Yamaha KT100SEC Owner's Service Manual
  1. Manuals
  2. Brands
  3. Yamaha Manuals
  4. Utility Vehicle
  5. KT100SEC
  6. Owner's service manual
Yamaha KT100SEC Owner's Service Manual

Yamaha KT100SEC Owner's Service Manual

Racing kart
Hide thumbs
Table of Contents

Quick Links

RACING KART
OWNER' S SERVICE MANUAL
7YP-28199-SE
Table of Contents
loading

Related Manuals for Yamaha KT100SEC

Summary of Contents for Yamaha KT100SEC

  • Page 1 RACING KART OWNER’ S SERVICE MANUAL 7YP-28199-SE...
  • Page 2 It is not possible to put an entire mechanic's education into one manual, so it is assumed that persons using this book to perform maintenance and repairs on Yamaha racing kart have a basic understanding of the mechanical concepts and procedures inherent in racing kart repair technology.

  • Page 3: How To Use This Manual

    HOW TO USE THIS MANUAL CONSTRUCTION OF THIS MANUAL This manual consists of chapters for the main categories of subjects. (See "Illustrated symbois") This is a chapter with its symbol on the upper right of each page. 1st title This title appears on the upper of each page on the left of the chapter 2nd title symbol.

  • Page 4: Engine ･････････････････････････････････････････････

    ILLUSTRATED SYMBOLS (Refer to the illustration) SPEC INFO GENERAL INFORMATION SPECIFICATIONS REGULAR INSPECTION AND ADJUSTMENTS INSP ENGINE CARBURETOR ELECTRICAL CARB ELEC Special tool Oil capacity Lubricant Tightening Specified value, Service limit Resistance (Ω), Voltage (V), Electric current (A) Engine speed Apply engine mixing oil Apply lightweight lithium-soap base grease Apply locking agent (LOCTITE...
  • Page 5 INDEX GENERAL INFORMATION INFO SPECIFICATIONS SPEC REGULAR INSPECTION INSP AND ADJUSTMENTS ENGINE CARBURETOR CARB ELECTRICAL ELEC...

  • Page 6: Table Of Contents

    CONTENTS REMOVING THE CLUTCH ･････････････････････････ REMOVING THE CRANKSHAFT ･･････････････････ CHAPTER 1 GENERAL INFORMATION REMOVING THE BEARING ････････････････････････ CHECKING THE ENGINE PARTS ･･･････････ INCLUDED PARTS ････････････････････････････････ CHECKING THE CYLINDER HEAD ･･･････････････ SWITCH BRACKET ･････････････････････････････････ 4-10 CHECKING THE CYLINDER ･････････････････････ INSTALLING THE BATTERY ･･･････････････････････...
  • Page 7 INCLUDED PARTS INFO INCLUDED PARTS SWITCH BRACKET Install the switch stay between the steering wheel and its support. Switch button side INSTALLING THE BATTERY 138mm 4-φ6.5 1. Install: Battery box ●   113mm 2. Install: Battery ●   3. Connect: Battery lead ●...

  • Page 8: Starting ･･･････････････････････････････････････････

    STARTING INFO STARTING STARTING THE ENGINE 1. Start the engine by pushing the start switch If the engine fails to start by pushing the start switch , release the switch, wait 30 seconds, and then try again. CAUTION: Do not crank the engine more than 4 seconds ●...

  • Page 9: Carburetor

    B: 0.03 mm or less D：45.8∼45.9mm Piston: Piston to cylinder clearance 0.030∼0.035mm Type Plain type (Cr-plated) End gap 0.4∼0.5mm Carburetor: KT100SEC Type WALBRO WB-21 Standard setting Idle needle 1-1/3±1/6 (80±10 min.) High speed needle 5/12±1/6 （25±10 min.） Carburetor: KT100SEJ Type...

