Thumpstar YX Owner's Manual
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Thumpstar YX Owner's Manual

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MANUAL # 3598

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  • Page 1 MANUAL # 3598...
  • Page 2 Owner’s Manual engine manual • 50cc • 88cc fenghong • 70cc • 110cc • 125cc • 140cc • 150cc • 160cc • 180cc Zongshen • 155cc • 190cc...

  • Page 3: Table Of Contents

    Contents These pages give an overview of the contents of your owner’s manual Quick Reference ..................1 Introduction ..................2 Motorcycle Assembly ................3 A Few Words About Safety ..............6 Motorcycle Safety ................. 7 Exhaust System ..............9 Fuel Handling ..............9 Safety Equipment ..............
  • Page 4 Tires & Tubes ..............78 Drive Chain ..............82 Appearance Care ................86 Preparing for a Ride ................88 Transporting your Thumpstar ............89 Storing your Thumpstar ..............90 Troubleshooting ................. 92 You & the Environment ..............95 Taking Care of the Unexpected ............96 Vehicle Identification ................

  • Page 5: Quick Reference

    Quick Reference KXD 50CC | 70cc 4 Stroke10/40 950mls Spark Plug Torch A7TC | NGK C7HSA Valve Clearance .003” intake / .005” exhaust FENHONG 70CC | 110cc 4 Stroke10/40 950mls Spark Plug Torch A7TC | NGK C7HSA Valve Clearance .003” intake / .005” exhaust YX 125CC | 140CC | 150CC | 160CC | 180CC 4 Stroke10/40 950mls...

  • Page 6: Introduction

    Introduction Congratulations in your decision to purchase a Genuine Thumpstar Recommended Engine. The following manual has been prepared to familiarise you with your engine, and the procedures involved with operating and maintaining the engine.
  • Page 7 Engine Installation Always have a Qualified Mechanic to install your engine. Tools Required: • 8, 10, 12, 13, 14, 17, 19mm socket and spanner • Rubber Mullet • Paint Pen • Thread Lock Glue • Zip Tie Installing an engine into your motorcycle can be different for every motorcycle.

  • Page 8: Fuel Handling

    Precautions should be taken when handling any type of petrochemicals. Gasoline can catch fire, and is toxic to life and the environment. Thumpstar motorbikes recommend the following safety tips to avoid accidents, injury/death: Always turn off the engine when re-fuelling. Do not refuel right after the engine has been running and is still very hot.

  • Page 9: Choke Knob

    Starting & Stopping the Engine Always follow the proper starting procedure described below. PREPARATIONS Before Starting, turn the fuel valve ON and make sure bike is in NEUTRAL. Specially for TSX-C 125 Because it has to be started in Neutral. TSX-C 140 can be started in gear but recommended to start in NEUTRAL STARTING PROCEDURE To restart a warm engine, follow the procedure for High Air Temperature...
  • Page 10 Starting & Stopping the Engine NOTICE: Allowing the kickstarter to snap back freely against the pedal stop can damage the engine case. Warm up the engine by opening and closing with the throttle slightly open, press the start the throttle slightly. About a quarter-minute after the engine starts, push the choke knob in all the way down to fully OFF.
  • Page 11 Starting & Stopping the Engine NOTICE: Extended use of the choke may impair piston and cylinder wall lubrication and damage the engine. FLOODED ENGINE If the engine fails to start after repeated attempts, it may be flooded with excess fuel. To clear a flooded engine: Using The Kickstarter 1.

  • Page 12: Shifting Gears

    Shifting Gears Thumpstar recommended engines from 50cc to 180cc use this gear pattern Some Thumpstars bike, ATV models and Zongshen 190cc is using a different gear pattern including an extra 5th gear. Your motorcycle has four forward gears. To start riding, after engine has been warmed up and the side stand raised: Close the throttle and pull the clutch lever in.
  • Page 13 Shifting Gears Upshift to a higher gear or reduce throttle before engine rpm (speed) gets too high. Downshift to a lower gear before you feel the engine laboring (lugging) at low rpm. NOTICE: Downshifting can help slow your motorcycle, especially on downhills. However, downshifting when engine rpm is too high can cause engine damage.
  • Page 14 Maintenance Schedule for required servicing and step-by-step instructions for specific maintenance tasks. You’ll also find important safety precautions, information on oils, and tips for keeping your Thumpstar looking good. Always use the ring spanner end or socket when possible...

