KEEWAY 50cc Series Service Manual
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KEEWAY 50cc Series Service Manual

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SCOOTER SERVICE MANUAL
KEEWAY 50cc Models
© KEEWAY AMERICA, LLC
SPRING 2008

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  • Page 1 SCOOTER SERVICE MANUAL KEEWAY 50cc Models © KEEWAY AMERICA, LLC SPRING 2008...
  • Page 2 If problems cannot be resolved or further assistance is needed, please feel free to contact us. KEEWAY AMERICA, LLC 2912 SKYWAY CIRCLE N. IRVING, TX 75038 214-441-9661 PHONE 214-441-9641 FAX service@keeway-america.com Our support staff will assist in any way possible.
  • Page 3 PRE-DELIVERY INSPECTION In order for KEEWAY America to maintain its high standards of quality, it is necessary for each dealer to thoroughly inspect each unit before their customer takes delivery. INITIAL: Wash entire vehicle with warm water and wipe dry with a soft cloth. DO NOT USE SOAP OR TERRY CLOTH.
  • Page 4 TEST DRIVE: Verify proper front and rear suspension for correct damping and travel. Ensure proper operation and settings of gauge cluster. Verify wheel alignment, and adjust accordingly. Check for fluid leaks, and adjust levels accordingly. Verify proper operation and adjustment of all vehicle lights. FINAL: Wipe down entire vehicle with soft cloth to remove any dust or debris.
  • Page 5 MAINTENANCE CHART...
  • Page 6 TABLE OF CONTENTS__________________________ PREDELIVERY INSPECTION MAINTENANCE CHART PREFACE KEEWAY SERVICE GUIDELINES ELECTRICAL PRECAUTIONS SAFETY GUIDELINES SPECIALTY TOOLS REQUIRED GENERAL INFORMATION Terminology The 2-Stroke Engine Cycle Vehicle Information General Specifications POWERTRAIN SPECIFICATIONS Fastener Torque DIMENSIONS Alignment Pins/Dowels Pin shafts O-rings Seals...
  • Page 7 ENGINE COMPONENT FIT/TOLERANCE Cylinder Head/Valve Cylinder Jug/Piston SYSTEM FUNDAMENTALS Kick Start Chain Reaction Fuel Delivery System Brake System Fundamentals Fundamental Front Absorber Theory TROUBLESHOOTING AND PROCEDURES COMMON ISSUES Electric Starter Doesn’t Engage or Rotate Only Clicking Noise When Starter Button Is Pressed No Reaction Whatsoever When Starter Button Is Pressed Hard Start/Poor Idle/Poor Performance No Start...
  • Page 8 POWERTRAIN COMPONENTS CARBURETOR REMOVAL/INSTALLATION ENGINE AND COMPONENTS REMOVAL/INSTALLATION Cowling Assembly Cylinder Head Assembly Camshaft/Rocker Arm Assembly Piston Assembly LH Crankcase Cover RH Crankcase Cover, Magneto, and Associated Parts RH Crankcase Internals LH Crankcase Cover and Associated Parts Crankcase Assembly Transmission Case Assembly Drive Wheel Clutch Assembly Kick Start Gear Assembly Transition Gear Assembly...
  • Page 9 Please understand that this service manual acts as a general guide for KEEWAY’s entire line of 50cc, 2-stroke scooters. Model-specific information such as vehicle specifications, wiring diagrams and technical/service bulletins will follow, keeping this guide as complete and current as possible.
  • Page 10 KEEWAY SERVICE GUIDELINES Use only genuine KEEWAY parts, and use proper lubricants where specified. Use only the proper tools for the task at hand. Please be sure to replace all washers, seals, o-rings, cotter pins, etc. Please note that all fasteners are metric.

  • Page 11: Safety Guidelines

    SAFETY GUIDELINES WARNINGS: Use only the appropriate, well-maintained tool for the task at hand. Gasoline is a highly volatile chemical, and should be treated with care. Never handle near open flame or heat source. Keep floor clean and free of debris. Avoid fluid spills to minimize the risk of accidents and equipment damage.
  • Page 12 SPECIALTY TOOLS REQUIRED T-Driver and socket set (8, 10, 12, 13mm, and screwdriver bits needed) Flywheel removal tool Valve spring compressor Spanner socket Cylinder compression tester Piston pin removal tool...
  • Page 13 13/16 Spark plug socket (2 styles shown) Impact wrench Impact sockets (17 & 18mm needed) Clutch clamp tool Torque wrench (and appropriate sockets) Recommend both lbs-ft and lbs-in...

