Derbi GP1 125-250 c.c. Manuel de service

GP1 125-250 c.c. WORKSHOP MANUAL

9SPECIFICATIONSDESC. / QUANTITYMaximum length Maximum height Length between axlesHandlebar width Handlebar heightGP1 125 c.c.GP1 250 c.c.M434MM237MGP

99Version 250- Remove the two screws shown in the figure.- Extract the motor from its seat.REMOVING THE FLYWHEEL MAGNETO- Hold the flywheel using the

100- Line up the 2 holes on the flywheel as shown in the photo- Tighten the guide shim cylinder that is part of the specific flywheel stop key on the

101INSPECTING THE FLYWHEEL COMPONENTS- Check the integrity of the internal plastic parts of the flywheel and the Pick-Up control plate.REFITTING THE F

102- Insert the free wheel on the flywheel as shown in the pic-ture.- Hence refit the flywheel with the intermediate gear and the free wheel.- Using t

103CYLINDER ASSY. AND TIMING SYSTEMREMOVING THE INTAKE MANIFOLD- Remove the flywheel cover as described in the Flywheel cover chapter.- Loosen the 3 s

104- Loosen the tightener central screw.- Remove the 2 attachments shown in the figure.- Remove the tightener with relevant gasket.- Remove the inside

105REMOVING THE CAM SHAFT- Remove the 2 screws and the camshaft fixing bracket shown in the figure.- Remove the camshaft.- Remove pins and rockers by

106REMOVING THE VALVES- Using the specific tool with adapter, remove half-cones, plates, springs and valves.- Remove the oil guards by the specific to

107INSPECTING THE SMALL END- Using a micrometer, measure the connecting rod small end diameter.N.B.IF THE CONNECTING ROD SMALL END DIAMETER EXCEEDS TH

108- Using appropriate feeler gauges, measure the clearance between piston rings and grooves, as shown in the figure.- If such clearances exceed the l

10SPECIFICATIONSDESC. / QUANTITYENGINEEngine oil (125)Engine oil (250)Fuel tankRear hub oil~ 1100 cc~ 1200 cc~ 11 L. with reservation of 2,7 L.)250 cc

109- Take the measurement 5 mm from the base in the position shown in the figure.- Carefully clean the sealing ring housings.- Using suitable probes,

110INSPECTING THE CYLINDERVersion 250- Using a bore gauge, measure the internal diameter of the cylinder following the directions given in the figure

111INSPECTING THE PISTON RINGSVersion 125Seal rings- Insert each of the three piston rings in turn, inside the cylin-der where it still maintains its

112N.B.BEFORE REPLACING THE LININGS, MAKE SURE THAT THE PRES-CRIPTIONS RELATING TO THE SEALING RING - HOUSINGS AND PISTON - CYLINDER COUPLING CLEARANC

113CHOOSING THE GASKETCharacteristicCompression ratio - 125cc version Re: 11,50 ÷ 13:1The length «A» to be measured refers to the piston protrusion. I

114CharacteristicCompression ratio - 125cc version Re: 11,50 ÷ 13:1 The length «A» to be measured refers to the piston protrusion. It

115COMPRESSION RATIO VERSION 250CharacteristicCompression ratio version 250 Rc: 10,5 ÷ 11,5N.B.THE MEASURE «A» TO TAKE IS A PISTON PROTRUSION VALUE TH

116REFITTING THE PISTON RINGSSealing ring assembly- Place the scraper ring spring on the piston. - Install the scraper ring keeping the opening oppose

117INSPECTING THE CYLINDER HEAD- Using a rectified bar and a thickness gauge, check that the head surface exhibits no deformations or wear.- Check tha

118INSPECTING THE VALVE SEALINGS- Insert the valves into the head.- Alternately test the intake and exhaust valves.- The test should be carried out by

11SPECIFICATIONSDESC. / QUANTITY ELECTRICAL COMPONENTS10°±1° at 2000 r.p.m. - 34°±1° at 6000 r.p.m.CHAMPION RG4HCCHAMPION RG4HC12V-12AhN°1 15A / N°2

119INSPECTING THE VALVES- Check the valve stem diameter at the three points shown in the figure.- Calculate the clearance between valve and valve guid

120- Measure the sealing surface width on the valves and valve seats.Sealing surface width: after use: Intake and exhaust: 1.6 mm- If the valve sealin

121N.B.DO NOT CHANGE THE VALVE ASSEMBLY POSITION. FIT THE VALVES WITH THE REFERENCE COLOUR ON THE HALF-CO-NES SIDE (LARGER STEP CURLS).Specific toolin

122Camshaft check: Standard height Exhaust: 29,209 mmCamshaft check: Standard height Intake: 30,285 mmCamshaft check: Minimum admissible diameter Co

123-Fit the timing chain drive sprocket onto the crankshaft with the bevelled edge towards the inserting side.- Fit the timing drive chain onto the cr

124- Insert the spring with the central screw and the washer and tighten the cap at the prescribed torque- Adjust the valve clearance- Install the spa

125Version 250- Insert the timing chain guide sliding block.- Insert the centring dowels between head and cylinder, ins-tall the head gasket and the h

