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um UXPW125 Service Manual

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UXPW125 ENGINE SERVICE MANUAL
AND EFI DIAGNOSTIC

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Summary of Contents for um UXPW125

  • Page 1 UXPW125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC...
  • Page 2 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC INDEX 1、MAIN TECHNICAL PARAMETERS 2、GENERAL MAINTENANCE 3、LUBRICATION SYSTEM 4、CYLINDER HEAD PARTS MAINTENANCE 5、CYLINDER BLOCK AND PISTON 6. RIGHT COVER/ CLUTCH/ BALANCING GEAR/ GEARSHFT 7. LEFT COVER/ STARTING MOTOR SYSTEM/ MAGNETO 8. CRANKCASE (EXTRACTION AND INSTALLATION) 9.
  • Page 3 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC MAIN TECHNICAL PARAMETERS Item Specification UXPI 125 Model number Single-cylinder, water-cooling, Type four-stroke, SOHC Bore X stroke Φ52.4×57.8mm Piston Displacement 124.6 C.C. Compression ratio 11：1 （ 5°BTDC） Open Engine （37°ABDC） Close Valve （50°BBDC）...
  • Page 4 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 1.1 Maintenance Parameters： Item Standard Service Limit Specification SJ 10W/40 1.2 L when filter is not removed Engine oil when filter is removed Capacity 1.1 L when engine is completely 1.2 L 0.04-0.06mm 0.10mm Valve...
  • Page 5 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 1.3 Cylinder and Piston unit: mm Item Standard Service Limit Inner diameter of cylinder Φ52.400～φ52.410 Φ52.5 Cylinder Cylindricity 0.004 0.10 Planeness of cylinder face 0.03 0.10 Outer diameter of piston Φ52.38～φ52.39 Φ52.3 Inner diameter of piston pin hole φ14.002～14.008 φ14.04...
  • Page 6 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 1.4 Clutch unit：mm Item Standard Service Limit 41.1-41.9 Clutch Spring Free Length 2.92-3.08 Friction Plates Thickness Clutch flatness of clutch driven plate 0.20 Φ23.000 ～φ23.021 Driven gear inner hole diameter φ23.08 Collar diameter Φ22.960～φ22.975 Φ22.93 Shaft sleeve...

  • Page 7: Table Of Contents

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC GENERAL MAINTENANCE 2.1. ENGINE MAINTENANCE CYCLE ......................- 8 - 2.2. ENGINE MAINTENANCE STANDARD S ....................- 8 - 2.3. T ORQUE STANDAR S ........................- 8 - 2.4. SPARK PLUG MAINTENANCE ......................- 9 - 2.5.

  • Page 8: Engine Maintenance Cycle

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 2.1 Engine Maintenance Cycle Cycle Travel Travel Kms（×1000 Km） Inspection Maintenance Spark Plug Valve Clearance Engine Oil Fuel Filter Oil Strainer Oil Filter Idle Speed I: Inspect, clean, adjust, lubricate or replace if necessary. C: Clean R: Replace IMPORTANT NOTE: to guaranty the perfect function of fuel injection system, the fuel filter must...

  • Page 9: Spark Plug Maintenance

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 2.4 Spark Plug Maintenance Suggested Spark Plug Reference Standard Use CPR8EA-9(NGK) High RPM Extreme Use CPR9EA-9(NGK) Note: Using wrong spark plug specification can damage the engine. If the lateral and center electrode have erosion or covered with accumulation of carbon, the spark plug shall be cleaned or replaced.

  • Page 10: Valve Clearance Adjustmen

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Valve Clearance Adjustment Too large valve clearance will result in noise and ultimately in damage of engine. Too small valve clearance or no clearance will result in that valves are not closed tightly, thus causing valve damage and power loss of the engine.
  • Page 11 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Tighten caps of large and small view holes, respectively. Install upper cover of cylinder head, and check the engine for leakage. - 11 -...