  • Page 14: General Information

    GENERAL INFORMATION_________________________ TERMINOLOGY The two absolute maximums of linear piston travel in the internal combustion engine are referred to as TOP DEAD CENTER (TDC) and BOTTOM DEAD CENTER (BDC). Note that TDC is at the point farthest from the rotation center of the crankshaft, and BDC is the closest point.
  • Page 15 THE 2-STROKE ENGINE CYCLE The 2-stroke engine differs slightly from the 4-stroke, in that it combines its phases, or strokes. Upon initial inspection, the most noticeable difference in overall 2-stroke architecture is the location of the INTAKE PORT. It provides a direct feed into the CRANKCASE, and then moves into the CYLINDER via the TRANSFER PORT.
  • Page 16 Now the piston is reaching TDC, completely compressing the air/fuel mix in the combustion chamber. NOTE: The exhaust and transfer ports are still blocked by the piston skirt; the intake port is still open, but the crankcase has now filled to capacity.
  • Page 17 This is the final, and perhaps most complicated step in the 2-stroke process. As the piston travels downward, the EXHAUST PORT opens. This allows the combusted gasses to exit the engine. As the piston continues downward, the TRANSFER PORT is now exposed. This allows for the compressed mix in the crankcase to expand and enter the cylinder.

  • Page 18: Vehicle Information

    Be sure to only use unleaded fuel, 90 Octane or better. Engine Oil For KEEWAY’s oil injection system, high-quality engine oil is necessary. KEEWAY America recommends full synthetic 2-stroke engine oil with the designation “suitable for 2-stroke oil injection systems”.

  • Page 19: General Specifications

    GENERAL SPECIFICATIONS Chassis Front Shock Absorber Spring, Oil Damped Rear Shock Absorber Spring, Oil Damped Turn Angle 48° (to left/to right) Brakes F/R Disk/Drum Engine Type 2-Stroke, Forced-Air-Cooling Intake Piston-Reed Valve Cylinder Single Bore 40.0mm Stroke 39.6mm Displacement 49.8mL Compression Ratio 6.9:1 Timing 15°...
  • Page 20 POWERTRAIN SPECIFICATIONS________________ FASTENER TORQUE Self-tapping screws for fan cover assembly 1-3Nm (9-26 lbs-in) Locknuts for fan cover assembly 10-12Nm (8-9lbs-ft) Self-tapping screws for air cover 1-3 Nm (9-26 lbs-in) Lock nut for air cover 10-12Nm (8-9lbs-ft) Self-tapping screw and nut for cylinder head cover vent 1-3Nm (9-26lbs-in) Locknut for cylinder head cover 10-12Nm (8-9lbs-ft)
  • Page 21 Locknut for fixed drive assembly 40-60Nm (29-43lbs-ft) Kick starter locknut 10-12Nm (8-9lbs-ft) Transmission case cover locknut 10-12Nm (8-9lbs-ft) Transmission case drain nut 22-25Nm (16-18lbs-ft) LH crankcase drain nut 22-25Nm (16-18lbs-ft) LH crank position shaft nut 18-22Nm (13-16lbs-ft)
  • Page 22 ENGINE COMPONENT FIT/TOLERANCE___________ REED VALVE/ CYLINDER HEAD Reed Valve seat clearance (A): < 0.2mm overlap (B): 1mm Cylinder Head Surface Clearance < 0.05mm CYLINDER/PISTON Compression 155±5psi Cylinder Inner Diameter 40.005-40.020mm Piston Diameter 39.94-39.955mm Piston/Cylinder Tolerance 0.06-0.07mm...
  • Page 23 PISTON PIN Piston Pin Guide 12.01mm Piston Pin 12.00mm Pin/Guide Tolerance 0.01mm PISTON RING Ring/Groove Tolerance first: 0.04-0.06mm second: 0.02-0.04mm Acceptable Ring End-Gap 0.75-3.6mm (uniform) SYSTEM FUNDAMENTALS________________________ KICK START CHAIN REACTION Kick-Start Lever (9) Starting Gear (10) Transitional Gear (11) (through small, on to large) Crankshaft Driven Gear (13) Crankshaft (3)
  • Page 24 FUEL DELIVERY SYSTEM The vehicle’s fuel flows by gravity feed into the petcock valve, where its flow rate is boosted through vacuum assistance, allowing for a steady and potentially constant feed into the carburetor. From the petcock to the carburetor, the fuel undergoes a double-filtration process. First, the fuel flows through a strainer as it enters the petcock, removing any major debris.
  • Page 25 At idle, the fuel is sprayed in a fine mist into the carburetor throat by the idle jet. Since the throttle body is completely closed, air passes through the idle passage and into the throat as well, blending with the fuel mist. This blending process can be adjusted through the IDLE AIR SCREW.