126- Install pins and rockers.- Lubricate the 2 rockers through the top holes.- Lubricate the 2 connections and insert the camshaft into the head with

127Install the containment bell using the balance weight fixing screw as a reference.- Tighten the central fixing screw at the prescribed torque.Locki

128REFITTING THE ROCKER-ARMS COVER- Reassemble the head cover by locking the 5 screws to the prescribed torque.- Pay attention to correct positioning

12Front wheel rimRear wheel rimFront tyreRear tyreTyre pressure front wheel (cold)Tyre pressure rear wheel (cold)Tyre pressure rear/front wheel (drive

129CRANKCASE - CRANKSHAFTSPLITTING THE CRANKCASE HALVES Version 125 Remove the following assemblies: transmission cover

130- Remove the crankcase gasket.- Remove the two screws and the internal cover shown in the diagram.CAUTIONWHILE OPENING THE CRANKCASES AND REMOVING

131If the driving shaft - crankcase axial clearance is higher than the standard value and the driving shaft exhibits no irregula-rity, the problem is

132- Check the axial clearance of the connecting rod.- Check the radial clearance of the connecting rod.- Check that the axial clearance containment s

133CharacteristicDriving shaft - case axial clearance: Standard clearance 0,15 ÷ 0,40 mmDriving shaft - connecting rod axial clearance: Standard clear

134N.B.ENCH ENDS ARE NOT RECTIFIABLE.Specific tooling 020074Y Crankshaft aligning toolCharacteristicAlignment check: Max admissible displacement: A =

135N.B.THE HEAD LUBRICATION CHANNEL IS PROVIDED WITH A SHUTTER JET; THIS GIVES A «LOW PRESSURE» HEAD LUBRI-CATION; THIS CHOICE WAS MADE TO REDUCE THE

136- The brass housing hole is in the only category reported below.- The standard brass diameter after driving is variable on the basis of a coupling

137N.B.TO KEEP SUCH POSITION OF THE BRASSES ON THE CRANK-CASE, DRIVING IS FORCED ON STEEL RINGS INSERTED IN THE CASTING OF BOTH HALF-CRANKCASES.N.B.DO

138- Insert the precleaner on the engine with relative plug. Lock to the prescribed torque.Locking torques (N*m)Engine crankcase inside head screws (t

13Flowing through the hole shown in the figure, the air reaches the second filter, «B», At this point, the tiltered air enters the membrane device, so

139LUBRICATIONCONCEPTUAL DIAGRAMSLubrification circuitUCORecupero gas motoreBy-pass valveCarico olioOil pumpLivelo olio nella coppaPrefiltro a reteCar

140OIL PRESSURE CHECK- After removing the flywheel cover as explained in the Flywheel chapter, disconnect the minimum oil pressure swit-ch electric co

141- Install the base of the specific tool on the oil seal using the screws provided.Specific tooling 020622Y Transmission-side oil guard punch. - Sc

142- Place the cover on the engine crankcase, apply the three screws with copper washers and install the cover into its seat by the three screws.- Tig

143For version 125 to proceed with the assembly of new paraoil a side they fly by means of the indicated specific tool like in photoN.B.FAILURE TO USE

144INSPECTION- Remove the two screws and the oil pump cover.- Remove the inside rotor retaining snap ring.- Remove the rotors and carefully wash them

145REFITTING-Check that the pump body-shaft is free from wear.- Check that the pump cover exhibits no wear or scratching.- In case of non-conforming v

146- Remove the spring, the by-pass piston, the gasket and the centring dowels shown in the second figure.INSPECTING THE BY-PASS VALVE- Check the free

147SAS VALVEINSPECTING THE ONE-WAY VALVE- Remove the SAS valve- Temporarily install the rubber sleeve at the outlet of the SAS valve ensuring its seal

148INSPECTING THE CUT-OFF- Remove the SAS valve- Connect the pump in vacuum position (VACUUM) to the CUT - OFF valve vacuum inlet- Apply a vacuum of o

14The working principie ofthe SAS for Quasar 250 cc Euro 2 engines is entirely similar to the SAS employed on 2-stroke engines. The main differences a

149FUEL SUPPLYREMOVING THE CARBURETTORKEHIN- To disconnect the carburettor from the engine, it is neces-sary to move the air filter and remove the gas

150- Remove the clamp and the cap with the membrane cham-ber aeration filter.- Remove the 4 fixing screws shown in the figure and the vacuum chamber c

151Loosen the coupling by 1/8 turn and remove it, remove the spring and the vacuum valve pin.Remove the 4 screws shown in the figure.Remove the basin

152- Suitably support the carburettor and remove the float pin by a hammer from the gas control side.- Remove the float and the pin.- Remove the maxim

153Remove the spray nozzle.N.B.THIS OPERATION IS REQUIRED TO PREVENT LOSING THE SPRAY NOZZLE DURING THE CARBURETTOR CLEANING OPE-RATIONS. IF THE SPRAY

154N.B.THIS OPERATION IS REQUIRED TO PREVENT LOSING THE SPRAY NOZZLE DURING THE CARBURETTOR CLEANING OPE-RATIONS. IF THE SPRAY NOZZLE IS FORCED INTO I

