Automotive
Motorcycling
BULLET500
Service Manual

Royal Enfield Bullet 500cc Cast Iron Engine Service Manual (2004)

Table of Contents

  1. Introduction
  2. Engine Specifications
  3. Routine Maintenance
  4. Engine Removal & Installation
  5. Fuel System
  6. Electrical System
  7. Transmission & Clutch
  8. Cooling System
  9. Troubleshooting
  10. Glossary

Introduction

Welcome to the service manual for the 2004 Royal Enfield Bullet 500cc Cast Iron Engine. This manual covers essential maintenance procedures and troubleshooting for the engine and associated systems. Ensure that you follow these procedures carefully to maintain optimal performance and reliability.

Engine Specifications

  • Model: Royal Enfield Bullet 500cc Cast Iron
  • Engine Type: Single-cylinder, 4-stroke, air-cooled
  • Displacement: 500cc
  • Bore x Stroke: 84mm x 90mm
  • Compression Ratio: 8.5:1
  • Fuel System: Carburetor (UCAL BS29)
  • Ignition System: Transistorized Coil Ignition (TCI)
  • Lubrication: Wet sump
  • Oil Capacity: 2.5 liters (including filter change)

Routine Maintenance

1. Engine Oil Change

  • Interval: Every 3,000 km or 6 months (whichever comes first)
  • Procedure:
    1. Warm up the engine for a few minutes.
    2. Remove the oil drain plug and let the oil drain completely.
    3. Replace the oil filter if necessary.
    4. Refill with the recommended 20W50 oil.
    5. Tighten the drain plug and check the oil level.
  • Recommended Oil: Castrol GTX 20W50 or similar.

2. Air Filter Cleaning/Replacement

  • Interval: Every 6,000 km
  • Procedure:
    1. Remove the air filter cover and housing.
    2. Remove the filter element.
    3. Clean the filter with compressed air or wash it with mild detergent if it's a foam filter.
    4. Replace if damaged or excessively worn.

3. Spark Plug Maintenance

  • Interval: Every 6,000 km
  • Procedure:
    1. Remove the spark plug using a spark plug wrench.
    2. Inspect the plug for wear and carbon build-up.
    3. Clean or replace the spark plug as necessary.
  • Recommended Spark Plug: NGK BP7ES

Engine Removal & Installation

Removal:

  1. Preparation:
    • Drain all fluids (oil, coolant).
    • Disconnect the battery.
    • Remove the exhaust system.
    • Disconnect fuel lines and electrical connections.
    • Loosen engine mounting bolts.
  2. Lift the Engine:
    • Carefully lift the engine out of the frame with the help of an engine hoist or a friend.

Installation:

  1. Position the Engine:
    • Align the engine with the frame and carefully lower it into place.
  2. Secure the Mounting Bolts:
    • Tighten the engine mounting bolts to the specified torque.
  3. Reconnect Components:
    • Reconnect the fuel system, electrical connections, and exhaust.

Fuel System

Carburetor Inspection & Cleaning

  • Interval: Every 12,000 km or if the bike runs roughly.
  • Procedure:
    1. Remove the carburetor from the intake manifold.
    2. Clean the carburetor jets using carb cleaner.
    3. Inspect the float and needle valve for wear.
    4. Reassemble and reinstall the carburetor.

Fuel Line Replacement

  • Interval: Every 2-3 years.
  • Procedure:
    1. Disconnect the fuel line from the carburetor and fuel tank.
    2. Replace with high-quality fuel line material.

Electrical System

Battery Maintenance

  • Interval: Every 6 months.
  • Procedure:
    1. Check the battery voltage using a multimeter.
    2. Clean the battery terminals and ensure they are free of corrosion.
    3. If the battery is not holding charge, replace it.

Charging System Check

  • Procedure:
    1. Start the engine and measure the voltage across the battery terminals.
    2. It should read between 12.5V to 14.5V when the engine is running.
    3. If the voltage is outside this range, inspect the alternator and rectifier.

Transmission & Clutch

Clutch Adjustment

  • Procedure:
    1. Check the free play in the clutch lever.
    2. Adjust the clutch cable using the adjuster screw to achieve 5-10mm free play.

Gearbox Oil Change

  • Interval: Every 10,000 km.
  • Procedure:
    1. Drain the old oil from the gearbox.
    2. Refill with SAE 90 Gear Oil (about 1 liter).

Cooling System

Radiator Inspection & Coolant Change

  • Interval: Every 12,000 km.
  • Procedure:
    1. Inspect the radiator for leaks and debris.
    2. Drain the old coolant and flush the system with water.
    3. Refill with a mixture of water and 50% anti-freeze.

Troubleshooting

Engine Won’t Start

  • Possible Causes:
    • Dead battery: Check voltage and charge/replace.
    • Fuel delivery issue: Inspect fuel lines and carburetor.
    • Ignition system failure: Test spark plug and ignition coil.

Overheating

  • Possible Causes:
    • Low coolant levels: Refill the cooling system.
    • Blocked radiator: Clean the radiator fins.
    • Clogged air filter: Replace or clean the air filter.

Glossary

  • Odometer: A device used to measure the distance traveled by a vehicle.
  • Carburetor: A device that mixes air and fuel for combustion.
  • Torque: A measure of rotational force applied to a component, often specified for tightening bolts.
  • Compression Ratio: The ratio of the cylinder volume at the bottom of the piston stroke to the volume at the top.

For further support, please consult the official Royal Enfield Bullet 500cc Service Manual or visit your local Royal Enfield service center.

Last updated on March 30, 2025
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