  • Page 26: Lubrication System

    Under a HIGH-speed condition, the throttle body is opened up all the way, allowing maximum airflow. This creates the greatest vacuum pressure possible, resulting in maximum fuel spray from the main jet. The air/fuel mixture becomes richer to facilitate the faster, hotter combustion necessary to support the increased engine speed and demand.
  • Page 27 DISK BRAKE SYSTEM FUNDAMENTALS Hydraulic theory: liquid cannot be compressed, only displaced. Therefore, force can be amplified and carried through fluids by application of force to surface in a sealed system. 1 Cap 8 Plunger 2 Gasket 9 Tension Spring 3 Fluid Journal 10 Fluid Outlet 4 Dust Boot 11 Return Port...
  • Page 28 Caliper Assembly 1 Bleeder Bolt Dust Cover 2 Banjo Bolt 3 Fluid Path 4 Caliper Body 5 Pistons 6 Guide Bolt Sleeves 7 Piston Seals 8 Piston Dust Covers 9 Brake Rotor...
  • Page 29 NOTE: KEEWAY America discourages disassembly of absorbers for the purposes of diagnosing and repairing KEEWAY vehicles. Always replace the absorbers as...
  • Page 30 TROUBLESHOOTING AND PROCEDURES________ IMPORTANT NOTE: before attempting any troubleshooting or repairs, please ensure that scooter is placed on the main stand. COMMON ISSUES The following compilation describes the most common symptoms and potential solutions in the form of a flow chart. Further testing is not needed once the problem has been solved. ELECTRIC STARTER DOESN’T ENGAGE OR ROTATE Verify proper state of battery charge.
  • Page 31 Upon completion of properly tuning the carburetor, replace the vehicle spark plug. If condition continues, verify adequate oil flow and ensure proper spark, then verify proper ENGINE TIMING (refer to guide for proper procedure and specifications) if necessary. If out of range, the MAGNETO ASSEMBLY is most likely sending a faulty reference to the CDI, and needs replacement (refer to guide for removal/installation).
  • Page 32 Vehicle should now start. If hard-start/poor idle condition is now present, refer to appropriate section (above). If no-start condition remains and spark plug is gas-fouled, the carburetor’s enrichment valve needs replacing. From this point, if no-start condition remains, perform an ENGINE COMPRESSION TEST (refer to guide for proper procedure and specifications).
  • Page 33 If the symptom has persisted to this point, KEEWAY recommends disassembly of the cylinder head and inspection for proper lubrication, verification of carbon buildup, and a potentially warped/uneven surface. Inspect the piston assembly and cylinder jug for the same signs.
  • Page 34 The MAGNETO ASSEMBLY most likely has damaged components, and needs replacement (refer to guide for removal/installation). Recommend replacement of CDI as well. POOR/DIFFICULT HANDLING/INSTABILITY If turning is difficult Inspect fork bearings and lubricate/replace as needed. Ensure proper torque is applied to the retaining nut. Wheel wobble or hop Inspect wheel bearing for excessive play.
  • Page 35 SOFT BRAKES OR TOO MUCH LEVER TRAVEL Ensure proper brake fluid level. Inspect both pads and shoes for proper travel and excessive wear. Ensure absence of air in brake lines. Inspect system for leaks. Inspect caliper piston seal for signs of aging/damage. Verify that wear on brake pads and rotor is within limits, with no damage or warping.