155N.B.DURING THE COVER REMOVAL, BE CAREFUL TO THE SUDDEN PROJECTION OF THE SPRING.Remove the vacuum valve with the membraneLoosen the coupling by 1/8

156Remove the basin with the pickup pump, control and gasket.Remove the pickup pump with ring nut, the casing, the O-Ring and the spring from the basi

157Remove the cap conveying the fuel to the starter nozzle as shown in the figure.- Remove the maximum nozzle.- Remove the emulsifier.Remove the spray

158Remove the spray nozzle. - Remove the minimum flow screw with the O-Ring, washer and spring.- Remove the 2 fixing screws, the cover, the spring and

15Depresione typePrinting on the bodyDevice CUT-OFFMax. jetMinimum jetMax. air jetMinimum air jetIdle mixture adjusment screw initial openingConical p

159REFITTING THE CARBURETTORKEHIN- Before proceeding to reassembly, carefully clean the car-burettor body using fuel and compressed air.- Be especiall

160- Check that the throttle valve and the shaft exhibit no abnormal wear.- Check that the pin seat exhibits no abnormal wear.- In case of anomalies,

161- Check that the float exhibits no wear on the pin seat or on the plate in contact with the pin, or fuel infiltrations.- In case of anomalies, repl

162- Wash and blow the flow screw.- Check that the screw is free from deformation and/or oxida-tion.- Assemble the spring on the screw.- Tighten the f

163- Check that on the carburettor body there are 5 closing balls of the processing ducts.- Check that the matching surfaces with the basin and the me

164LEVEL CHECKKEHIN- Place the carburettor tilted as shown in the figure,- Check that the reference on the float is parallel to the basin matching sur

165- Remove the basin drainage screw and wash and blow the basin, be especially careful to the cleaning of the pickup pump intake and delivery valve.-

166- Check that the pickup pump control rocker is free from ab-normal wear.- Check that the rocker travel end screw protrudes by 3.2 mm.- Check that t

167- Replace the spring with the pin lock.- Replace the vacuum chamber cover checking the proper positioning of the spring into the housing on the cov

168WALBRO- Check that the pin exhibits no wear and that the lock is in the third notch out of 3.- Check that the vacuum valve exhibits no scratches on

16Starter jetStarter pin diameterStarter device resistanceChokeThrottie valveChoke máximum coneSPECIFICATIONDESC. / QUANTITYCARBURADOR WALBRO50Ø 1,78~

169INSPECTING THE AUTOMATIC CHOKE DEVICE- Check that the automatic starter piston exhibits no scrat-ches or oxidation.- Check that the piston slides f

170KEHIN- Check that the automatic starter piston exhibits no scrat-ches or oxidation.- Check that the piston slides freely into the seat.- Check that

171WALBRO- Check that the automatic starter piston exhibits no scrat-ches or oxidation.- Check that the piston slides freely into the seat.- Check tha

172Fork assemblyM8x30 securing boltR-Hydraulic system with right-handSafety ringGuide bushGuide bush washerSealRingDust guardR-Fork arm assemblyM10x30

173DISMANTLING FRONT SUSPENSIONATTENTIONTO CARRY OUT THE PROCESS OF DISMANTLING THE FOR-KS WITHOUT REMOVING THEM FROM THE BOTTOM PLATE. TO DO SO, HOLD

174Extract the spring and the preload spacer.- Extract the oil seal dust guard together with its security circlip.- Firmly separate the bar from the f

175- Proceed with cleaning and degreasing all the front sus-pension components, so that they can be subsequently chec-ked.INSPECTING THE FRONT FORKS-

176Reassemble the assembly, paying special attention to the tig-htening of the fork stem, as well as the fitting of the oil seal, putting a little oil

17712345678910111213141516171819202223242526Stand stop rubberO-ring10M 150x130 hexagonal bolt10M 150 hexagonal nutD10 washer2627282930Shock absorber10

1781234567891011121314151617181920Front engine support14Mx200x70 hexagonal boltD15 flat washer14M200 hexagonal nutEngine support separator bushNeedle

17CARBURATTOR WALBROVersion 250Depression typePrinting on the bodyCUT-OFF deviceMax jetMinimum jetMax air jetMínimum air jetGas valve springIdle mixtu

179DISMANTLING1. Place the motorcycle on a flat surface.WARNINGSUPPORT THE MOTORCYCLE FIRMLY, IN SUCH A WAY THAT THERE IS NO RISK OF IT FALLING.Before

180SWING-ARMREMOVAL- Put the vehicle on the centre stand.- Suitably support the engine.- Unscrew the nut shown in the figure and pull out the pivot on

181CHECKING THE SWINGING ARM- Accurately grease the roller cages-Insert the spacers- Install the two halves with their respective bolts in the posi-ti

182OVERHAUL- Remove the spring clip shown in the picture.- Suitably support the silencer mounting bracket.- Using special tool, extract bearing from i

183CENTRE-STAND- Remove the two stand return springs.- Unscrew the nut shown in the figure.- Remove the pivot from the right-hand side.- Remove the st

184REAR WHEEL 125 C.C.Front wheelTyreValve, tyreBearingBearingFront wheel axleBushWasherNutProtectorCoverFront brake discScrewScrewBrake caliperSpring

