How to Change the Oil in a 2001 Honda CR125: Complete Guide for MotoSport.com

Shop parts for a 2001 Honda CR125 Dirt Bike.

Changing the oil in your 2001 Honda CR125 is critical for maintaining performance and reliability. Unlike four-strokes, your CR125 is a two-stroke dirt bike, which means you’re changing the transmission (gearbox) oil—not engine oil—since the engine is lubricated by premix.

Tools and Materials You’ll Need

  • Socket wrench with a 17mm socket (for drain bolt; some models use 14mm–check yours)
  • Drain pan
  • Replacement oil (Honda recommends 10W-40 motorcycle gear oil, but Shell RotellaT 15W-40 is a popular choice with owners)
  • Funnel
  • New crush washer for the drain bolt (recommended each oil change)
  • Rag or shop towels
  • Torque wrench (optional, for proper torque on drain bolt)

Preparation Checklist

  • Warm up the engine for 1-2 minutes to help the oil flow out more easily. Warmer oil drains faster and carries out more contaminants.
  • Turn off the engine and place the bike securely on a stand.

Step-by-Step Instructions

  1. Locate the Components:
    • The drain bolt is found at the very bottom of the engine case.
    • The fill cap is next to the kickstarter.
    • The oil level bolt (check bolt) is on the outer clutch cover—this is used to ensure you don’t overfill the transmission.
  2. Drain the Old Oil:
    • Position your drain pan under the bike.
    • Using a 17mm socket (or 14mm on some models), remove the drain bolt and allow all the old oil to drain completely. Be careful not to lose the crush washer.
    • Inspect the oil. A grayish tint means clutch material has worn off, which is normal but signals regular maintenance is needed.
    • If the crush washer is worn or deformed, replace it to prevent leaks.
  3. Reinstall the Drain Bolt:
    • Once oil has drained, reinstall the drain bolt with the crush washer.
    • Tighten snugly, but don’t over-torque–a torque wrench set to manufacturer specs (–13 lb-ft) is ideal.
  4. Add New Oil:
    • Remove the oil fill cap.
    • Pour in the recommended amount of fresh gear oil—approximately 0.65 liters (650 ml) for the 2001 CR125.
    • To ensure proper level, remove the check bolt. Add oil until it just begins to seep from this hole, indicating a full transmission.
    • Reinstall the fill and check bolts securely.
  5. Inspect for Leaks:
    • Wipe down any spilled oil from the cases and bolts.
    • Start the bike briefly, turn it off, and check for leaks around the drain, check, and fill bolts.

Specific Tips for the 2001 Honda CR125

  • The procedure for the 2001 model is nearly identical to CR125s from other years. Confirm your drain bolt size (commonly 17mm, but sometimes 14mm).
  • Always use a new crush washer with each oil change for a consistent seal.
  • Check oil after a short ride: if the clutch feels grabby or the oil has a milky or metallic appearance, plan to change more frequently.
  • If you see significant metal flakes in used oil, inspect your clutch plates or transmission components.

Oil Recommendations

  • Use Honda GN4 10W-40 motorcycle oil or a high-quality equivalent. Shell RotellaT 15W-40 is popular among experienced owners for both performance and cost-effectiveness.

Environmental Concerns

  • Collect the used oil and take it to a recycling center—never dispose of it in the trash or on the ground.

Final Notes

  • Changing the transmission oil every five rides or after any muddy or wet ride is recommended for best reliability.
  • Always tightening bolts to correct torque specifications can prevent stripped cases or leaks.
  • Record your maintenance in a log for reference.

This guide is proprietary to MotoSport.com and crafted to make your maintenance as smooth as possible. Enjoy your ride.

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Shop Oil Fillers and Drain Plugs for a 2001 Honda CR125 Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.