  • Page 36: The Battery

    THE BATTERY In order to troubleshoot the battery, the cornerstone of the vehicle’s electrical system, all vehicle systems must be off. Turn voltmeter to DC VOLTS. With the alarm disarmed, connect the test leads from the digital multimeter to the battery posts, red to positive and black to negative (alligator clips ideal).
  • Page 37 POWER CIRCUITRY AND PARASITIC DRAW TEST GUIDELINES The parasitic draw test is a procedure used to pinpoint the source of severe voltage draws in electrical systems due to a short in the circuitry. Specific Tool Required: Digital Multimeter PARASITIC DRAW TEST PROCEDURE: Before beginning, ensure that electrical system is entirely disabled by verifying that ignition cylinder is in OFF position and keys removed, and that the vehicle kill switch is in the NO RUN position.
  • Page 38 IMPORTANT NOTE: In vehicles with theft-deterrent/remote-start systems, unplugging the alarm box will result in an amperage drop. THIS DOES NOT NECESSARILY DENOTE A FAULTY ALARM SYSTEM. The entire vehicle is powered through the alarm box.
  • Page 39 200±20 at 20º C (68º F) Stator <2 Blue (2) NOTE: Testing for all resistance is verified on ground side of circuit. There is no capacitor in the stator assembly. KEEWAY America encourages replacement of the entire magneto assembly when any component is faulty.
  • Page 40 ENGINE COMPRESSION TEST Procedure NOTE: Perform initially on cold engine, then bring engine to operating temperature and repeat. Compare results. Disable ignition (via the vehicle kill switch), remove the spark plug, and connect compression tester. REQUIRES SPECIAL TOOL T05 Disconnect vacuum line from fuel petcock valve. Open Throttle completely and crank for 6-8 revolutions.
  • Page 41 If engine compression is below specifications, repeat test procedure, placing several drops of oil into combustion chamber JUST BEFORE connecting compression gauge. If the compression rises to within range, there is excessive wear or damage to the cylinder, piston, rings, or cylinder head/gasket. Ensure proper valve timing and seat Ensure proper cylinder head gasket seat and seal, and proper torque applied to head bolts.
  • Page 42 IGNITION TIMING TEST Procedure Remove inspection cap from fan cover. Connect timing light according to manufacturer-specific directions Start engine and aim timing light at the timing reference. At idle: I and F marks should line up. This denotes ignition timing of 13º BTDC. Idle speed should be approx.
  • Page 43 12.5-12.8 volts at the battery. Technical Guide for Keeway 50cc Carburetors Keeway America uses two primary forms of carburetors. A mechanical slide type is used on the 50cc units, and a constant velocity (CV) style is used on the 150cc four- stroke units.
  • Page 44 The 50cc carb also has an “automatic enrichment valve” mounted on the right side. This valve feeds both fuel and air to the engine side of carb slide. It is designed to maintain stochiometric metering, admitting both fuel and air. This valve is an electronic solenoid that moves in or out based on a signal from the stator or the CDI.
  • Page 45 IMPORTANT NOTE: When adjusting the idle air mixture screw to baseline settings DO NOT tighten screw after it “seats”. If the air mixture screw is over tightened one of two things will occur; the tapered needle will mushroom and not function, or the needle will break off in the carb body, ruining the slow circuit.
  • Page 46 POWERTRAIN COMPONENTS___________________ CARBURETOR REMOVAL/INSTALLATION Removal Remove seat/helmet box assembly. Remove fuel inlet line Loosen the clamp between carburetor and air box and remove intake duct. Remove plug from fuel overflow/discharge hose and drain any remaining fuel into a safe container. Disconnect enrichment valve pigtail.
  • Page 47 ENGINE COMPONENTS REMOVAL AND INSTALLATION CYLINDER/HEAD ASSEMBLY Removal (remove cowling prior) Cylinder jug and assoc. gasket (4 & 5) Spark plug and cylinder head nuts (3 & Installation procedure is opposite of removal. Cylinder head and assoc. gasket (1 & 2)
  • Page 48 PISTON ASSEMBLY Ring End Gap: 0.25mm (0.010in) minimum Service limit: 0.75mm (0.030in) Ring/Groove Tolerance First: 0.04-0.06mm (0.0015- 0.002in) Second: 0.02-0.04mm (0.001- 0.0015in) Removal (remove cowling, cylinder head assembly and cylinder jug prior) First and second rings (1 & 2) Installation procedure is reverse of removal;...
  • Page 49 LH CRANKCASE COVER Removal Cable clip and fender bracket (1 & 2) LH Crankcase cover (3) Dowel and gasket (4 & 5) Installation procedure is opposite removal. NOTE: after ensuring proper alignment, installation may be facilitated by gently tapping cover into position with a rubber mallet. Upon starting all bolts, proceed to apply torque in a modified star pattern, bringing them all to 8-9lbs-ft.
  • Page 50 LH CRANKCASE COVER AND ASSOCIATED PARTS Removal Nut, star washer, and fixed face Spring retainer and kick-start gear (6, 7, & (10 & Drive Belt, nut, and washer Crankshaft starter and transition gears (16, 15, & 14) & 9) Spacer and variator assembly (4 &...
  • Page 51 reference aligned with contact point at transition gear. A brake spring tool is recommended for applying tension to kick start spring; USE CAUTION. Immediately install retaining plate and lock bolt. Install drive belt before installing fixed face. CRANKCASE ASSEMBLY Removal (remove cylinder Installation head,cylinder jug, and piston assembly LH Crankcase assembly (8)
  • Page 52 NOTES: When installing crankshaft assembly, coat LH crankcase bearing with oil, then vertically press oil seal into bearing recess; place crankshaft gear into camshaft timing chain; ensure free movement of crankshaft and connecting rod assembly. A rubber mallet may be needed to gently tap the crankcases together. Ensure free movement of crankshaft and connecting rod assembly after assembling the crankcase assembly.
  • Page 53 NOTES: Position each bearing with number facing outward, and ensure free movement. Lightly coat oil seal with oil when installing, and ensure proper direction and fit. Ensure proper fit and free movement of all gears and pinions. Torque bolts in modified star pattern to 8lbs-ft.
  • Page 54 Rear seat (6) Installation procedure is opposite of removal. NOTES: When assembling clutch shoe assembly, be sure to use new limiters and pins, to ensure proper fit and function. When installing bearings, coat with assembly lube to ensure free rotation, and ensure proper positioning of the clip. KICK START SHAFT ASSEMBLY Removal Kick start shaft assembly...
  • Page 55 NOTES: Coat bushings and shaft ends with grease to ensure proper installation, and ensure proper spring pin installation. TRANSITION GEAR ASSEMBLY Removal Transition gear assembly Pin (6) Washer (4) Transition gear (3) with bracket (5) intact Tension spring (2) Transition gear shaft (1) Bracket (5) Installation procedure is reverse of removal.
  • Page 56 NOTES: Install bracket in proper groove before installing transition gear. Ensure proper movement of transition gear.
  • Page 57 VARIATOR/CVT ASSEMBLY Removal Fixed face (1) Rollers (6) Spacer (2) Bushing (3) Retaining face (8) Thrust Washer (4) Dampers (7) Movable face (5) Installation procedure is reverse of removal. NOTES: Before installing retaining face, install dampers. Ensure free movement of the spacer.
  • Page 58 STARTER CLUTCH ASSEMBLY Removal Clutch gear (1) Rollers, spring and bushing (6, 7, & 8) Needle bearing (2) Clutch cover (9) M6 Screws (3) Spring retainer (10) Clutch hub (4) Clutch body (11) Pin (5) Installation procedure is reverse of removal. NOTES: There should be no play in clutch assembly.