185REAR WHEEL 250 C.C.Front wheelTyreValve tyreBearingBearingFront wheel axleBushWasherNutProtectorFront brake discFront brake discScrewBrake caliperB

186DISMANTLINGWARNING- ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING.- PLACE THE MOTORCYCLE ON A FLAT SURFACE.1. E

1873. Check:- Spokes.Warps/damage => Replace.4. Measure:- Distortion of the front wheelAbove that specified => Replace.Distortion limits for the

188DISMANTLING THE FRONT DISK CALLIPER- Loosen the banjo bolt (1) from the bottom end of the brake pipe and tighten it slightly.- Unscrew the calliper

18CHASSIS TIGHTENING TORQUES1,7÷1,91,7÷1,94,5÷5,54,5÷5,57÷83÷43÷41,7÷1,91,7÷1,93÷3,56÷6,59÷130,8÷13÷41,7÷1,91÷1,31,7÷1,9 0,8÷11,7÷1,91,7÷1,90,35÷0,457

189Extracting the front brake pads.- Remove the front brake calliper (see “Dismantling the front brake calliper” in this chapter).Extract:- Pad spring

190N.B.THE MASTER CYLINDER (1) IS INCORPORATED INTO THE FRONT BRAKE LEVER ASSEMBLY.- EXTRACT THE SCREWS (2) AND THE FRONT BRAKE LEVER ASSEMBLY.PRECAUT

191Checking the brake calliper main cylinder:- Check that the anti-dust boots are not damaged.If they are, change them.- Check that the piston return

192Brake disk distortion:- Raise the motorcycle on the jack so that the tyre is clear of the ground.- To check the front disk, turn the handlebars com

193Purge the air completely from the master cylinder using this procedure.- Remove the transparent plastic cap from the bleed nipple and place the oth

1943) DO NOT MIX TWO TYPES OR BRANDS OF FLUID FOR USE IN THE BRAKE. THIS LOWERS THE BRAKE FLUID EVA-PORATION POINT AND MAY RESULT IN THE BRAKES NOT W

195ASSEMBLING THE FRONT WHEELReverse the “DISMANTLING” procedures. Take care with the following points:1. Lubricate:- Front wheel axle.- Bearing.- Ret

196REAR WHEEL 125 C.C. 5 C.C.Rear rimTyreValve, tyrePinBushBushNutNutPinBrake disc bracketScrewWasherRear brake discScrewNutBracketScrewWasherWasherRe

197REAR WHEEL 250 C.C. 50 C.C.Rear rimTyreValve, tyrePinBushBushNutNutPinBrake disc bracketScrewWasherRear brake discScrewNutBracketScrewWasherWasherR

198DISMANTLINGWARNING- ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING.- PLACE THE MOTORCYCLE ON A FLAT SURFACE.- Pl

1DERBI - NACIONAL MOTOR, S.A.U., manufacturer of DERBI motorcycles and mopeds, has produced this manual with the aim of documenting and simplifying as

19Screw clamping manifold to silencerScrew clamping heat shield to silencerExhaust gas intake screwScrew fixing silencer support arm to crankcaseExhau

199Fitting the rear calliper- Fit the bottom end of the flexible brake pipe and the calliper.- Tighten the brake banjo bolt.- Check brake fluid level.

200WARNINGDO NOT ATTEMPT TO RIDE THE MOTORCYCLE UNTIL THE BRAKE PEDAL IS OPERATING FULLY. PUMP THE LEVER UN-TIL THE PADS ARE AGAINST THE DISK. IF NOT,

201Checking the rear main cylinder (visual check)- Extract the main cylinder (consult “Extracting the rear main cylinder” in this section).- Dismantle

202Brake disk wear- Measure the thickness of the disks (A) at the point where they are most worn.- If the disk is more worn than specified in the serv

203Extract:- Bolts (1).- Reservoir cap (2).- Fill the reservoir with brake fluid up to the top reservoir line.- With the cap removed, pump the brake l

204WARNINGWHEN WORKING WITH THE DISK BRAKE, TAKE THE FO-LLOWING PRECAUTIONS:1) NEVER RE-USE BRAKE FLUID.2) DO NOT USE FLUID FROM A CONTAINER THAT HA

205INSPECTING THE REAR WHEEL1. Inspect:- Rear wheel axle- Rear wheel- Rear wheel bearings- Retaining ringsSee the “WHEEL AND REAR BRAKE” section2. Mea

206CIRCUIT DIAGRAMENGINE 250C CU GABCDSPECIFICATIONDESC. / QUANTITYENGINE COOLING CIRCUITCarburettor heating circuitThermostat with by-passExpansion

207CIRCUIT DIAGRAMENGINE 125C CU GABCDSPECIFICATIONDESC. / QUANTITYENGINE COOLING CIRCUITCarburettor heating circuitThermostat with by-passExpansion

208WATER PUMP - OVERHAULENGINE 125- In case of noise of the bearings or fluid leaks from the insi-de drainage hole, proceed to the water pump overhaul

20Tappet adjustment lock nutTiming chain tightener sliding block screwsStart up mass bell screwsTiming beit tightener support screwTiming beit tighten

