Derbi 50cc/6-Speed Service & Repair Manual
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Nacional Motor, S.A., manufacturer of DERBI mopeds and
scooters issues this manual with the object of documenting and
simplifying to the utmost the task of stripping and assembling the
DERBI 50 cc 6 speed engine.
The intended purpose is to provide the maximum support to
mechanics in the practice of their profession in the agencies and
sub-agencies of our marque.
In the lights of our policy of constant improvement, DERBI-
NACIONAL MOTOR, S.A. reserves the right to introduce such
modifications as it deems appropriate without prior notice.
All the information included in this manual is based on the most
recent data available at the time of publication. The drawings and
photographs are intended to serve solely as reference material,
and therefore may not be exactly the same as the components and
parts in the model currently on sale.
NACIONAL MOTOR, S.A.
N.º 7077TH02002
Workshop Manual
Manual de Taller
50 c.c.ENGINE
6 SPEED
INDEX
- General Information ..........................................................................1
- Maintenance .....................................................................................1
- Suspensions ....................................................................................1
- Carburetor .........................................................................................1
- Reed Valve........................................................................................1
- Cooling System.................................................................................1
- Oil pump............................................................................................1
- Extraction and installation of motor ..................................................1
- Cylinder Head ..................................................................................1
- Cylinder - piston ................................................................................1
- Clutch ................................................................................................1
- Crankshaft and gearbox....................................................................1
- Battery...............................................................................................1
- Starter motor .....................................................................................1
- Oil and fuel level pilot ........................................................................1
- Magneto ............................................................................................1
- Electrical Wiring ..............................................................................17
1-1
1. SERVICING RULES
- Use original DERBI spare parts or the parts and lubricants recommended by DERBI.
Parts which do not comply with the DERBI design characteristics may cause damage
to the scooter.
- In cases where specified, use the special tools designed for this model.
- On reassembly always use new gaskets.
- When tightening up a series of screws of nuts, start first with the larger diameter
screws or start with those on the inside or centre of the part, and apply the full torque
specified in two or three diagonal passes.
- Before stripping any parts of the engine, clean it thoroughly to prevent dirt getting into
the inside of the engine.
- Before assembly lubricate all rubbing surfaces.
- After assembly and before running the engine, ensure that all parts have been correctly
fitted and function properly.
1-2
VEHICLE IDENTIFICATION
This manual includes information
which will be useful in servicing, main-
tenance and repair operations on the
families of models: RACER, XTREME,
DRD, and GPR.
SENDA R DRD
GPR Rácing Réplica
• The frame number is located on the
right hand side of the steering tube.
• The engine number is located on
the left hand side of the engine,
(beside the oil filler cap - gear-chan-
ge - clutch).
DIMENSIONS
OVERALL LENGTH (mm.) ...............................2,050
OVERALL WIDTH (mm.) .....................................695
OVERALL HEIGHT (mm.) ................................1,300
WHEELBASE (mm.) .........................................1,345
FRAME R SM
FRAME TYPE ......................................................................................Multi-tube
FRONT SUSPENSION: TYPE ...........................................Showa inverted hydraulic forks
FRONT SUSPENSION: STROKE/ BAR DIAMETER ...................175 mm. / 32 mm.
OIL CAPACITY PER FRONT FORK BAR ..................................175 cc SAE 7.5 W
REAR SUSPENSION: TYPE / STROKE .....................Single in-line shock-absorber / 180 mm.
FRONT TYRE: SIZE .......................................................80/90x21” ..................100/80x17”
FRONT TYRE: PRESSURE ............................................1.0 to 1.1 ....................1.7 to 1.8
REAR TYRE: SIZE .........................................................110/80x18” .................130/80x17”
REAR TYRE: PRESSURE ...............................................1.2 to 1.3 ....................2.0 to 2.1
FRONT BRAKE: TYPE / SIZE ..................................................Hydraulic disc 220 mm.
REAR BRAKE: TYPE / SIZE ....................................................Hydraulic disc 180 mm.
TOTAL CAPACITY FUEL TANK ...........................................................5.5 litres
TOTAL CAPACITY OIL RESERVOIR ....................................................1.0 litre
COOLING LIQUID CAPACITY ..............................................................1.1 litre
ENGINE
OPERATING CYCLE .........................................................................Two stroke
BORE x STROKE............................................................................39.86 x 40 mm.