  • Page 10: Electrical

    SPEC ELECTRICAL SPECIFICATIONS ELECTRICAL SPECIFICATIONS Battery: Type GT7B-4 manufacturer GS yuasa Operation voltage Rating 6.5Ah Starter motor: Type 5M05-289 manufacturer Mitsuba Operation voltage Output 0.3kw Starter relay: Type B768042 manufacturer Jideco Voltage rating DC12V (30 min.) Min. operation voltage DC8 V or less Open voltage DC4 V or less Coil resistance...
  • Page 11 Remarks Thread N・m（kg・m） Pitch diameter Cylinder head 1.25 18∼23 （1.8∼2.3） Spark plug 1.25 15∼25 （1.5∼2.5） Crankcase YAMAHA Bond No. 1215 10∼16 （1.0∼1.6） Crankcase cover1 10∼16 （1.0∼1.6） Crankcase cover2 6∼9 （0.6∼0.9） Stay1 mounting bolt 10∼16 （1.0∼1.6） Gear3 mounting bolt 6∼9 （0.6∼0.9）...
  • Page 12 SPEC CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM Starter relay Sub lead Positive lead 1 (battery - starter relay) Starter switch Positive lead 2 (starter relay - starter motor) Engine stop switch Negative lead 1 (battery - coupler) Fuel hose Negative lead 2 (coupler - starter motor) Throttle cable...
  • Page 13 INSP MAINTENANCE INTERVALS MAINTENANCE INTERVALS After Every Every Every Every Storage break-in race third fifth required Item Remarks (or 100 km) (or 300 km) (or 500 km) (or 1000 km) CYLINDER HEAD Inspect ○ ○ Clean ○ Carbon deposits Tightening ○...
  • Page 14 INSP MAINTENANCE INTERVALS After Every Every Every Every Storage break-in race third fifth required Item Remarks (or 100 km) (or 300 km) (or 500 km) (or 1000 km) CARBURETOR Inspect (Needle adjuster) ○ ○ Standard position (Metering lever) ○ ○ Bend/spring free length Clean ○...
  • Page 15 INSP ENGINE ENGINE ADJUSTING THE ENGINE IDLING SPEED 1. Adjust: Idle needle   ● Turning in the idle needle screw will lean out the mixture at low speeds, and turning out it will enrich the mixture. Standard idle needle screw position SEC：...
  • Page 16 INSP ENGINE ADJUSTING THE THROTTLE PEDAL 1. Inspect: Throttle pedal free play   ● Throttle pedal free play 2∼5mm Out of specification → Adjust. 2. Adjust: Throttle pedal free play ●   Loosen the locknut and turn the adjuster ･ in fully.
  • Page 17 INSP ELECTRICAL ELECTRICAL CHECKING THE BATTERY WARNING Batteries generate explosive hydrogen gas ●   and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: Charge batteries in a well-ventilated area. ●  ...
  • Page 18 INSP ELECTRICAL NOTE: Since MF batteries are sealed, it is not possible to check the charge state of the battery by measuring the specific gravity of the electrolyte. Therefore, the charge of the battery has to be checked by measuring the voltage at the battery terminals.
  • Page 19 INSP ELECTRICAL NOTE: The charge state of an MF battery can be ●   checked by measuring its open-circuit voltage (i.e., the voltage when the positive terminal is disconnected). No charging is necessary when the open- ●   circuit voltage equals or exceeds 12.8 V. b.
  • Page 20 INSP ELECTRICAL CAUTION: Never remove the MF battery sealing caps. ●   Do not use a high-rate battery charger since it ●   forces a high-amperage current into the battery quickly and can cause battery overheating and battery plate. If it is impossible to regulate the charging ●...
  • Page 21 INSP ELECTRICAL 5. Inspect: Battery terminal ●   Dirt → Clean with wire brush Loose → Connect 6. Apply the grease. Battery terminal ●   7. Install: Battery ●   8. Connect: Battery lead ●   (to battery terminal) CAUTION: First, connect the positive lead , then the negative lead...
  • Page 22 INSP ELECTRICAL CHECKING THE SPARK PLUG NOTE: Remove a mud and dust from the cylinder head before removing the spark plug. 1. Inspect: Electrode ●   Wear/Damage → Replace. Dirt/Carbon deposit → Clean the spark plug with a spark plug cleaner or wire brush. Wear/Damage →...
  • Page 23 INSP ELECTRICAL CHECKING THE IGNITION TIMING 1. Remove: Spark plug ●   Crankcase cover2 ●   Gear3 ●   Stay1   ● 2. Attach: Dial gauge stand set ●   Dial gauge stand set 90890-01252 3. Rotate the rotor counter clockwise until the piston reaches top dead center (TDC).