209- Using the thermal gun, heat the flywheel cover from the internal side.- Place the flywheel cover on the ring base in a way similar to the removal

210N.B.PERFECTLY CENTRE THE PUNCH ON THE IMPELLER. MOVE THE SHAFT AND CHECK THAT THE FLYWHEEL COVER TUR-NS IN PLANE. FAILURE TO OBSERVE THIS REGULATIO

211The pump can be services using the special tool and a press. The special tool is designed to be used with the presses most commonly found in worksh

212Remove the ceramic seal from the pump shaft. Using a screwdriver, remove the ceramic ring and sealing gasket from the flywheel cover.N.B.IN THE EVE

213Before you reassemble, wash all the components and conti-nue with the following checks.Flywheel cover: Check that there are no cracks or oxidation

214Heat the flywheel cover using the heat gunN.B.IF THE JOB IS PERFORMED WITH THE STATOR MOUNTED, HEAT FROM THE EXTERNAL SIDE OF THE COVER.Specific to

215Position the flywheel cover on the press using the support base for the bearings that is part of the special tool. Install the special punch with t

216Remove the special punch from the press piston and support the flywheel cover from the impeller side with it.Put the new oil seal on the special pu

217Lubricate the oil seal with motor oil.

218ELECTRICAL SYSTEM GP1 125-250CC SS G 550O - OrangeGR - GreenB - BlackBR - BrownW - WhiteG - GrayY - YellowBL - BlueR - RedP - PinkVI - Violet

21Engine crankcase coupling screwsStarter motor screwsCrankcase timing cover screwsNAMETORQUE IN NmENGINE CRANKCASE AND SHAFT4 ÷ 611 ÷ 1311 ÷ 133,5 ÷

219CHECKING CONNECTORSCheck for corrosion, damp etc. in the connectors.1. Disconnect:- Connectors2. Dry each of the terminals with compressed air.3. C

220INSPECTION STEPSUsing a multimeter, check the circuit between the terminals to make sure that they are correctly connected. Replace the component i

221IGNITIONVoltage regulator.Battery15A fuseCDIUDigital instruments unitFanFan thermostat switchHall sensorOil pressure sensor Petrol reserve sensor T

222LIGHTS AND AUTOMATIC CHOKEAlternatorVoltage regulatorAutomatic chokeRear lightDigital instruments unitFront sidelight bulbsDipped headlight bulbsMa

223RECHARGING THE BATTERY AND STARTINGAlternatorVoltage regulator15A fuseBatteryStarter relayStarter motorStarter switchSTOP buttonEngine stopSwitchC

224SENSORS AND INDICATORSVoltage regulatorBattery15A fuseCDIUDigital instruments unitFanFan thermostat switchHall sensorOil pressure sensorPetrol rese

225TURN INDICATORS AND HORNCDIUBattery15A fuseSwitchDigital instruments unitHornHorn buttonTurn indicator bulbsTurn indicator buttonDiode boxEngine st

226IGNITION CIRCUITIgnition systemOnce the ¡mmobilizer system has been enabled, it is possible to have the spark at the spark plug by the H.V. coil an

227- H.T. coil secondary circuit checkDisconnect the spark plug cap from the H.T. cable and mea-sure the resistance between the end of the H.T. cable

228STATOR CHECKDisconnect the connector from the voltage regulator and check the presence of continuity between each yellow wire with the other two.El

22OVERHAUL DATAASSEMBLY CLEARANCESCYLINDER - PISTON ASSYCylinderCylinderPistonPistonCylinder first uprat.Cylinder first uprat.Piston first uprat.Pisto

229RECHARGE SYSTEM VOLTAGE CHECKThe battery recharge system consists of a threephase gene-rator and a permanent-magnet flywheel.The generator is direc

230FUSESThe electrical system is protected by a fuse located on the r.h.s. of the battery bay. To replace it, lift the seat, remove the battery access

231- Upturn the electrolyte container with the six closing surfa-ces aligned with the six battery filling holes.- Push the container down with enough

232BATTERY-INITIAL CHARGEAccepting that a battery requiring no maintenance can be used only once it has been filled with electrolyte, the battery may

233TAKE CAREKEEP THE BATTERY AWAY FROM SPARKS OR NAKED FLA-MES DURING THE CHARGING PROCESS, SINCE THE BAT-TERY GIVES OFF AN EXPLOSIVE MIXTURE OF HYDRO

234N.B.CARRY OUT THE MEASUREMENT WITH A DIGITAL VOLT-METER (A) THAT CAN READ VOLTAGES WITH DECIMAL FI-GURES.* IF THE READING IS BELOW THAT SPECIFIED,

235

236POSSIBLE CAUSEWORKPOOR PERFORMANCEENGINEDirty-carburettor; feeding pump or vacuum cock failureExcessive scaling in the explosion chamberWrong timin

237POSSIBLE CAUSEWORKREAR WHEEL TURNING WITH IDLE ENGINEIdle rpm too highClutch failureAdjust the engine idle speed and the CO%, if requi-red.Check cl