  • Page 12: Oil Level Inspection

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 2.6 . Oil level inspection 2.6.1 Check engine oil before driving every day. 2.6.2 Oil level must be between the upper and lower lines of the oil level gauge. 2.6.3 Start the engine and let it idle for 3-5minutes.

  • Page 13: Oil Change

    2.7.5 Install the new oil filter with the “DL” mark facing out. Note Use only the UM genuine oil filter or a filter of equivalent quality specified for your model. - 13 -...
  • Page 14 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC using the wrong UM filter or a non-UM filter which is not of equivalent quality may cause engine damage. 2.7.6 Install locating pin. Fix a new sealing washer on the filter cover, then install the cover on the right cover.
  • Page 15 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC LUBRICATION SYSTEM 3.1 Lubrication system (schematic diagram) ..................- 16 - 3.2 Lubrication system (technical specifications) ................... - 17 - 3.3 Troubleshooting: ..........................- 17 - 3.4 Oil pump (extraction and installation) ..................... - 18 - - 15 -...

  • Page 16: Lubrication System (Schematic Diagram)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.1 Lubrication system (schematic diagram) - 16 -...

  • Page 17: Lubrication System (Technical Specifications)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.2 Lubrication system (technical specifications) Unit: mm Item Standard Service Limit Specification SJ 10W/40 when filter is not removed Engine oil Capacity when filter is removed 1.1L when engine is completely dry 1.2L Backlash between outer rotor and pump body 0.28...

  • Page 18: Oil Pump (Extraction And Installation)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.4 Oil pump (extraction and installation) 3 .4.1. Oil pump dismantle 3.4.1.1 Dismantle right cover (refer to 6.5 section), then remove circlip and take out gears of oil pump. 3.4.1.2 Take out the pin and remove fastening bolt of oil pump.
  • Page 19 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.4.2.2. Remove the inner rotor, pin and pin shaft from oil pump. 3.4.2.3. Take out outer rotor of oil pump and clean the components disassembled thoroughly. 3.4.3. Check of oil pump Note: When checking oil pump, turn the rotor to measure it at multiple points, so as judge it if its wear is beyond service limit.
  • Page 20 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.4.3.2. Check fit clearance between outer and inner rotors of oil pump; Service limit 0.20mm 3.4.3.3. Take out the shaft and pin from the oil pump; Use knife straight edge and feeler gauge to measure axial clearance between rotor and casing of the oil pump.
  • Page 21 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.4.4.1. Apply lube oil on the circumference of outer rotor and install the rotor into oil pump casing. 3.4.4.2. Apply lube oil on the circumference of inner rotor, pin shaft and pin and install them into oil pump casing.
  • Page 22 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 3.4.4.5. Assemble oil pump and tighten the bolt. Assemble the pin. 3.4.4.6. Install oil pump gears onto pin shaft and install circlip. Apply an appropriate amount of lube oil on the gears. 3.4.4.7.
  • Page 23 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC CYLINDER HEAD PARTS MAINTENANCE 4.1. CYLINDER HEAD EXPLODED VIEW ....................- 24 - 4.2. UPPER COVER OF CYLINDER HEAD MAINTENANCE ................ - 25 - 4.3. ROCKER ARM SET MAINTENANCE ....................- 27 - 4.4.

  • Page 24: Cylinder Head Exploded View

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.1 Cylinder Head exploded view - 24 -...

  • Page 25: Upper Cover Of Cylinder Head Maintenance

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.2 Upper cover of cylinder head maintenance 4.2.1 Remove two bolts form upper cover of cylinder head 4.2.2 Take out upper cover and corresponding seal gasket 4.2.3 Positioning pin and O-ring for removing the oil path 4.2.4 Remove the washer and screw from upper cover of the cylinder head.
  • Page 26 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.2.5 Detecting oil passage and clean it using air gun 4.2.6 Assemble bolts and washers after the head cover is checked (Need to be replaced old washer by a new one) 4.2.7 Assembly location pin and a new O-ring 4.2.8 Clean the sealing ring groove and mount a new cover sealing gasket, after that, assemble to the cylinder head together.