  • Page 15: Maintenance Schedule

    Certified Motorcycle Mechanic knows your motorcycle best and is fully equipped to maintain and repair it. If you decide to do your own mainte- nance, use only Thumpstar Genuine Parts or their equivalents for repair or replacement to ensure the best quality and reliability.

  • Page 16: Maintenance

    Thumpstar recommend any work being carried out on any of our range of dirt bikes should be done by an approved mechanic. The following list has been provided for you by Thumpstar Motorbikes as an advisory process before each ride.

  • Page 17: Air Filter

    Maintenance Whether your Bike has a 2 – Stroke or 4 – Stroke engine, your bike engine relies on a good supply of high quality engine oil. Failure to the oil supply can permanently damage your engine, and oil leaks can cause the loss of control to your Bike.
  • Page 18 Maintenance The Carburetor is also considered part of the throttle system and may also require adjustment. It is not advised to make adjustments whilst the en- gine is running. Repeat adjustments whilst the engine id off and test each adjustment afterwards. To adjust the Carburetor: -Support the motorcycle by means of the side stand -Adjust the idling speed using the adjustment screw (recommended r/min...

  • Page 19: Wiring Diagram

    Wiring Diagram Kill Switch White/Black Ground / Green Wire Black/Yellow Black/Red White Yellow Ignition Coil Pick Up Stator Lighting Coil Ignition Coil Blue/White Black/Yellow Pick Up Black/Red Stator Green White/Black Kill Button...

  • Page 20: Fuel

    If pinging or spark knock persists, consult your Certified Motorcycle Mechanic. Use only unleaded fuel in your Thumpstar. If you ride your Thumpstar in a country where leaded fuel might be available, take precautions to use only unleaded fuel.
  • Page 21 There should be no fuel in the filler neck. 3. After refueling, turn the fuel fill cap clockwise until it is secure. 4. Insert the breather tube in the steering stem nut. If you replace the fuel fill cap, use only a Thumpstar Genuine replacement part.

  • Page 22: Engine Oil

    Engine Oil Using the proper oil, and regularly checking, adding, and changing oil will help extend your engine’s life. Even the best oil wears out. Changing oil helps get rid of dirt and deposits held in the engine. Operating the engine with old or dirty oil can damage your engine.
  • Page 23 Engine Oil Other viscosities shown in the following chart may be used when the aver- age temperature in your riding area is within the indicated range. JASO T 903 standard The JASO T 903 standard is an index for engine oils for 4-stroke motorcycle engines.
  • Page 24 Engine Oil CHECKING & ADDING OIL Upper Level Mark Lower Level Mark Oil Filler Cap /Dipstick 1. Park your motorcycle on a firm, level surface. 2. Clean around the oil fill cap/dipstick and nearby surfaces. 3. Start the engine and let it idle for 3-5 minutes. Stop the engine. Wait 2-3 minutes.
  • Page 25 Engine Oil CHANGING ENGINE OIL Washer Oil Drain Bolt 1. If the engine is cold, start it and let it idle for 3-5 minutes. Turn the engine off. Wait 2-3 minutes for the oil to settle. 2. Park your motorcycle on a firm, level surface. 3.