  • Page 24 INSP ELECTRICAL ADJUSTING THE COIL GAP 1. Remove: Crankcase cover2 ●   Gear3 ●   Stay1 ●   2. Measure the air gap between the rotor ･ and coil assembly Standard air gap 0.4mm Out of specification → Adjust. 3. Adjust: Air gap ●...
  • Page 25 EXPLODED DIAGRAM EXPLODED DIAGRAM ENGINE Bearing Crankcase (L, R) Cylinder head Oil seal Joint pipe Cylinder head gasket Small end bearing Drive sprocket Spark plug Piston pin Cylinder Piston Absorber A Cylinder gasket Piston ring Absorber B Crank assembly Piston pin clip...
  • Page 26 EXPLODED DIAGRAM TCI MAGNETO STARTER MOTOR Engine starter switch Gear1 Rotor Crankcase cover1 Engine stop switch Coil assembly Crankcase cover2 Needle bearing Lead wire Starter motor Bearing Plate Idle gear Gear3 Needle bearing Stay1...
  • Page 27 EXPLODED DIAGRAM SL CLUTCH ASSY Circlip (seeger ring) Stud bolt (adapter shaft) Spacer Thrust washer (shim) Sprocket Z10 Clutch body Sprocket Z11 Key (woodruff key) M5 screw Clutch cover Clutch drum Chain guard Roller gauge M8 stopper screw (stop dowel)
  • Page 28 DISASSEMBLING THE ENGINE DISASSEMBLING THE ENGINE REMOVING THE CYLINDER HEAD AND CYLINDER 1. Remove: Spark plug ●   Cylinder head mounting nut ●   Cylinder head ●   2. Remove: Cylinder head gasket ●   Cylinder mounting nut   ● Cylinder ●...
  • Page 29 DISASSEMBLING THE ENGINE 3. Remove: Piston ring ●   While opening its meeting ends, remove the piston ring on the side opposite to them. CAUTION: Take care not to scratch the piston or damage the piston ring by expanding it more than necessary.
  • Page 30 DISASSEMBLING THE ENGINE 2. Remove: Rotor ●   When removing the rotor, use the rotor puller Rotor puller 90890-01362 CAUTION: Take care not to screw in the two bolts of the rotor puller too far. They may contact the stator and damage it. 3.
  • Page 31 DISASSEMBLING THE ENGINE 4. Loosen: M8 stopper screw (stop dowel) ●   Stud bolt (adapter shaft) ●   5. Remove: Clutch body ●   Reference For removal, use the specialized tool. 6. Remove: Key (woodruff key) ●   REMOVING THE CRANKSHAFT 1.
  • Page 32 DISASSEMBLING THE ENGINE 2. Remove: Bolt (crankcase) ●   3. Remove: Right crankcase ●   Make sure the crank separating tool body is parallel with the crankcase. Crankcase separating tool: 90890-01135 CAUTION: Take care so that the oil seal lip is not damaged. 4.
  • Page 33 CHECKING THE ENGINE PARTS CHECKING THE ENGINE PARTS CHECKING THE CYLINDER HEAD 1. Inspect: Carbon deposits   ● Use a rounded scraper CAUTION: Avoid scratching the aluminum. 2. Measure: Cylinder head warpage ●   Warp limit 0.015mm Out of specification → Replace...
  • Page 34 CHECKING THE ENGINE PARTS CHECKING THE CYLINDER 1. Inspect: Exhaust port carbon deposition ●   Use a rounded scraper CAUTION: Avoid scratching the aluminum. 2. Inspect: Cylinder wall ●   Score marks → Repair. Use #400∼600 grit wet sandpaper. Damage → Rebore or Replace. 3.
  • Page 35 CHECKING THE ENGINE PARTS CHECKING THE PISTON AND PISTON PIN 1. Inspect: Piston crown carbon deposits ●   Use a scraper. Ring groove carbon deposits ●   Use a used piston ring. Wear/Scratches/Damage → Replace. 2. Measure: Piston diameter ●  ...
  • Page 36 ;; ; ; ; CHECKING THE ENGINE PARTS CHECKING THE PISTON CLEARANCE Feeler gauge Method to use a feeler gauge. ●   Feeler gauge How to insert the piston and the feeler gauge Piston is as shown: The piston pin is inserted in parallel with the crankshaft axis.
  • Page 37 CHECKING THE ENGINE PARTS CHECKING THE CLUTCH 1. Inspect: Clutch drum ●   Clutch body ●   Wear/Scratch/Damage → Replace. 2. Inspect: Drive sprocket ●   Wear/Damage → Replace the clutch drum. 3. Inspect: Clutch shoe thickness ●   Standard shoe thickness 3.3mm Wear limit Roller gauge...
  • Page 38 CHECKING THE ENGINE PARTS CHECKING THE GEAR1, 3 AND IDLE GEAR 1. Inspect: Gear1 ●   Gear3 ●   Idle gear ●   Wear/Damage → Replace. CHECKING THE STARTER MOTOR GEAR 1. Inspect: Starter motor gear   ● Wear/Damage → Replace. CHECKING THE CRANKSHAFT 1.