  • Page 27: Rocker Arm Set Maintenance

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.2.9 After confirming that the upper cover is installed at right place, install rubber gasket of bolt of cylinder head (with mark UP upwards). 4.2.10 Assembling head cap upper cover bolts and tighten.
  • Page 28 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.1.3. Remove the fastening bolts from timing sprocket chain. 4.3.1.4、Remove the timing sprocket chain, Care shall be taken when using a tool to fix the chain to avoid dropping it into the crankcase. - 28 -...
  • Page 29 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.1.5. Remove AB Nut, to take out the ROCKER ARM 4.3.1.6. Loosen fastening bolt on stop plate and remove the stop plate. Then remove camshaft. 4.3.1.7. Remove fastening bolt of rocker arm shaft 4.3.1.8.
  • Page 30 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.1.9. Check bearing at both ends of camshaft for free rotation. 4.3.1.10 、 Inspect the cam for abrasion 4.3.1.11. And check rocker arm shaft for wear heck rocker arm shaft hole for wear, check if 4.3.1.12.
  • Page 31 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Installation rocker arm set 4.3.2. 4.3.2.1. Apply the right amount of lube oil on Rocker shaft hole, roller and rocker arm shaft before installing them 4.3.2.2. Assemble rocker arm and rocker shaft in accordance with sequence shown in the illustration 4.3.2.3.
  • Page 32 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.2.5. Before installing camshaft, apply appropriate amount of lube oil on the circumference of bearings (at both ends). Then apply appropriate amount of SO grease into cams. 4.3.2.6. Mounting the camshaft into the rocker bracket, take special attention to the projected point on flange shall be upward, as shown in the figure.
  • Page 33 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.2.9. Apply appropriate amount of lube oil onto both sides of gasket and external surface of nut, then install them into rocker arm bracket. 4.3.2.10. Tighten AB bolt nut in turn Fastening torque: 3N • m 4.3.2.11.

  • Page 34: Cylinder Head Set Maintenance

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.3.2.13. Assembling fastening Bolts Fastening torque: 9N • m 4.3.2.14. Loosen tensioner device, to check if chain is tensioned 4.3.2.15. Replace O-ring with a new one and assemble the tensioning screw. 4.4 Cylinder head set maintenance 4.4.1 Disassembly of cylinder head 4.4.1.1.
  • Page 35 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.4.1.2. remove the cylinder head assembly 4.4.1.3. Remove the cylinder head seal gasket and the two position pins 4.4.1.4. Use special tooling to dismantle valve collet seat ring, valve, valve steam seal and valve spring respectively.
  • Page 36 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.4.2. Check of cylinder head assembly 4.4.2.1. Check the cylinder Head combustion chamber, clean the carbon deposit; 4.4.2.2. Check valve spring for free length. In: 38.5 – 39.5 mm Outer: 41.5 – 42.5 mm 4.4.2.3.
  • Page 37 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC - 37 -...
  • Page 38 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.4.3. Assembly of Cylinder head set Cylinder head exploded view 4.4.3.1. Assemble the components according to the order of exploded view. 4.4.3.2. When installing valve spring, care shall be taken that the spring dense coil end shall be directed downwards.
  • Page 39 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.4.3.3. The completed cylinder head assembly shall be subject to air tightness test. Next operation shall not be done unless the cylinder head assembly is confirmed air-tight. 4.4.3.4. Assembly positioning pins and a new cylinder head sealing gasket.

  • Page 40: Tensioner Device (Extraction And Installation)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.5 . Tensioner device (extraction and installation) 4.5.1. Remove the screw of the tensioning device 4.5.2. Use the right tools to adjust the tensioning device until loosen position. - 40 -...
  • Page 41 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 4.5.3. Assembly of Tensioner device 4.5.4. Replace O ring with a new one 4.5.5. Tighten the screw - 41 -...
  • Page 42 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC CYLINDER BLOCK AND PISTON 5.1. CYLINDER BLOCK/PISTON EXPLODED VIEW- ................- 43 - 5.2. LIMITS FOR SERVICE ........................- 44 - 5.3. TROUBLESHOOTING ........................- 44 - 5.4. CYLINDER BLOCK – PISTON (DISASSEMBLY AND INSPECTION ) ............- 45 - - 42 -...