238POSSIBLE CAUSEWORKWorn valve guidesCheck and replace the head unit if requiredEXCESSIVE OIL CONSUMPTION / SMOKE UPON EXHAUSTPOSSIBLE CAUSEWORKSTART

23CylinderCylinderPistonPistonNAMEPLAY72+0,018±0,01072+0,018±0,01071,967±0,01471,967±0,014INITIALABCDCYLINDER71,990 ÷ 71,99771,997 ÷ 72,00472,004 ÷ 72

239POSSIBLE CAUSEWORKDefective feeding circuit Check the feeding pump, the vacuum inlet, and the duct seal, replace if required.ENGINE TENDS TO CUT-OF

240POSSIBLE CAUSEWORKFloat level Restore the level in the basin by bending the fuel inlet pin thrusting reed on the float so as to have the float para

241POSSIBLE CAUSEWORKCutoff valve of the secondary air device not workingReplace the secondary air deviceSAS MALFUNCTIONSSECONDARY AIR DEVICE ANOMALIE

242POSSIBLE CAUSEWORKRubber gaskets expanded or sealedReplace the gaskets.BRAKES OVERHEATINGPump compensation holes cloggedClean carefully and blow wi

243POSSIBLE CAUSEWORKElectronic ignition device failure.With the key switch set to «ON» connect the jumpers 1 (Blue-Black) and 5 (Red/Blue) on the con

244NOISY SUSPENSIONPOSSIBLE CAUSEWORKNoisy suspension If the front suspension is noisy, check: the front shock absorber efficacy, the condition of the

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24OVERSIZES ENGINE 250NAMEDESCRIPTION DIMENSIONS72 x 1,572 x 172 x 2,5INITIALSAAA0,15 ÷ 0,300,20 ÷ 0,400,20 ÷ 0,40QUANTITYCompression liningScraper ri

25FITTING CLEARANCEDriving shaft/case axial clearance: Standard clearance 0,15 ÷ 0,40mm (cold engine). CARNCSHAFT - CRANKCASE AXIAL CLEARANCE/CARTERNA

26SLOT PACKING SYSTEMCharacteristicsCompresion ratio - 125cc verion Rc: 11,50÷13:1The length «A» to be measured refers to the pistón protrusion. It i

27SLOT PACKING SYSTEMCharacteristicsCompresion ratio - 125cc verion Re: 11,50÷13:1The length «A» to be measured refers to the pistón protrusion. It i

28SISTEMA DE MONTAJE DE ESPESORESCaracterísticas TécnicasRelación de compresión versión 250 Re: 10,5-11,5N.B.THE MEASURE «A» TO TAKE IS A PISTÓN PROT

29OVERSIZES ENGINEOVERSIZESNAME DESCRIPTION DIMENSION57,2 x 157,2 x 157,2x2,557,4 x 157,4 x 157,4 x 2,557,6 x 157,6 x 157,6 x 2,5INITIALSAAAAAAA

30PPREPARATION FOR REMOVAL AND DISMANTLING1. Remove all the dirt, grime, dust and other foreign material before removing and dismantling.2. Use proper

31REPLACEMENT PARTS1. Use only genuine DERBI spare parts. For all lubricationtasks use oils and greases recommended by DERBI. Othermakes make seem sim

32LOCKING RINGS1. Examine all the locking rings carefully before fitting. Always replace the gudgeon pin circlips after every use. Re-place distorted

33STORES CODEIMAGEDESCRIPTION15mm guide17mm guide42 x 47mm hub bearing fitting adaptor20mm guideEngine supportFlywheel extractorOil presure gauge conn

34Valve oil seal extractorOil pressure gaugeValve sealing ring drift52 x 55mm adaptor25mm guideAdapter 28 x 30mmSTORES CODEIMAGEDESCRIPTION020382Y0110

35Handle for punchesDriven half pulley spring com-pressor toolStroboscopic gun fot two-and four-stroke enginesBellDriving pulley stop wrenchImmobilize

36Crankcase detachment platePin retainers installation tool (engine 125cc)Piston position check supportPiston fitting forkFlywheel-side oil guard punc

37Tool for removing valve cotters equipped with part 01210mm guidePulley stop wrenchWater pump overhaul toolPump32 x 35 mm adaptorMultimeter adpater (

38Digital rpm counterCrankshaft aligning toolPliers dor snap ringsPin retainers installation toolTransmission-side oil guard punchAdapter ring45 x 55

3INTRODUCTIONGENERAL INFORMATIONGENERAL TECHNICAL DATARECOMMENDED TOOLSPERIODIC MAINTENANCE DISMANTLINGSEAT SIDE TRIMCOWLINGCOWLING BOTTOM COVERWATER-

3915mm pliersAdapter ringDrift Ø 15 Drift Ø 18Slient-block installation / remo-val toolFlywheel stop keyFlywheel estractorDriving pulley stop keySTOR

40MAINTENANCE CHARTC CCooling Fluid ReplacementBrake fluid ChangeEVERY 2 YEARSACTIONEVERY 2 YEARSEngine oil ReplacementHub Oil ReplacementOil fi

41Engine oil ReplacementHub oil level CheckSpark plug/Electrode gap Check/ChangeAir Filter CleaningOil filter ReplacementIdling speed S&

