace filler cap and tighten (A).
C
7
Transmission oil – Changing
- Start the engine and keep it running until
it warms up, then stop the engine. To drain
out the used oil, remove the oil release plug (A)
located underneath the engine.
- Replace the drain plug using a new seal washer.
Tighten to 20 Nm.
- Remove the filler cap (B) and fill with oil (250 cc).
Warning: Use the recommended oil – See Quick
guide to maintenance, page 6.
- Tighten the filler cap.
Warning: Do not pour used oil down the drain.
A
A
B
7
7
B
A
C

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MC Boy - 50 cooling system – Checking/filling
The MC Boy-50 is fitted with a liquid cooling system.
Warning: If the motorcycle has just been used, wait a few
minutes before opening the radiator cap. Risk of burns!
- Rotate the cap (A) anti-clockwise and remove it.
- The level of coolant should be at the lower edge of the filler
neck of the radiator, below the position of the cap seal. If this
is not the case, top up with coolant.
Warning: only use coolant suited to light-alloy engines, with
antifreeze protection of up to -30 ºC.
C
A
10
7
EC Boy-50 cooling system – Checking
EC Boy-50 is fitted with an air cooling system.
The maintenance of this system consists of keeping the
cylinder blades and cylinder head (A) clean of mud and
accumulations that may obstruct the air flow.
C
7
11
A

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12
Carburettor – Adjusting throttle cable
The throttle lever cable should have a
free play of between 2 to 3 mm.
If necessary, adjust as described below:
- Raise the dust guard (A) on the throttle lever cable.
- Turning the threaded terminal (B) to the right
increases the play of the cable, and turning it to the
left reduces the play.
C
7
B
13
A
B
Carburettor – Adjusting the
idle speed
The carburettor has an idle
adjusting screw (A), which acts on the
opening of the carburettor throttle curtain,
and an air adjusting screw for the low
system (B), which controls the air/fuel
mixture.
7
C
A

14 Spark plugs – Inspecting
The electrode separation is from
0.6 to 0.7 mm.
C
7
Air Filter – Cleaning
A clean air filter not only improves engine
performance but also prolongs its useful life. It
should therefore be cleaned regularly.
To reach the air filter, proceed as follows:
- Remove the bolt indicated by the arrow, remove the seat
by pulling it backwards to dislodge it from its forward
attachment.
- Using a screwdriver or similar, remove the elastic band
(A) from the bolt holding it.
- Remove cover (B) from the filter box.
- Remove filter.
- Wash the filter in warm water and soap and, once dry,
grease with special filter oil.
- Refit the elements in reverse order, noting that the seat
must be pressed downwards and forwards to insert it into
its forward attachment, in the front part of the padding.
C14
AB
7
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0.6 ~0.7 mm
_

16
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15
Front brake fluid –Checking
The level is correct if it falls within
the upper half of the transparent
window (A). If not, top up with a recommended
brake fluid.
C
7
Rear brake fluid –
Checking
The level is correct
if it falls within the upper half
of the transparent window (A).
If not, top up with a
recommended brake fluid.
C
Front brake lever –
Adjusting
The front brake lever should
have a maximum play of 3 mm.
To adjust, proceed as follows:
- Adjust the maximum turn of the lever
using bolt (A), to suit the driver.
- Adjust the play of the lever using bolt
(B).
C
7
7
3 mm max.
17
A
A
B
A

20
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19
Rear wheel – Centre alignment
The rear axle has easily
graduated eccentrics for this
operation.
To ensure perfect wheel alignment, make
sure that the marks of both eccentrics are in
the same position on both sides.
CChain slack –Checking
Adjust chain tension with the
eccentrics so that the slack in the
tensed zone is 1.5 cm.
C
18
7
7
Master link –Checking
The master link of the chain has an elastic
locking clip.
As shown in the photo, place the closed part of the
clip in the direction of the chain rotation.
C
7
1.5 cm

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21
22
Tyre pressures –Checking
Check tyre pressures regularly in
order to obtain the best road
holding possible.
INFLATION PRESSURES:
EC BOY-50
Front wheel: 0.8 BAR / 11.5 PSI
Rear wheel: 0.8 BAR / 11.5 PSI
MC BOY-50
Front wheel: 0.9 BAR / 13 PSI
Rear wheel: 0.8 BAR / 11.5 PSI
C
Brake pads –Checking
The brake pads, both front and rear,
should be checked for wear
periodically, in order to enable you to brake
effectively in any situation.
Replace if the thickness of the friction material
of the pads reaches 1 mm.
C
7
7