  • Page 43: Cylinder Block/Piston Exploded View

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.1 Cylinder block/piston exploded view - 43 -...

  • Page 44: Limits For Service

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.2 Limits for service Cylinder and Piston unit：mm Item Standard value Service Limit Inner diameter of cylinder Φ52.400～φ52.410 Φ52.5 Cylindricity 0.004 0.10 Cylinder Flatness of cylinder face 0.03 0.10 Outer diameter of piston Φ52.38～φ52.39 Φ52.3 Inner diameter of piston pin hole...

  • Page 45: Cylinder Block - Piston (Disassembly And Inspection )

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.4 Cylinder block - piston (disassembly and installation) 5.4.1 Disassembly and inspection of cylinder block 5.4.1.1. Dismantle cylinder head (refer to 4.2 section). Remove the guide plate 5.4.1.2. Knock cylinder block slightly with rubber hammer to separate cylinder block from crankcase.
  • Page 46 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.4.2. Check cylinder block 5.4.2.1. Check diameter of cylinder bore. When doing this task, measure the diameter at three layers respectively, i.e. top, middle and bottom of piston stroke, and measurement shall be taken at two directions mutually perpendicular at every layer.
  • Page 47 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.4.3. Piston disassembly 5.4.3.1. Place a clean cloth under the piston to guard against that circlip of piston pin falls into crankcase during removal. 5.4.3.2. Use long-nose pliers to remove circlip of piston pin.
  • Page 48 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.4.4. Check piston 5.4.4.1. Check piston for damage or break. Check diameter of skirt at 8mm height. Limit value Φ52.3mm 5.4.4.2. After measure diameters of cylinder bore and piston skirt, calculate their fit clearance . Limit value 0.09mm 5.4.4.3.
  • Page 49 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 5.4.4.8. Check gap of piston ring. Install piston ring into cylinder block, and press them down with piston. Check gap of each piston ring with feeler gauge. Top ring 0.40mm Limit value Second ring 0.40mm Oil ring...
  • Page 50 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Note: • Do not damage piston and piston rings during assembling. • Check if piston ring can rotate freely on the piston without any seizure after rings are assembled. • After piston rings are assembled, the splits of piston rings must be placed away from each to other by 120°...
  • Page 51 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Note Do not damage piston surface and cylinder block. 5.4.5. 1. Assembly piston When assembling piston, direct face with mark IN towards intake side. Then assemble piston pin. Apply appropriate amount of lube oil on piston pin, piston pin hole, piston skirt before assembling.
  • Page 52 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Install guide plate of chain into cylinder block Note: Guide plate shall be installed to its place as shown in the figure; otherwise, the plate may be damaged abnormally. Assemble cylinder head and tensioner. (refer to 4.4 section).
  • Page 53 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC RIGHT COVER / CLUTCH / BALANCING GEAR / GEARSHIFT 6.1. EXPLODED VIEW OF RIGHT COVER/ CLUTCH/ BALANCED GEAR/ GEARSHIFT ......- 54 - 6.2. CLUTCH (TECHNICAL SPECIFICATIONS) ..................- 55 - 6.3. TIGHTENING TORQUE REQUIREMENTS ................... - 55 - 6.4.

  • Page 54: Exploded View Of Right Cover/ Clutch/ Balanced Gear/ Gearshift

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.1. Exploded view of right cover/ clutch/ balancing gear/ gearshift - 54 -...

  • Page 55: Clutch (Technical Specifications)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.2. Clutch (technical specifications) Clutch Unit： mm Item Standard Value Service Limit 41.1-41.9 Clutch Spring Free Length 2.92-3.08 Friction Plate Thickness Clutch Flatness of clutch driven plate 0.20 φ23.08 Driven gear inner hole diameter Φ23.000～φ23.021 Φ22.93 Collar diameter...