  • Page 26: Carburetor Adjustment & Tuning Tips

    Carburetor Adjustments & Tuning Tips HIGH ALTITUDE CARBURETOR ADJUSTMENT At high altitude, the standard carburetor airfuel mixture will be too rich. Performance will decrease, and fuel consumption will increase. A very rich mixture will also foul the spark plug and cause hard starting. Operation at an altitude that differs from that at which this engine was certified, for extended periods of time, may increase emissions.
  • Page 27 Carburetor Adjustments & Tuning Tips CARBURETOR CIRCUIT FUNCTIONS The carburetor has several circuits, each providing the fuel/air mixture over a given portion of throttle valve opening. These circuits overlap as show below. MAIN JET JET NEEDLE (TAPERED SECTION) JET NEEDLE (STRAIGHT SECTION) SLOW JET PILOT SCREW...
  • Page 28 Carburetor Adjustments & Tuning Tips CHOKE KNOB The choke knob is used for starting the engine. The choke increases the percentage of fuel in the fuel/air mixture delivered to the engine Used to start a cold engine with air temperature below 35°C (95°F).
  • Page 29 Carburetor Adjustments & Tuning Tips JET NEEDLE The jet needle controls fuel/air mixture over fully closed to 3/4 throttle. The straight section affects throttle response at smaller throttle openings. By changing the position of the clip in its groove, you can improve acceleration at medium low and medium speed.
  • Page 30 Carburetor Adjustments & Tuning Tips STANDARD TUNING RECOMMENDATIONS For the following recommendations to be accurate, you must use the standard settings as a baseline. Also, don’t change any of the settings until you’ve determined what changes are necessary. TSX-C 125 SW - VM22 Adjustment Standard Settings Pilot / Air Fuel Screw Opening...
  • Page 31 There are some unique atmospheric conditions or situations that may require additional adjustments. It should not be necessary to go more than one jet size richer or leaner to fine tune your Thumpstar. If larger jetting changes are necessary, check for air leaks, blocked or restricted exhaust or fuel systems, or a dirty air cleaner.

  • Page 32: Air Cleaner

    Your Certified Motorcycle Mechanic can help you determine the correct service interval for your riding conditions. Your motorcycle’s air cleaner has very specific performance requirements. Use a new Thumpstar Genuine air cleaner specified for your model or an air cleaner of equal quality. NOTICE: Using the wrong air cleaner may result in premature engine wear.

  • Page 33: Cleaning

    Air Cleaner CLEANING Air Filter Screw Mesh 1. Unscrew Bolt 2. Remove the air cleaner 3. Gently wash the air cleaner in clean, nonflammable(high flash point) solvent such askerosene not gasoline. After cleaning,gently squeeze out the remaining solvent.Avoid twisting or wringing the air cleaner.This can tear the foam.
  • Page 34 Throttle UPPER ADJUSTMENT Minor adjustments are generally made with the upper adjuster. Upper Lock Nut Upper Adjuster Rubber Dust Cover 1. Pull the rubber dust cover back. 2. Loosen the upper lock nut on the throttle cable mechanism. 3. Turn the upper adjuster. 4.

  • Page 35: Throttle

    Throttle SECOND ADJUSTMENT The second adjuster is used for major freeplay adjustment, such as after replacing the throttle cables or removing the carburetor. It is also used if you can not get the proper adjustment with the upper adjuster Second Adjuster Locking Nut 1.
  • Page 36 Throttle THROTTLE INSPECTION Throttle Cable Throttle 1. Check that the throttle assembly is positioned properly and the secur- ing bolts are tight. 2. Check for smooth rotation of the throttle from fully open to fully closed in all steering positions. If there is a problem, see your Certified Motorcycle Mechanic 3.

  • Page 37: Clutch System

    Clutch System CLUTCH FREEPLAY Clutch Lever INSPECTION Check Freeplay If necessary, adjust to the specified range. Improper freeplay adjustment can cause premature clutch wear. UPPER ADJUSTMENT Minor adjustments are generally made with the upper clutch cable adjuster. Upper Lock Nut Upper Clutch Cable Adjuster 1.
  • Page 38 Clutch System LOWER ADJUSTMENT The lower clutch cable adjuster is used if the upper clutch cable adjuster is threaded out near its limit or the correct freeplay cannot be obtained. TSX-C 125SW TSX-C 140bW Lower Lock Nut Lower Adjusting Nut 1.

  • Page 39: Valve Clearance

    Valve Clearance Excessive valve clearance will cause noise and eventual engine damage. Little or no clearance will prevent the valve from closing and cause valve damage and power loss. Check valve clearance when the engine is cold at the intervals specified in the Maintenance Schedule. The checking or adjusting of the clearance should be performed while the engine is cold.
  • Page 40 Valve Clearance 6. If it is necessary to make an adjustment, loosen the adjusting screw lock nut and turn the adjusting screw so there is a slight resistance when the feeler gauge is inserted. After completing the adjustment, tighten the adjusting screw lock nut while holding the adjusting screw to prevent it from turning.

  • Page 41: Engine Idle Speed

    Engine Idle Speed The engine must be at normal operating temperature for accurate idle speed adjustment. Ten minutes of stop-and-go riding is sufficient. ( - ) Idle Speed Screw Do not attempt to compensate for faults in other systems by adjusting idle speed.

