How to Change the Oil in a 1991 Honda CR250

Shop parts for a 1991 Honda CR250 Dirt Bike.

Changing the transmission oil on your 1991 Honda CR250 is a straightforward process that can extend the life of your clutch and gearbox. This guide is proprietary to MotoSport.com and tailored specifically for the 1991 CR250, highlighting the necessary steps, tools, and unique tips for this classic model.

Tools and Supplies Needed

  • 17mm socket or wrench (for drain bolt)
  • 10mm socket or wrench (some models may require this for engine covers)
  • Drain pan
  • Rubber gloves
  • Funnel
  • Ratio Right measuring cup or graduated cup
  • Rags or paper towels
  • Replacement transmission oil: Honda recommends SAE 10W-40 for this period or a high-quality 2-stroke transmission oil like Maxima MTL
  • Torque wrench (for reinstalling bolts to factory specs)

Specifications for the 1991 Honda CR250

  • Capacity:– 0.7 liters (0.74 US qt) after 1989, so the 1991 model requires 700mL or 23.6 fl oz at each change
  • Recommended oil:– 10W-40 4-stroke oil or equivalent high-quality 2-stroke transmission oil
  • Drain bolt torque:– 8-12 N-m (6-9 ft-lb)
  • Oil check bolt:– Use to confirm correct level—oil should flow out when at proper fill

Step-By-Step Procedure

  1. Warm-Up the Engine
    • Start the bike and let it idle for several minutes to warm the transmission oil. This lowers the oil’s viscosity, ensuring it drains thoroughly.
  2. Position the Bike and Prepare Tools
    • Place the bike on a stable, flat surface and set it on a stand for better access. Slide your drain pan under the engine.
  3. Remove the Oil Filler Cap
    • Unscrew the oil filler cap on the right crankcase cover. This allows the oil to drain more smoothly. Set the cap aside somewhere clean.
  4. Drain the Oil
    • Use a 17mm socket to remove the drain bolt at the bottom of the engine.
    • Allow oil to flow completely into the drain pan. Be cautious—oil may be hot.
    • Inspect the drain bolt for metal shavings or debris. Clean the bolt before reinstalling it.
  5. Reinstall the Drain Bolt
    • Thread the bolt back in by hand, then use a torque wrench to tighten it to 8–12 N-m (6–9 ft-lb). Avoid over-tightening—aluminum cases can strip easily.
  6. Fill with Fresh Oil
    • Measure 700ml (0.7 liters/23.6 fl oz) of your chosen oil using a Ratio Right cup.
    • Using a funnel, pour the oil into the filler hole.
  7. Check the Oil Level
    • Start the engine and let it warm up briefly, then turn it off. Remove the oil check bolt (located on the right crankcase).
    • If oil starts to flow out of the check bolt hole, the level is correct. If not, add oil in small increments until oil just begins to flow out, then reinstall the check bolt and torque as needed.
  8. Final Checks and Clean-Up
    • Install the oil filler cap securely. Wipe any residual oil from the engine and floor.
    • Properly dispose of used oil according to local regulations.

Model-Specific Tips for the 1991 Honda CR250

  • Capacity and Maintenance:– Always use 0.7 liters (700ml) of quality transmission oil. Change oil every three races or after 7.5 hours of riding for best durability and performance — this is especially critical for vintage two-strokes .
  • Thread Care:– The cases are aluminum—use a torque wrench and never over-tighten drain or check bolts to avoid damaging threads .
  • Oil Choice:– The 1991 CR250 transmission is designed for non-motor oil (use gear/transmission oil if possible). Some modern clutch and gearbox oils, like Maxima MTL, are preferable. Avoid ATF or engine oil, as they may not offer adequate shear or clutch protection.
  • O-Rings and Seals:– Inspect the drain bolt’s crush washer or O-ring. Replace if damaged or deformed to prevent leaks.

Why Regular Oil Changes Matter

  • Extends clutch and transmission life by keeping parts well lubricated and debris-free
  • Prevents gear slipping and shifting problems common in older two-stroke designs
  • Protects aluminum engine cases—old oil can become acidic and corrode soft metals over time

Conclusion

Changing your 1991 Honda CR250 transmission oil is quick, easy, and crucial for keeping your vintage racer running strong. By following these steps—using quality oil, proper tools, and paying attention to unique model details—you’ll protect your investment and enjoy better rides. For all your oil and maintenance needs, trust MotoSport.com to keep your ride at peak performance.

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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.