  • Page 56: Right Cover -Extraction And Installation

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5. Right cover -extraction and installation- 6.5.1. First drain off oil from engine and water from radiator; remove connecting water pipes from right cover and remove bolts from right cover. 6.5.2. Remove the paper gasket and positioning 6.5.3.
  • Page 57 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.4.3. Water pump dismantle impeller 6.5.4.4. Dismantle packing and water pump shaft. 6.5.4.5. Use special tools dismantle mechanical seal assembly, bearing, and take out water seal - 57 -...
  • Page 58 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.4.6. Take out pushing rod of clutch. 6.5.4.7. Use tools to dismantle cotter pin on control arm and take out the spring. 6.5.4.8. Take out clutch control arm and oil seal. 6.5.4.9. Check clutch control deformation;...
  • Page 59 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.5. Partial assembly of right cover 6.5.5.1. Replace oil seal of control arm with new one. Apply appropriate amount of lube oil onto lever of control arm, then install the arm into right cover. 6.5.5.2.
  • Page 60 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.5.4. Cooling system assembly 6.5.5.4.1. Cooling system exploded view 6.5.5.4.2. Cleaning 6.5.5.4.3. Assemble 2 bearings (6001) and water pump shaft. - 60 -...
  • Page 61 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.5.4.4. Assemble oil seal of water pump shaft 6.5.5.4.5. Install mechanical seal assembly. 6.5.5.4.6. Assemble impeller packing of water pump. 6.5.5.4.7. Assemble impeller of water pump. - 61 -...
  • Page 62 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.5.6. Assembly location pins and new paper gasket. 6.5.6.1. Removal of clutch gasket and engine oil from crankcase before assembling 6.5.7. Assemble right cover, bracket, bolts. (First, tighten the bolt at locating pin, then tighten other bolts alternatively) Note: When assemble right cover, rotate impeller of water pump so checked water pump shaft is aligned...

  • Page 63: Clutch (Extraction And Installation)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.6. Clutch (extraction and installation) 6.6.1. Clutch extraction. 6.6.1.1. Dismantle 4 bolts from end cover of clutch, then take out end cover of clutch, bearing, declutch spring. 6.6.1.2. Dismantle locknut and washer of clutch 6.6.1.3.
  • Page 64 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.6.1.5. Take out declutch shaft sleeve 6.6.2. Check of clutch 6.6.2.1. Check bearing of clutch for free rotation. 6.6.2.2. Check declutch spring of clutch for damage. Measure free length of spring. Service limit 39.6mm 6.6.2.3.
  • Page 65 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.6.2.4. Check if drive friction plates discolors, measure thickness of drive friction plate. Service limit 2.6mm 6.6.2.5. Check driven friction plates flatness. Service limit 0.20mm 6.6.2.6. Check outer case of clutch and shaft sleeve abnormal geometry.
  • Page 66 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.6.3. Clutch assembly 6.6.3.1. Apply appropriate amount of engine oil onto internal and external surface of shaft sleeve, then assemble declutch shaft sleeve onto main shaft 6.6.3.2. Apply appropriate amount of lube oil onto gears.

  • Page 67: Gearshift Arm (Extraction Installation)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.6.3.5. Assemble gaskets and nuts. Apply appropriate amount of engine oil onto end face of nut 6.6.3.6. Use tools to fix pressure plate and tighten locknut of clutch. Tightening torque shall meet specified requirement Tightening torque: 74N.m...
  • Page 68 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.7.2. Remove bolt of star-shaped plate, then dismantle the plate 6.7.3. Dismantle components and parts in order: • • Locating plate • Locating plate bolt • Locating plate spring • Washer 6.7.4. Check of gearshift arm.
  • Page 69 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.7.6. After displace locating plate with flat screwdriver, assemble pin and star-shaped plate. Pin holes on the star-shaped plate shall be aligned with two cylindrical pins. 6.7.7. Tighten bolt on star shaped plate Tightening torque 12 N.m.