  • Page 39 CHECKING THE ENGINE PARTS CHECKING THE CRANKCASE OIL SEAL 1. Inspect: Oil seal ●   Wear/Damage → Replace. CHECKING THE CRANKCASE 1. Inspect: Right crankcase ●   Left crankcase ●   Wear → Repair. Use #400∼600 grit wet sandpaper. 4-15...
  • Page 40 INSTALLING THE ENGINE INSTALLING THE ENGINE INSTALLING THE CRANKSHAFT 1. Install: Crankshaft bearing ●   Install the bearing by pressing it on the side having the manufacture's marks or numbers. NOTE: Install the bearing with its outer race 0.5mm above the crank case surface. 2.
  • Page 41 INSTALLING THE ENGINE INSTALLING THE CRANKCASE 1. Clean the contacting surface of crankcase (left and right) before applying the sealant. 2. Install: Dowel pin ●   3. Install: Right crankcase ●   Crankshaft ●   Install the crankshaft by installing tools. Crankshaft installing pot 90890-01274 Crankshaft installing bolt...
  • Page 42 INSTALLING THE ENGINE 5. Install: Crankcase mounting bolt ●   Tighten all bolts in 2∼3 steps and be sure to tighten in numbered order as shown. Crankcase mounting bolt 1.0∼1.6kg・m 6. Install: Engine bracket ●   Engine bracket mounting bolt 2.5∼3.0kg・m INSTALLING THE PISTON RING AND PISTON 1.
  • Page 43 INSTALLING THE ENGINE 3. Install: Piston ●   Piston pin ●   Piston pin clip ●   The arrow on the piston dome must point to exhaust side. Piston pin clip NOTE: Before installing the piston pin clip, cover the ●...
  • Page 44 INSTALLING THE ENGINE 4. Install: Cylinder head ●   Cylinder head 1.8∼2.3kg・m Tighten all bolts in 2∼3 steps and be sure to tighten in numbered order as shown. INSTALLING THE TCI MAGNETO 1. Temporarily install: Plate ●   2.install: Woodruff key ●...
  • Page 45 INSTALLING THE ENGINE 2. Install: Stay1 mounting bolt   ● Stay1 ●   Gear3 mounting bolt ●   Gear3 ●   Gear1 ●   Idle gear ●   3. Install: Crankcase cover2 mounting bolt ●   Crankcase cover ●   INSTALLING THE CLUTCH 1.
  • Page 46 INSTALLING THE ENGINE 4. Tighten: M8 stopper screw (stop dowel) ●   Apply locking agent (LOCTITE M8 stopper screw (stop dowel) 2.0kg・m 5. Tighten: Thrust washer (shim) ●   Roller gauge ●   Apply the grease onto the roller gauge. 6.
  • Page 47 4-23...
  • Page 48 CARB CARBURETOR REMOVING AND DISASSEMBLY THE CARBURETOR Preparation for removal Remove the air box. Remove the fuel hose. ● ● Remove the throttle cable. Remove the pulse hose. ● ●...
  • Page 49 CARB CARBURETOR SERVICE POINTS Clean the removing parts before inspecting. ● Extent of removal REMOVING THE CARBURETOR REMOVING THE METERING DIAPHRAGM REMOVING THE INLET NEEDLE VALVE REMOVING THE PUMP DIAPHRAGM Extent of removal Order Parts name Q'ty Remarks Washer Air box joint1 Gasket Carburetor assembly Gasket...
  • Page 50 CARB SL CARBURETOR REMOVING AND DISASSEMBLY THE SL CARBURETOR Preparation for removal Remove the air box. Remove the fuel hose. ● ● Remove the throttle cable. Remove the pulse hose. ● ●...
  • Page 51 CARB SL CARBURETOR SERVICE POINTS Clean the removing parts before inspecting. ● Order Parts name Q'ty Remarks Bolt Manifold Gasket Carburetor assembly Screw Pump cover Pump gasket Pump diaphragm Metering diaphragm gasket Diaphragm assembly Metering diaphragm cover Screw Inlet needle valve Metering lever pin Metering lever Spring...
  • Page 52 CARB CARBURETOR REMOVAL POINTS REMOVING THE CARBURETOR 1. Disconnect: Fuel hose ●   Negative pressure hose ●   Throttle cable ●   WARNING Plug the fuel hose so that fuel does not run out. NOTE: Always clean up spilled fuel immediately. 2.
  • Page 53 CARB CARBURETOR INSTALLING THE CARBURETOR 1. Install: Carburetor ●   Air box ●   Hose clamp ●   Carburetor gasket 2. Connect: Throttle cable ●   Fuel hose ●   Negative pressure hose ●   3. Adjust: Throttle pedal free play ●...
  • Page 54 ELEC WIRING DIAGRAM WIRING DIAGRAM Engine stop switch Engine starter switch White/Black Black Black Black White/Black Black Black Blue White/Black Black Blue Black Battery TCI unit Starter relay Black Black Starter motor Earth...