NUMBER OF CYLINDERS ......................................................................One
TOTAL CUBIC CAPACITY ....................................................................49.9 cc
MAXIMUM POWER.....................................................................8.5 CV at 9,000 rpm
COMPRESSION RATIO ..........................................................................13:1
FUEL ......................................................................................Unleaded petrol 95 octane
ADMISSION SYSTEM .......................................................................Reed valve
STARTER SYSTEM ...........................................................................Kick starter
LUBRICATING SYSTEM ......................................................................Oil pump
COOLING SYSTEM .................................................Liquid-cooled with pump, radiator, and thermostat
CARBURETTOR
BRAND / TYPE ............................................................................Dell´Orto / PHVA 14
ENGINE IDLE SPEED .......................................................................1,900 ± 100
TURNS IDLE JET AIR SCREW .................................................................3
DIFFUSER DIAMETER ........................................................................14 mm.
# IDLE JET .............................................................................................#36
# MAIN JET ..............................................................................................#73
CONICAL NEEDLE: TYPE / STD ADJUSTMENT .................................A8/3rd
SLIDE VALVE ...........................................................................................#30
# EMULSIFIER TUBE ...........................................................................#211GA
CHOKE TYPE ..................................................................................MECHANICAL
# CHOKE JET ..........................................................................................#45
FLOAT ....................................................................................................3.5 gr.
1-3
GENERAL TECHNICAL SPECIFICATIONS
RACER MODELS
1-4
TRANSMISSION R SM
PRIMARY DRIVE................................................................................Spur gears
PRIMARY DRIVE RATIO ....................................................................3.5 (77/22)
CLUTCH ........................................................................................Multi-disc oil bath
GEAR BOX ......................................................................................Constant mesh
GEAR RATIOS:
1st: ..........................................3.09 (34/11)
2nd: .........................................2.00 (30/15)
3rd: ..........................................1.50 (27/18)
4th: ..........................................1.20 (24/20)
5th: ..........................................1.04 (23/22)
6th: ..........................................0.95 (22/23)
TRANSMISSION OIL CAPACITY / TYPE ........................650 cc / AGIP GEAR SAE 10W40
FINAL DRIVE ..................................................................................Chain and gear
FINAL DRIVE RATIO......................................................4.41 (53/12) .................4.07 (53/13)
ELECTRICAL SYSTEM
GENERATOR .........................................................................MAGNETO ALTERNATOR
VOLTAGE / GENERATOR POWER ....................................................12V / 65W
IGNITION TYPE .......................................................................................CDI
IGNITION ADVANCE ...................................................................1.2 mm before TDC
SPARK PLUG.....................................................................NGK B10ES / CHAMPION N1C
SPARK PLUG ELECTRODE GAP ........................................................0.6 mm.
BATTERY ...........................................................................................12 V / 4 A/h
MAIN FUSE .............................................................................................4 A
GENERAL TECHNICAL SPECIFICATIONS
RACER MODELS
DIMENSIONS
OVERALL LENGTH (mm.) .............2,035
OVERALL WIDTH (mm.) ................800 ( R ) / 760 ( SM )
OVERALL HEIGHT (mm.) ..............1,220
WHEEL BASE (mm.) ......................1,355
FRAME R SM
FRAME TYPE ......................................................................................Perimeter
FRONT SUSPENSION: TYPE ........................................PAIOLI conventional hydraulic forks
FRONT SUSPENSION: STROKE / BAR DIAMETER ...190 mm. / 36 mm.........170 mm. / 36 mm.
FRONT SUSPENSION: FORK BAR OIL CAPACITY ....285 cc SAE 10W ........270 cc SAE 10W
REAR SUSPENSION: TYPE / STROKE .....................Single in-line shock absorber / 180 mm.
STEERING ANGLE ...............................................................26º ..............................24.7º
FRONT TYRE: SIZE ........................................................80/90x21” ...................100/80x17”
FRONT TYRE PRESSURE ..............................................1.0 to 1.1......................1.7 to 1.8
REAR TYRE: SIZE .........................................................110/80x18” ...................130/80x17”
REAR TYRE PRESSURE ................................................1.2 to 1.3......................2.0 to 2.1
FRONT BRAKE: TYPE / SIZE .................................Hydraulic Disc 240 mm. .....Hydraulic Disc 260 mm.