  • Page 70: Drive Gear - Balancing Gearshift Arm (Extraction And Installation)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.8. Drive gear – balancing gearshift arm (extraction and installation) 6.8.1. Balancing drive gear extraction 6.8.1.1. Dismantle locknut and washer of drive gear 6.8.1.2. Take out drive gear. 6.8.1.3. Take out balancing gear Note Do not damage woodruff and circumference of crankshaft when...
  • Page 71 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.8.2.4. Align keyway on drive gear with woodruff key on crankshaft and assemble them. Apply appropriate amount of engine oil on gears. 6.8.2.5. Assemble washer, locknut of drive gear. 6.8.2.6. Tighten nut to specified torque; Tightening torque: 64N.m 6.8.3.
  • Page 72 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.8.3.2. Take out shaft sleeve and woodruff key. 6.8.3.3. Balancing driven Gear (Disassembly and assembly). 6.8.3.3.1. Dismantle circlip, washer, disc washer, flat washer in turn; 6.8.3.3.2. Take out balancing driven gear, two springs, two buffer rubber bushing 6.8.3.3.3.
  • Page 73 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 6.8.4. Assembly of driven gear of balancing shaft 6.8.4.1. Assemble shaft sleeve and woodruff key onto balancing shaft Note Do not damage circumference balancing shaft and keyway 6.8.4.2. Align keyway of balancing driven gear with woodruff key on balancing shaft.
  • Page 74 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7. LEFT COVER / STARTING MOTOR SYSTEM / MAGNETO 7.1. EXPLODED VIEW OF LEFT COVER/ STARTING MOTOR SYSTEM/ MAGNETO ......- 75 - 7.2. LEFT COVER (EXTRACTION AND INSTALLATION) ..............- 76 - 7.3.
  • Page 75 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.1. Exploded view of left cover/ starting motor system/ magneto - 75 -...
  • Page 76 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.2. Left cover (Extraction and installation) 7.2.1. Take out gearshift switch harness from harness groove. 7.2.2. Loosen fastening bolt on left cover and remove left cover 7.2.3. Take out locating pin and paper gasket. Assemble locating pin and new paper gasket.
  • Page 77 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.2.5. Insert gearshift switch harness into harness groove on left cover 7.3. Starting motor system (extraction and installation) 7.3.1. Dismantle left cover and take out shaft sleeve, dual gear shaft and dual gear 7.3.2.
  • Page 78 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.3.4. Dismantle locknut on magneto. Use special tools to dismantle magneto rotor 7.3.5. Check needle bearing, woodruff key on crankshaft for damage 7.3.6. Clean off engine oil from tapered face of crankshaft. Install magneto rotor and turning the gear on crankshaft, thus align keyway with woodruff key 7.3.7.
  • Page 79 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.3.8. Use tools to fix magneto and tighten nut to specified torque. Tightening torque: 74 N.m. 7.3.9. Replace O-ring with a new one. Apply appropriate amount of lube oil onto O-ring before assembling. 7.3.10.
  • Page 80 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.3.12. Starting motor system check. Assemble large starting gear onto magneto rotor, then check if the gear can rotate normally, making rotate counterclockwise 7.3.13. Magneto rotor disassembly. 7.3.13.1. Use special tools to fix rotor, then dismantle rotor bolts.
  • Page 81 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.3.13.4. Check teeth of large starting gear for damage Measure outer diameter of large starting gear Service limit 45.60mm 7.3.13.5. Magneto rotor exploded view - 81 -...
  • Page 82 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.3.13.6. Assemble overrunning clutch 7.3.13.7. Install overrunning clutch onto magneto rotor, and align through hole with threaded hole 7.3.13.8. Apply appropriate amount fastening adhesive onto threads of bolts, then use tools to locate and tighten the bolt Tightening torque: 16 N.m.
  • Page 83 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 7.4. Magneto stator (extraction and installation) 7.4.1. Remove rubber plug, magneto cable clip and sensor 7.4.2. Dismantle fastening bolts on stator and take out magneto 7.4.3. Install a magneto onto left cover, then tighten bolts 7.4.4.
  • Page 84 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8. CRANKCASE (EXTRACTION AND INSTALLATION) 8.1. CRANKSHAFT (EXPLODED VIEW) ..................... - 85 - 8.2. TECHNICAL SPECIFICATIONS ...................... - 86 - 8.3. CRANKSHAFT EXTRACTION ...................... - 87 - 8.4. DRIVE TRAIN (EXTRACTION AND CHECK) ................... - 89 - 8.5.
  • Page 85 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.1. Crankcase (exploded view) - 85 -...