  • Page 42: Spark Plug

    Spark Plug SPARK PLUG RECOMMENDATION The recommended standard spark plug is satisfactory for most riding con- ditions. Brand / Model Torch A7TC | NGK C7HSA Use only the recommended type of spark plugs in the recommended heat range. NOTICE: Using spark plugs with an improper heat range can cause engine damage. 1.
  • Page 43 Spark Plug 5. Check the spark plug gap, using a wiretype feeler gauge. If adjustment is necessary, bend the side electrode carefully. The gap should be: 0.03-0.04 in (0.8-0.9 mm) Make sure the plug washer is in good condition. If you have to install a new plug, first check the gap.
  • Page 44 Spark Plug Center Electrode Side Electrode Insulator SPARK PLUG COLORING GUIDELINES Condition Spark Plug Appearance Mixture Normal Dark Brown to Light Correct Tan color with Dry Electrode Overheating (Lean) Light Gray or White Lean Color Wet (Rich) Wet or Sooty Rich Remember that in addition to improper jetting: • A lean condition can be caused by air leaks in the inlet tract or exhaust...

  • Page 45: Appearance Care

    Appearance Care Frequent cleaning and polishing will keep your Thumpstar looking newer longer. Frequent cleaning also identifies you as an owner who values your motorcycle. A clean motorcycle is also easier to inspect and service. While you’re cleaning, be sure to look for damage, wear, and gasoline or oil leaks.
  • Page 46 TIPS Here’s helpful advice on how to prepare for an off-road adventure, how to transport and store your Thumpstar unit, and how to be an environmental- ly responsible motorcycle owner. Spraying WD40 or similar product on metal parts will help protect the...

  • Page 47: Preparing For A Ride

    Preparing for a Ride A safe and enjoyable ride begins with good planning and preparation. Always ride with at least one other person in case you have trouble, and let someone know where you’re going and when you expect to return. Before riding in an unfamiliar area, find out in advance if you need special permits, get maps so you can study the terrain, and talk to other riders who know the area.

  • Page 48: Transporting Your Thumpstar

    Transporting your Thumpstar If you use a truck or motorcycle trailer to transport your Thumpstar, we recommend that you follow these guidelines: • Use a loading ramp. • Make sure the fuel valve is off. • Secure the motorcycle in an upright position, using motorcycle tie-down straps.

  • Page 49: Storing Your Thumpstar

    We recommend that you do not transport your motorcycle on its side. This can damage the motorcycle, and leaking gasoline could be a hazard. STORING YOUR THUMPSTAR MOTORCYCLE If you won’t be riding for an extended period, such as during the winter, thoroughly inspect your motorcycle and correct any problem before stor- ing it.
  • Page 50 Storing your Thumpstar 5. Store it in an area protected from freezing temperatures and direct sun- light. 6. Wash and dry your motorcycle. 7. Lubricate the drive chain. 8. Inflate the tires to their recommended pressures 9. Store your motorcycle in an unheated area, free of dampness, away from sunlight, with a minimum of daily temperature variation.

  • Page 51: Troubleshooting

    The items that are serviceable using this Manual are followed by the page number reference in parenthesis. The items that require use of the Thumpstar Manual are followed by an asterisk. POOR PERFORMANCE AT LOW AND UNSTABLE IDLE SPEED CHECK...
  • Page 52 Troubleshooting POOR PERFORMANCE AT LOW AND UNSTABLE IDLE SPEED CHECK POSSIBLE CAUSES...
  • Page 53 Troubleshooting BLOCKED NOT BLOCKED...

  • Page 54: You & The Environment

    You & the Environment Owning and riding a motorcycle can be enjoyable, but you must do your part to protect nature. When you show respect for the land, wildlife, and other people, you also help preserve the sport of off-road riding. Following are tips on how you can be an environmentally responsible motorcycle owner.