REAR BRAKE: TYPE / SIZE ....................................................Hydraulic Disc 180 mm.
TOTAL CAPACITY, FUEL TANK ...........................................................7.0 litres
TOTAL CAPACITY, OIL RESERVOIR ...................................................1.0 litre
COOLING LIQUID CAPACITY .............................................................0.85 litre
ENGINE
OPERATING CYCLE ..........................................................................Two Stroke
BORE x STROKE............................................................................39.86 x 40 mm.
NUMBER OF CYLINDERS ......................................................................One
TOTAL CUBIC CAPACITY ....................................................................49.9 cc
MAXIMUM POWER.....................................................................8.5 CV at 9,000 rpm
FUEL ......................................................................................Unleaded petrol 95 Octane
COMPRESSION RATIO ..........................................................................13:1
ADMISSION SYSTEM .......................................................................Reed valve
STARTER SYSTEM ...........................................................................Kick starter
LUBRICATION SYSTEM ......................................................................Oil pump
COOLING SYSTEM ...................................................Liquid with pump, radiator, and thermostat
CARBURETTOR
BRAND / TYPE ............................................................................Dell-Orto / PHVA 14
ENGINE IDLE SPEED .......................................................................1,900 ± 100
TURNS IDLE JET AIR SCREW ...............................................................23/4
DIFFUSER DIAMETER ........................................................................14 mm.
# IDLE JET ..............................................................................................#32
# MAIN JET .............................................................................................#71
CONICAL NEEDLE: TYPE / STD. ADJUSTMENT ...............................A11/4th
SLIDE VALVE ...........................................................................................#30
# EMULSIFIER TUBE ...........................................................................#211GA
CHOKE TYPE ..................................................................................MECHANICAL
# CHOKE JET...........................................................................................#45
FLOAT ....................................................................................................3.5 gr.
1-5
GENERAL TECHNICAL SPECIFICATIONS
XTREME MODELS
1-6
TRANSMISSION R SM
PRIMARY DRIVE................................................................................Spur gears
PRIMARY DRIVE RATIO ....................................................................3.5 (77/22)
CLUTCH ........................................................................................Multi-disc oil bath
GEARBOX .......................................................................................Constant mesh
GEAR RATIOS:
1st: ...........................................3.09 (34/11)
2nd: .........................................2.00 (30/15)
3rd: ..........................................1.50 (27/18)
4th: ..........................................1.20 (24/20)
5th: ..........................................1.04 (23/22)
6th: ..........................................0.95 (22/23)
TRANSMISSION OIL CAPACITY / TYPE .......................650 cc / AGIP GEAR SAE 10W40
FINAL DRIVE .................................................................................Chain and gear
FINAL DRIVE RATIO......................................................4.07 (53/13) .................3.78 (53/14)
ELECTRICAL SYSTEM
GENERATOR .........................................................................MAGNETO ALTERNATOR
GENERATOR VOLTAGE / POWER ..................................................12 V / 65 W
IGNITION TYPE .......................................................................................CDI
IGNITION ADVANCE ..................................................................1.2 mm. before TDC
SPARK PLUG.....................................................................NGK B10ES / CHAMPION N1C
SPARK PLUG ELECTRODE GAP ........................................................0.6 mm.
BATTERY............................................................................................12 V / 4 Ah
MAIN FUSE ..............................................................................................4 A
GENERAL TECHNICAL SPECIFICATIONS
XTREME MODELS
1-7
DIMENSIONS
OVERALL LENGTH (mm.) .............2,035
OVERALL WIDTH (mm.) ................800 ( R ) / 760 ( SM )
OVERALL HEIGHT(mm.) ...............1,220
WHEELBASE (mm.) .......................1,355
FRAME R SM
FRAME TYPE ......................................................................................Multi-tube
FRONT SUSPENSION: TYPE .....................................Marzocchi Conventional hydraulic forks
FRONT SUSPENSION: STROKE / BAR DIAMETER ...........................195 mm. / 41 mm.
FRONT SUSPENSION: FORK BAR OIL CAPACITY........445 CC SAE 10W.......445 CC SAE 10W
REAR SUSPENSION: TYPE / STROKE .................Single shock absorber progressive /180 mm.