  • Page 86: Crankshaft (Exploded View)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.2. Technical specifications unit: mm Item Standard Service Limit Connecting Rod Radial Clearance 0~0.008 0.03 Crankshaft, Connecting Large End: Side Clearance 0.1~0.35 Rods Crankshaft Runout 0.03 0.08 Fork Outer diameter Φ9.966~φ9.984 Φ9.93 Fork Fork Inner diameter Φ10.000~φ10.018...

  • Page 87: Crankshaft Extraction

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.3. Crankshaft extraction 8.3.1. Dismantle corresponding components and parts (cylinder head, cylinder block, right cover, left cover) in accordance with steps described above. 8.3.2. Loosen and dismantle fastening bolt on chain guard, then take out chain guard, tension plate, guide plate and chain 8.3.3.
  • Page 88 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.3.6. Dismantle fastening bolt right crankshaft 8.3.7. Dismantle fastening bolts on crankshaft 8.3.8. Place crankcase properly with right half downwards. Knock counter shaft and crankshaft with rubber hammer to loosen adhesive on halves (left and right). Place horizontally the crankcase and remove left half upwards 8.3.9.

  • Page 89: Drive Train (Extraction And Check)

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.3.10. Check chain tension plate for severe wear or damage. If there is, replace the tension plate with a new one 8.4. Drive train (extraction and check) 8.4.1. Take out fork shaft of main and counter shafts 8.4.2.
  • Page 90 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.4.4. Check main and counter shafts 8.4.4.1. Disassemble gears on main and counter shafts. 8.4.4.2. Check gears for severe wear or damage. Check inner diameter of the gears Φ20.04mm Φ20.04mm Service Φ20.55mm limit Φ23.07mm Φ23.07mm...
  • Page 91 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC Check spline key and main and counter shaft for abnormal wear and damage Measure diameter shaft gear-matching position. Service limit φ16.93mm of outer φ16.93mm diameter of φ19.94mm main and counter φ19.95mm shafts Calculate fit clearance between gears and shaft sleeve Service limit...

  • Page 92: Bearings Extraction

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.4.5.3. Check fork shaft for abnormal wear and damage. 8.4.6. Replacement of bearings 8.4.6.1. Turn inner race of bearing to check if it can rotate freely 8.4.6.2. Check bearing cage and balls, looking for severe wear and damage 8.5.
  • Page 93 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.5.3. Dismantle counter shaft and gearshift arm oil seals, located on left half. 8.5.4. Dismantle bearings from left half using a bearing puller tool - 93 -...

  • Page 94: Bearings Installation

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.6. Bearing installation 8.6.1. Apply appropriate amount of engine oil on outer race bearing, then press the bearings into corresponding holes with special tools Note Bearing shall be installed using special tools. When pressing bearing, force shall be applied on outer race of bearing;...

  • Page 95: Drive Train Assembly

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.7. Drive train assembly Clean the components and parts with 8.7.1. cleaning agent Dry the cleaned components and parts 8.7.2. using air, then apply engine oil on it. Apply appropriate amount of grease onto 8.7.3.
  • Page 96 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.7.5. Main shaft (Exploded view) 8.7.6. Counter shaft (exploded view) - 96 -...
  • Page 97 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.7.7. Apply appropriate amount of lube oil onto fork groove and gears 8.7.8. Install main and counter shafts into right half of crankcase. Care shall be taken to not miss washers at both ends of the shafts 8.7.9.