  • Page 55: Ignition System

    ELEC IGNITION SYSTEM TROUBLESHOOTING 1. Spark plug Spark plug condition ● NO SPARK Spark plug type ● INTERMITTENT SPARK Spark plug gap ● Check Refer to the CHAPTER 3. 1. Spark plug Standard spark plug 2. Minimum spark gap B9EVX（NGK） 3.
  • Page 56 ELEC IGNITION SYSTEM 3. Engine stop switch 5. Secondary coil resistance Check the engine stop switch for continuity. Disconnect the high tension lead from the ● ● spark plug. CONTINUITY Disconnect the spark plug cap from the ● CONTINUITY high tension lead. Replace the engine Connect the pocket tester (x1kΩ) to the ●...
  • Page 57 ELEC STARTING SYSTEM TROUBLESHOOTING 2. Starter motor Connect the positive battery terminal ● If the starter motor will not operate. starter motor lead with a jumper lead Check 1. Battery 2. Starter motor 3. Starter relay 4. Engine starter switch Black 5.
  • Page 58 ELEC STARTING SYSTEM 4. Engine starter switch 3. Starter relay Disconnect the starter relay coupler from Check the engine starter switch for continuity. ● ● sub lead wire. CONTINUITY Connect the pocket tester (x1Ω) and the ● CONTINUITY battery to the starter relay as shown. Replace the engine Battery terminal →...
  • Page 60 YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN JAPAN...

This manual is also suitable for:

Kt100sej

Table of Contents