STEERING ANGLE ...............................................................26º ..............................24,7º
FRONT TYRE: SIZE ........................................................80/90x21”....................100/80x17”
FRONT TYRE: PRESSURE .............................................1.0 to 1.1......................1.7 to 1.8
REAR TYRE: SIZE..........................................................100/80x18”...................130/80x17”
REAR TYRE: PRESSURE ...............................................1.2 to 1.3......................2.0 to 2.1
FRONT BRAKE: TYPE / SIZE: ...............................Wavy hydr. disc 260 mm. ....Double hydr. disc 240 mm.
REAR BRAKE: TYPE / SIZE....................................Wavy hydr. disc 218 mm. ..........Hydr. disc 218 mm.
TOTAL CAPACITY, FUEL TANK ...........................................................7,0 litres
TOTAL CAPACITY, OIL RESERVOIR ...................................................1,0 litre
COOLING LIQUID CAPACITY .............................................................0,85 litre
ENGINE
OPERATING CYCLE ..........................................................................Two stroke
BORE x STROKE............................................................................39.86 x 40 mm.
NUMBER OF CYLINDERS ......................................................................One
TOTAL CUBIC CAPACITY .....................................................................49.9 cc
MAXIM UM POWER ...................................................................8.5 CV a 9,000 rpm
COMPRESSION RATIO ..........................................................................13:1
FUEL ......................................................................................Unleaded petrol 95 octane
ADMISSION SYSTEM .......................................................................Reed valve
STARTER SYSTEM ...........................................................................Kick starter
LUBRICATION SYSTEM ......................................................................Oil pump
COOLING SYSTEM .................................................Liquid-cooled with pump, radiator and thermostat
CARBURETTOR
BRAND / TYPE ............................................................................Dell´Orto / PHVA 14
ENGINE IDLE SPEED ......................................................................1,900 ± 100
TURNS IDLE JET AIR SCREW...............................................................2 3/4
DIFFUSER DIAMETER .........................................................................14 mm.
# IDLE JET ...............................................................................................#32
# MAIN JET ..............................................................................................#71
CONICAL NEEDLE: TYPE / STD ADJUSTMENT ................................A11/4th
SLIDE VALVE ...........................................................................................#30
# EMULSIFIER TUBE ...........................................................................#211GA
CHOKE TYPE ..................................................................................MECHANICAL
# CHOKE JET ..........................................................................................#45
FLOAT ....................................................................................................3.5 gr.
GENERAL TECHNICAL SPECIFICATIONS
DRD MODELS
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What's Included?
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Fast Download Speeds
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Access PDF Contents & Bookmarks
Full Search Facility
Print one or all pages of your manual
$32.99
Models covered:
- Racer
- Xtreme
- DRD
- GPR
All models and repairs are covered comprehensively from A to Z. This workshop service repair manual encompasses all mechanical and electrical repairs. It contains an abundance of detailed pictures and diagrams to aid in the repair process. Every page is printable, allowing you to conveniently print only the necessary sections.
Whether you are a professional mechanic or a DIY enthusiast, you can purchase with complete confidence, as we ensure super-fast delivery on all orders. Our service and repair manuals are of professional quality and can be utilized multiple times without any time constraints or expiration.
FAQ: Why should I purchase this Service Repair Workshop Manual?
This manual presents repair procedures in a clear and comprehensive layout, enhancing your understanding of all engine parts and repair processes. With the knowledge provided in this manual, you will be capable of performing your own servicing and repairs.
FAQ: What models are covered in this manual?
This Service Repair Workshop Manual is model-specific and not generic. It is akin to the type of manual utilized by your local Dealer/Mechanic.
FAQ: What type of information is covered?
The manual covers routine maintenance, tune-up procedures, specifications, engine removal/installation, cylinder head/valve train, engine block, engine lubrication, and more.
FAQ: How long for delivery?
Delivery is instant upon payment through your Credit/Debit/Paypal Account. There is no shipping involved, ensuring immediate access to the manual.
FAQ: How much money will I save?
This manual has the potential to save you thousands of dollars. It equips you with the information and knowledge to undertake small jobs yourself, preventing overcharging by mechanics.
FAQ: Is this manual hard to use?
No, it is not. The manual is in .PDF format and can be easily utilized on any PC/MAC computer using Microsoft Windows, such as XP, NT, 2000, Vista, Windows 7, and more.