  • Page 98: Crankshaft Check

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.7.11. Apply appropriate amount of engine oil onto fork shaft and insert the shaft into fork hole. Rotate counter shaft check if all components and parts are installed in the right positions, and main and counter shafts can rotate freely 8.8.
  • Page 99 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.8.4. Measure side clearance between large-end of connecting rod and crankpin using feeler gauge Service limit 0.5mm 8.8.5. Measure connecting rod radial clearance, at the large end Service limit 0.05mm Check timing drive sprocket on crankshaft for abnormal wear and damage.

  • Page 100: Crankcase Installation

    UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.9. Crankcase installation 8.9.1. Install crankshaft into right half of crankcase 8.9.2. Install balanced shaft. 8.9.3. Clean matching faces on left and right halves of crankcase. Apply sealing adhesive on matching face of left half as shown in the figure 8.9.4.
  • Page 101 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.9.5. Assemble left half of crankcase onto right half. Note When installing left half of crankcase, if it is found that the two halves cannot bind closely together, check if the components inside the halves are installed onto their positions, and if there are foreign elements in the crankcase.
  • Page 102 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 8.9.9. Install pressing pin body and pressing pin body spring. Note Tapered face of pressing pin body shall contact bearing. 8.9.10. Apply adhesive to thread on 2/3 of length, then install pressing pin body guard and bolts onto crankshaft case.
  • Page 103 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 9. EFI DIAGNOSTIC SYSTEM RENEGADE II 125 SERIES EFI 9.1. GENERAL INFORMATION ....................... - 104 - 9.2. STEPS TO MAKE THE DIAGNOSTIC ..................- 104 - 9.3. OBD II STANDARD FAULT CODES .................... - 109 - - 103 -...
  • Page 104 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 9.1. General information The UM motorcycles “Renegade II 125 series EFI” have a “Mikuni” EFI system with the following components: • ECU (Engine Control Unit) • Electric fuel pump • Throttle position sensor •...
  • Page 105 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC main screen when the app has been installed successfully. Note: To installation of Android version, Searching iOBD2 on Google play, download the app and install. 9.2.2. Installation to OBD II port Plug the iOBD2 adapter into the OBD II port on the motorcycle and turn the ignition switch on without starting the engine.
  • Page 106 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC • Wait for “Connection Successful” logo to appear Note: With the XTOOL adapter you can only use some of Diagnostic and Dashboard options. 9.2.4. Trouble codes • You can use “Diagnostic” to scan and read all failure codes (Trouble Code).
  • Page 107 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC P0628 FUEL PUMP FAILURE P2300 IGNITION COIL LOW VOLTAGE CIRCUIT FAILURE Note Please refer to 9.3 section to see the complete list of all standard OBD2 failure codes 9.2.5. Erasing trouble codes If a trouble code was solved and need to be erased press the “Clear Trouble Code”...
  • Page 108 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 9.2.6. Live data In Diagnostic you can use “Live Data” to read in real time some of the sensors of the system. The picture below shown: A. All the sensors to read, Press “Done” B.
  • Page 109 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC 9.3. OBD II standard fault codes P0115 Engine Coolant Temperature Circuit Malfunction P0116 Engine Coolant Temperature Circuit Range/Performance Problem P0117 Engine Coolant Temperature Circuit Low Input P0118 Engine Coolant Temperature Circuit High Input P0119 Engine Coolant Temperature Circuit Intermittent P0120 Throttle Pedal Position Sensor/Switch A Circuit Malfunction P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem...
  • Page 110 UXPW 125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC P0562 System Voltage Low P0563 System Voltage High P06XX Computer and Auxiliary Outputs P0600 Serial Communication Link Malfunction P0601 Internal Control Module Memory Check Sum Error P0602 Control Module Programming Error P0603 Internal Control Module Keep Alive Memory (KAM) Error P0604 Internal Control Module Random Access Memory (RAM) Error P0605 Internal Control Module Read Only Memory (ROM) Error (Module Identification Defined by SAE J1979) P0606 PCM Processor Fault...

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