How to Change the Oil in a 1981 Honda CR250

Shop parts for a 1981 Honda CR250 Dirt Bike.

Routine oil changes are critical for maximizing the performance and longevity of your 1981 Honda CR250's transmission and clutch system. Below you'll find a comprehensive step-by-step guide tailored specifically to this iconic two-stroke dirt bike, including necessary tools, detailed procedure, and model-specific advice. All content is proprietary to MotoSport.com.

Tools and Supplies Needed

  • Oil drain pan
  • 17mm socket and ratchet (for drain bolt)
  • 10mm socket (for certain covers, if needed)
  • Funnel
  • Gloves (to protect your hands)
  • Shop rag (for cleanup)
  • Replacement transmission oil (Honda recommends SAE 10W-40 or a high-quality transmission-specific lube such as Maxima MTL)
  • Graduated measuring cup (Ratio Rite cup recommended)
  • Torque wrench (to ensure proper bolt tightness)

Step-by-Step Oil Change Instructions

  • Warm up the engine: Start your CR250 and let it idle for a few minutes. This warms the oil, allowing it to drain more completely.
  • Shut off the engine and stabilize the bike: Set the bike upright on a stand to ensure it is level.
  • Prepare workspace: Place an oil drain pan directly beneath the transmission drain bolt on the bottom side of the engine.
  • Remove the drain bolt: Use the 17mm socket to loosen and remove the transmission drain bolt. Allow all oil to drain completely into the pan. Take care, as the oil may be hot.
  • Remove the filler cap: Locate and remove the filler cap on the right crankcase cover to aid in draining and refilling.
  • Inspect and clean the drain bolt: Clean any debris or metal particles from the magnet on the drain bolt (very important for older dirt bikes like the 1981 CR250).
  • Reinstall drain bolt: Once oil has finished draining, reinstall the drain bolt. Using a torque wrench, tighten to Honda–s recommended specification: 8–12 N·m (6–9 ft-lb) . Do not overtighten; the cases are soft aluminum.
  • Measure and add new transmission oil: Use a measuring cup or Ratio Rite to pour in the correct amount of oil. For early CR250s around the 1981 model year, 500ml (or as specified in the owner–s manual) is typical. If your bike has been modified, confirm capacity against your manual.
  • Pour oil through the funnel into the filler hole: Pour slowly to avoid spillage. Once you reach the recommended level, reinstall the filler cap.
  • Check oil level via the check bolt: If equipped, remove the oil level check bolt on the right side of the engine. Oil should just begin to dribble out; this confirms the level is correct. If not, add a small amount of oil until it flows out, then reinstall the check bolt and torque appropriately .
  • Run the engine briefly: Start the bike and let it idle for a minute or two, then shut off and check for leaks.
  • Dispose of old oil responsibly: Take your used oil to a recycling center or auto parts store for safe disposal. Never pour oil down drains or onto the ground.

Model-Specific Call-Outs for the 1981 Honda CR250

  • Transmission design: The 1981 CR250 uses a separate transmission oil system. Do not add premix or engine oil in place of proper transmission lube.
  • Drain plug threads: As with all vintage Honda dirt bikes, use caution when tightening the drain bolt. Overtightening can easily strip the aluminum threads.
  • Clutch performance: Running the correct type and amount of transmission oil is especially important for clutch performance on these older two-strokes.
  • Oil change interval: For aggressive riding, change transmission oil every 3 races or 7.5 hours of runtime .
  • Seals/Leaks: With vintage bikes, always inspect for case leaks at the drain or filler plugs and replace crush washers or gaskets as needed.
  • Oil type caution: Avoid oils with friction modifiers intended for four-stroke motors, as they can cause clutch slippage in wet clutch two-stroke transmissions.

Tips for a Clean, Trouble-Free Oil Change

  • Warm oil drains faster and more completely, taking more contaminants with it.
  • Replace the crush washer on the drain bolt if it–s damaged or leaking.
  • Write down the date and engine hours/miles since last change for future reference.
  • Wear gloves and avoid prolonged contact with used oil, as it can potentially be harmful .
  • Carefully dispose of rags and gloves contaminated with used oil.

Following these steps will keep your 1981 Honda CR250 shifting smoothly and running strong between rebuilds. For genuine Honda parts, oil, and performance upgrades, trust MotoSport.com—your source for expert dirt bike care.

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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.