  • Page 55: Taking Care Of The Unexpected

    Taking care of the Unexpected With all the challenges you can encounter offroad, there’s a chance that sometime something may go wrong. This section gives practical advice to help you deal with a wide range of problems. Take time to read this section before you ride.
  • Page 56 Thumpstar Certified Motorcycle Mechanic. See or talk to your Thumpstar Certified Motorcycle runs erratically, misfires Mechanic. blubbers (rich fuel mixture) See or talk to your Thumpstar Certified Motorcycle Mechanic. See or talk to your Thumpstar Certified Motorcycle sooty exhaust (rich fuel Mechanic.
  • Page 57 Taking care of the Unexpected IF YOU HAVE A FLAT TIRE How you handle a flat tire on the trail depends on how serious the tube or tire damage is, and what tools and supplies you have with you. If you have a slow leak or a minor puncture, there are two ways to try making a temporary repair: • Use an aerosol tire sealer to seal the puncture and inflate the tube.
  • Page 58 Taking care of the Unexpected IF YOU CRASH Personal safety is your first priority after a crash. If you or anyone else has been injured, take time to assess the severity of the injuries and whether it is safe to continue riding. If you cannot ride safely, send someone for help. Do not ride if you will risk further injury.

  • Page 59: Vehicle Identification

    VIN PLATE ENGINE NUMBER VIN: Vehicle Identification Number is a serial number to identify your Thumpstar Engine: The first 6-7 digit is the engine model number, usually letters and numbers which purpose is for spare parts and detailed specifications. The 2nd group of numbers usually 9 digit is similar to your VIN which is a serial number to identify your particular engine.

  • Page 60: Oxygenated Fuels

    Oxygenated Fuels Some conventional gasolines are being blended with alcohol or an ether compound. These gasolines are collectively referred to as oxygenated fuels. To meet clean air standards, some areas of the United States and Canada use oxygenated fuels to help reduce emissions. If you use an oxygenated fuel, be sure it is unleaded and meets the minimum octane rating requirement.
  • Page 61 Torque Settings USE BLUE MEDIUM STRENGTH THREAD LOCK GLUE NOTE: Put glue on tip of the bolt for glue to work correctly. Places to use Thread Lock Glue...
  • Page 62 Torque Settings (11) (12) (13) (12) (14) (10) (15) (16) (17)
  • Page 63 Torque Settings ITEM TORQUE lbf.ft kgf.m FRAME Steering stem nut 11.0 Fork bridge upper pinch bolts Fork bridge lower pinch bolts Handlebar upper holder bolts Handlebar holder nuts Front axle nut Front axle pinch bolts Rear axle nut 13.1 Chain adjuster lock nuts Mid engine hanger bracket nut Upper engine (engine side)
  • Page 64 Torque Settings (33) (29) (26) (32) (21) (20) (34) (19) (18) (30) (31) (28) (25) (22) (23) (35) (24) (27)
  • Page 65 Torque Settings ITEM TORQUE lbf.ft kgf.m FRAME Front brake master cylinder holder bolts Brake hose bolts Caliper mounting bolts Front brake disc nuts Rear brake disc nuts Brake pedal pivot bolt Spoke (front) 3.68 (rear) Rim locks Subframe bolts (upper) (Iower) Fork center bolt Fork protector bolts...

  • Page 66: Spare Part Catalogue

    Parts Finder Finding Parts at our website Websites https://www.tboltusa.com/ https://www.thumpstar.com.au/ https://www.thumpstar.co.nz/ • Go to our website then copy the part number or ERP CODE in our Spare Part Catalogue and paste it in the search bar then press enter or click the search icon beside it.

  • Page 67: Warranty

    – Picture of the VIN number – Engine faults require a picture of the engine number – Description of the problem To file a warranty claim, please visit your local Thumpstar website, which is located in the footer of the website.

  • Page 68: Disclaimer

    This product is not a toy. This product is intended for experienced adult riders on a closed track. Thumpstar makes no claims as to the suitability of this bike for any specific purpose or user. The products in this manual are designed for competition use for a single rider with proper safety equipment.

  • Page 69: Service Manual

    (age 18 or older) to enter this Agreement and become bound by its term. While all care is taken, any errors and omissions in the item details are unintentional. Therefore, Thumpstar cannot be held liable for any errors or omissions on these adverts. SERVICE MANUAL...

  • Page 70: Title Ownership

    Title Ownership NAME BUYER SIGNATURE SELLER SIGNATURE DATE OF PURCHASE © by Thumpstar. All rights reserved.

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