How to Change the Oil in a 1977 Honda CR250

Shop parts for a 1977 Honda CR250 Dirt Bike.

Changing the oil in your 1977 Honda CR250 is a crucial maintenance task that ensures long engine life and top performance on the track or trail. This guide provides a step-by-step, proprietary process for MotoSport.com readers, including all tools needed and specific tips for this vintage two-stroke dirt bike.

Tools and Supplies You’ll Need

  • 17mm socket (for drain bolt)
  • 10mm socket (for oil check bolt)
  • Oil drain pan
  • Rubber gloves
  • Rag or paper towels
  • Funnel
  • Measuring jug (Ratio Rite cup recommended)
  • Replacement copper washer (if old washer is damaged)
  • Maxima MTL transmission oil, SAE 10W-40 or equivalent gear oil

Important Model-Specific Notes for 1977 Honda CR250

  • The 1977 CR250 uses a two-stroke engine, so the “oil change” refers to the transmission oil, not premix inside the fuel tank.
  • Always look for the oil fill and check bolts on the right side (clutch cover area). Honda typically uses a 10mm bolt with a copper washer as the oil level check bolt, located near the clutch cover.
  • Vintage models like the ‘77 use simple drain and fill systems — there’s no oil filter to replace.
  • Use .7 liters (700cc) of gear oil for the fill, but always confirm with your owner’s manual. If you don’t have one, 700cc is a safe bet for this model year.

Step-by-Step Oil Change Instructions

  1. Warm Up The Engine:
    • Start your CR250 and let it idle for a few minutes. This helps the oil flow out smoothly with impurities suspended for a more complete drain.
      (This is recommended for all CR250's including your 1977 model.)
  2. Prepare Your Work Area:
    • Set the bike upright on a stand or center block to keep it stable and level.
    • Put on gloves and slide the oil drain pan under the engine.
  3. Remove the Drain Bolt:
    • Locate the 17mm drain bolt at the bottom side of the right crankcase cover.
    • Carefully loosen and remove the bolt, and let the used oil drain fully into the pan.
    • If the copper washer is damaged or missing, replace it to prevent leaks. This is a common issue on older CR250s.
  4. Remove the Oil Filler Cap:
    • Unscrew the oil filler cap on the right crankcase cover. This allows air to enter and helps oil flow out completely.
  5. Reinstall the Drain Bolt:
    • Once oil has stopped dripping, wipe the area clean and reinstall the drain bolt with a fresh copper washer.
    • Be careful not to overtighten. Torque the bolt to 8–12 Nm (6–9 ft-lbs) to avoid stripping threads on the older cases.
  6. Pour in New Oil:
    • Use a measuring jug (Ratio Rite or similar) to measure 700cc (0.7L) of SAE 10W-40 or equivalent gear oil.
    • Use a funnel to avoid spills and pour the oil into the fill hole.
  7. Check the Oil Level:
    • Find the oil check bolt (10mm, with a copper washer) on the right side of the case, just to the right of the Honda logo on the clutch cover.
    • With the bike level, remove the check bolt. If oil gently flows out of the bolt hole, the level is correct. If not, add oil slowly through the filler cap until it begins to flow out, then replace both the check bolt and filler cap.
  8. Cleanup & Final Steps:
    • Wipe off any excess oil, check for leaks around the drain and check bolts.
    • Run the engine for a minute, then recheck for leaks and confirm the oil level if necessary.
    • Dispose of used oil responsibly—never pour it down the drain or onto the ground.

Extra Tips for 1977 CR250 Owners

  • This model lacks an oil filter, so regular oil changes are vital for clutch and gear longevity.
  • Check the condition of both the drain bolt and washers during each oil change; these can wear or crush over decades of use.
  • Vintage Honda cases are soft aluminum—always use proper torque, never overtighten, and replace stripped bolts or threads as needed.
  • For high-performance riding or racing, change the oil every 3 rides or 7–8 hours.

By following these steps, you’ll keep your 1977 Honda CR250 in peak running condition. Performing this maintenance yourself not only saves money but also helps you become more familiar with the unique quirks of vintage Honda two-stroke motorcycles. For all your dirt bike parts, oil, gear, and Honda CR250 questions, trust MotoSport.com—your source for everything dirt bike.

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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.