  • Page 59: Torque Specifications

    CHASSIS_______________________________________ TORQUE SPECIFICATIONS Front Wheel/Fork Axle Nut (1) 41-44lbs-ft Fork Legs to Triple Clamp (4) 27-32lbs-ft Brake Assembly Mount (2) 16-21lbs-ft Handlebar Handlebar to Triple Clamp (1) 27-32lbs-ft Frame Engine Bracket Mount (1) 28-32lbs-ft Rear Shock to Frame (1) 28-32lbs-ft Rear Wheel/Rear Shock Axle Nut (1) 73-95lbs-ft...
  • Page 60 COMPONENT GUIDE FRONT WHEEL ASSEMBLY Removal Axle locknut (17) Seal, bearings, and axle shaft bushing (5, 6, & 18) Axle (3) Tire (16) LH Bushing and speedometer gear assembly (4 & 8) Valve stem and cap (2 & 20) Front wheel assembly Installation procedure is reverse of removal.
  • Page 61 REAR WHEEL ASSEMBLY Removal Locknut Brake shoes and springs (1 & 2) Tension spring and bushing (3 & 4) Rear wheel assembly M6x35 Bolt (9) Tire (8) Brake rocker arm (5) Valve stem and cap (11 & 12) Brake cam (6) Rear wheel (7) Installation procedure is reverse of removal.
  • Page 62 EXHAUST ASSEMBLY Removal Bolts and flange gasket (8 & 9) Expansion chamber stabilizer bolts, washers, and grommets (11, 12, & 13) Exhaust assembly (1) Muffler strap, insulator, and associated bolt (4, 6, & 10) Muffler mounting nuts and gasket (5 & 15) Installation procedure is reverse of removal (assemble exhaust assembly prior) NOTE: Apply red thread locker to muffler studs before installing mounting bolts to ensure vibration resistance.
  • Page 63 FRONT FORK ASSEMBLY Removal M10x1.25x40 Bolts (17) Bring washer and spacer (9 & 10) down onto triple clamp stem. LH and RH shock absorbers (12 & 13) CAREFULLY lower race (8) with a hand Stem locknut and seal (1 & 2) underneath.
  • Page 64 LH and RH shock absorbers (12 & 13) Install M10x1.25x40 bolts (17). NOTE: KEEWAY America discourages disassembly of shock absorber assemblies for the purposes of repairing and reinstalling on KEEWAY units. Always replace the entire assembly, and replace them in pairs.

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