42ACTIONAT 18.000 KM AND 54.000 KMEngine oil Replacement (125)Hub oil level CheckSpark Plug/Electrodes distance CheckAir Filter Cleaning Oil fi

43Electrical system and battery CheckHeadlight AdjustTires-inflation and wear Check‘ Vehicle and brake test Road testTransmission Belt Check

44Cooling fluid level CheckRadiator External cleaning/CheckSteering AdjustBrake levers GreaseBrake pads Check condition + wearFlexible brake

45Transmissions LubricateNuts, bolts and fasteners CheckSuspensions CheckElectrical system and battery CheckHeadlight AdjustTires-inflation and w

46ENGINE OILENGINE OIL 125 C.C.ENGINE OIL 250 C.C.HUB OIL LEVERDRIVE BELT 125 C.C.DRIVE BELT 250 C.C.TRANSMISSIONOIL FILTER 125 C.C.OIL FILTER 250

47CARBURETTOR- Disassemble all carburettor components, accurately wash them in solvent, then dry them with compressed air. To ensu-re thorough cleanin

48CHECKING THE SPARK ADVANCE- To check the ignition advance, use the stroboscopic lamp with induction collet connected to the spark plug power su-pply

4REFITTING THE CLUTCH REFITTING THE DRIVEN PULLEYDRIVE-VELTREMOVING THE DRIVING PULLEYINSPECTING THE ROLLERS CASEREFTTING THE DRIVING PULLEYREFITTING

49- Remove the transmission cooling air inlet, shown in the pic-ture.- Using a screwdriver rotate the fan, mounted onto the drive pulley, until the ma

50- Check that the advance degrees match the revolution speed as indicated in the tables.- In case of abnormal values, check the Pick-Up and the contr

51SPARK ADVANCE VARIATIONSPECIFICATION DESC./QUANTITYFirst threshold : 9600 ±50Second threshold : 9800 ±50Tripping thresholdRestoration thresholdSpark

52SPARK PLUG- Put the vehicle on the central stand.- Open the door on the left side of the vehicle by levering in the recess in the lower part of the

53HUB OILCheck that there is oil in the rear hub. (quantity of oil contai-ned ~ 250 cc). Proceed as follows in order to check the hub oil level:1) Tak

54CHECK- Move the vehicle to a flat ground and rest it on the stand.- Unscrew the oil bar, dry it with a clean cloth and reinsert it, screwing it in t

55N.B.CHECK AND IF NECESSARY BLOW THE AIR FILTER EVERY 6,000 KM. DIRECT THE AIR JET FROM THE INSIDE TO THE OUTSIDE OF THE FILTER (I.E. IN THE OPPOSITE

56ENGINE OIL REPLACEMENTThe engine oil should be replaced after the first 1,000 km, and then every 6,000 km for the 125cc version and 12,000 km for th

57Perform this operation when the engine cold, as des-cribed below:1) Put the vehicle on its central stand on a flat surface.2) Unscrew dipstick “A”,

58OIL PRESSURE WARNING LIGHTOil pressure warning light. A warning light on the instrument panel comes on when the ignition key is turned to the “ON” p

5INSPECTING THE PISTON RINGREMOVING THE PISTON RINGCHOOSING THE GASKETCOMPRESSION RATIO VERSION 250REFITTING THE PISTON RINGSREFITTING THE CYLINDERINS

59CHECKING THE VALVE CLEARANCE-To check the valve clearance, you have to make the point references coincide-Check that the clearance between the valve

60BRAKING SYSTEMLevel checkProceed as follows:- Rest the vehicle onto its centre-stand and align the han-dlebars;- Check the liquid level through the

61HEADLIGHT ADJUSTMENTProceed as follows:1. Position the vehicle in riding conditions, and with the tyres inflated at the prescribed pressure, on a ho

62- Remove the two screws shown in the picture.- Remove the filter shown in the picture.- Inspect the gasket.- Ensure the SAS filter box is not cracke

63- Ensure the SAS filter box is not cracked or deformed.- Inspect the packing.-Accurately clean external and internal filters. In the case of break-u

641. SEAT SIDE TRIM• Extract the 3 securing screws (2 Philips 3.6x14 self-tappers and one 5x16 Allen M3) from each cover.2. COWLING• Extract the 6 scr

653. LOWER COWLING COVER• Extract the 2 securing screws (Philips 6x16 with was-her)N.B.TO CONTINUE WITH THE HELMET HOLDER WE NEED TO CONTINUE DISMANTL

666. SHIELD INNER COVER• Extract the 2 screws (5x12 Allen M3).• Extract the 3 top screws (2 Philips 3.6x14 self-tappers and one6x16 Allen screw with w

67• After extracting the 6 side screws and the central (Allen M3 5x12) screw from the tank cover, lift up the tank cover.8. HELMET CARRIER• Remove the

689. FOOTRESTS• Remove the 5 securing screws (2 Philips 6x16 with large washer, 2 Philips 6x16 with small washer and 1 Philips 4.8x25 self-tapper), a

6FORK, SHOCK ABSORBER. ENGINE SUPPORT AND STANDDISMANTLING FRONT SUSPENSIONINSPECTING THE FRONT FORKSDISMANTLINGINSPECTIONSWING-ARMCHECKING THE SWININ

69EXHAUST ASSY. REMOVAL- Unloose the two fixings of the exhaust manifold on the head.- Unloose the 3 screws fixing the muffler to the supporting arm.-

70- Remove the throttle cable.- Detach the air filter bellow and manifold shown in the fi-gure.- Detach engine earth cable.- Disconnect the electrical

71AUTOMATIC TRANSMISSIONTRANSMISSION COVERTo remove the transmission cover it is necessary to remove the plastic cover first, using a screwdriver on t

72- Remove the 5 screws located on two different surfaces and the case.REMOVING THE DRIVEN PULLEY SHAFT BEARING- Remove the snap ring from the cover i

73BAFFLE ROLLERPLASTIC ROLLER- To reassemble, install the roller with the containment edge on the engine crankcase side.- Tighten the wrench at the pr

74Checking the bell working surface eccentricity- Install the bell on a driven pulley shaft using 2 bearings (inside diameter 15 and 17 mm).- Lock usi

75- Make sure that the clutch is perfectly inserted into the adapter ring before proceeding to release and tighten the clutch nut.- Using the specific

76INSPECTING THE CLUTCH- Check the thickness of the clutch mass friction material.- The masses must exhibit no traces of lubricants; in that case, che

77REMOVING THE DRIVEN HALF-PULLEY BEARING- Check that there is no wear and/or noise; if not, replace.- Remove the lock ring using two flat blade screw

78Version 250- Measure the pulley bushing outside diameter.- Check that the contact surface with the belt is free from abnormal wear.- Check the rivet

7SENSORS AND INDICATORSTURN INDICATORS AND HORNIGNITION CIRCUITSPARK PLUGSTATOR CHECKVOLTAGE REGULATOR CHECKFUSESDISMANTLING THE BATTERYBATTERY - INIT

79- Check that the surface of contact with the belt does not show abnormal wear.- Check the functionality of the riveting.- Check the planarity of the

80REFITTING THE DRIVEN PULLEYVersion 125- Insert the new oil guards and O-Rings on the mobile half-pulley.- Slightly grease the O-Rings (A) shown in t

81Version 250- Insert the new oil guards and O-Rings on the mobile half-pulley.- Slightly grease the O-Ring «A» shown in the figure.- Install the half

82REFITTING THE CLUTCH- Support the driven pulley spring compressor specific tool with the control screw in vertical axis.- Arrange the tool with the

83N.B.DURING THE SPRING PRE-LOADING STEP, BE CAREFUL NOT TO DAMAGE THE SPRING PLASTIC ABUTMENT AND THE BUSHING THREADING.N.B.FOR DESIGN REASONS, THE N

84- Insert the pulley unit with the belt into the tool.- Slightly pre-load the spring.- Make sure that the clutch is perfectly inserted into the adap-

85REFITTING THE DRIVEN PULLEY- Reinstall the clutch bell and the spacer.DRIVE-BELT- Ensure the drive-belt is not damaged.- Check the drive-belt width.

86REMOVING THE DRIVING PULLEYDriving pulley removal (125)- Using the specific tool, remove the nut with the built-in spring washer, the drive for the

87- Remove the fixing nut and washer.- Remove the fixed driving half pulley.INSPECTING THE ROLLERS CASE- Ensure the internal bearing, shown in the fig

88Sliding shim cylinder: Standard Diameter Ø 25,959 - 25,98 mmSliding shim cylinder: Min. Allowed diameter Ø 25,95 mmRoller (125cc): Standard diamet

8REGULATIONSThis section describes the machine’s general safety and maintenance work rules.SAFETY REGULATIONS- In the event of having to carry out wor

89- Turn the engine by hand to obtain a minimum tension of the belt.CAUTIONIT IS VERY IMPORTANT TO INSTALL THE FIXED DRIVING HALF-PULLEY WITH THE BELT

90- Replace the steel washer and the driven pulley nut.- Tighten the nut at the prescribed torque using the lock wrench and the dynamometric wrench to

91REMOVING THE HUB BEARINGS- Check all bearings (wear, clearance and noise). In case of anomalies, proceed as follows.- To remove the 3 15-mm bearings

92REMOVING THE DRIVEN PULLEY SHAFT BEARING- If you have to remove the driven pulley shaft, the relevant bearing and the oil guard, remove the transmis

93REFITTING THE WHEEL AXLE BEARING- Place the hub cover on a wooden surface. - Warm the cover case by the specific thermal gun.- Install the wheel axl

94Specific tooling 020151 Y Air heater 020376Y Handle for punches 020359Y 42 x 47 mm hub bearing fitting adaptor 020412Y 15 mm guide

95REFITTING THE HUB BEARINGS - Install the 3 shafts in the engine crankcase as shown in the figure.

96Version 125- Remove the clamp fastening the coupling to the cylinder.- Remove the 10 clamps.- Remove the flywheel cover.

97REFITTING THE STATORVersion 125- Replace stator and flywheel performing the operations for removal in the reverse order and tighten the fixing screw

98- Position the keying clamp on the driving shaft and direct the end as shown in the figure.- Position the water pump shaft by referring to the trans