How to Change the Oil in a 1982 Honda CR125: Step-by-Step Guide

Shop parts for a 1982 Honda CR125 Dirt Bike.

Changing the oil in your 1982 Honda CR125 is crucial for maintaining peak performance and longevity of the transmission. This classic two-stroke motocross bike relies on fresh transmission oil to keep shifting smooth, protect gears, and prevent costly repairs. Here’s a detailed, proprietary guide from MotoSport.com on how to complete an oil change, including the tools you’ll need and specific advice for the ’82 CR125.

Tools and Supplies Needed

  • Metric socket set (at least up to 17mm for the drain bolt)
  • Ratchet or wrench
  • New sealing washer (for the drain bolt)
  • Dirt bike stand or triangle stand
  • Oil drain pan
  • Funnel
  • Shop rags
  • Owner's manual (for torque specs, but provided below where possible)
  • Recommended transmission oil (consult your owner’s manual): Generally, a high-quality 10W-40 motorcycle-specific oil or a two-stroke gear oil (per Honda recommendations, use Pro Honda HP Transmission Oil or equivalent SAE 80/85 gear oil)
  • Measuring cup (to measure correct oil volume)
  • Gloves (optional for cleanliness)

Step-By-Step Oil Change Process

  1. Warm Up the Engine
    • Start the bike and let it idle for about 2-3 minutes. Warm oil drains more thoroughly, taking suspended contaminants with it.
    • Shut off the engine once warm.
  2. Stabilize the Bike
    • Place the CR125 on a bike stand to keep it upright and level.
  3. Locate the Oil Drain Bolt
    • The oil drain bolt is typically found on the bottom left side of the engine case. On the 1982 CR125, it is a 17mm bolt.
    • Place your drain pan directly beneath the bolt.
  4. Remove the Oil Drain Bolt
    • Slowly loosen and remove the drain bolt using the 17mm socket or wrench. Be careful—oil may start pouring out quickly once the bolt is free. Keep an eye out for a sealing washer; replace it if it’s damaged or compressed.
  5. Let the Oil Drain Completely
    • Allow all oil to drain from the transmission case. Tilting the bike gently side-to-side can help remove additional residue.
  6. Install the Drain Bolt
    • Wipe the drain bolt threads clean. Install a new sealing washer onto the bolt. Hand-tighten the bolt, then finish snugging with the socket. Torque recommendation is generally 21 lbf–ft (29 N–m, as specified for later CR125 models; lacking a specific value for 1982, do not overtighten as you risk stripping the threads in the aluminum case) .
  7. Add Fresh Transmission Oil
    • Locate and remove the filler cap (typically atop or to the side of the right engine case).
    • Use a funnel to pour in the recommended amount of oil: approximately 650 ml (0.69 US qt) for the 1982 CR125.
    • If in doubt, refer to your owner’s manual for exact oil capacity.
  8. Check the Oil Level
    • Some models use a sight glass, but the ’82 CR125 uses an oil check bolt or dipstick. After filling, upright the bike and install (but don’t overtighten) the filler cap.
    • Remove the oil check bolt or dipstick to verify that the oil level is correct. If low, add oil in small increments.
  9. Reinstall All Plugs and Clean Up
    • Install and snug the oil check bolt and filler cap. Wipe away oil drips from the engine case for a clean finish.
    • Start the engine and let it idle for 30 seconds, then shut it down and recheck the oil level. Adjust as needed.
  10. Dispose of Old Oil Responsibly
    • Pour the used oil into a container and take it to a recycling center or hazardous waste facility. Never dump it in the trash or down a drain .

Specific Call-Outs For the 1982 Honda CR125

  • The 1982 CR125 requires specific attention to the oil capacity measurement; always verify with the existing owner’s manual or a service guide if possible as vintage models may vary slightly due to engine or case revisions.
  • It has a two-stroke engine—remember, the transmission/clutch case shares oil, but the engine itself is lubricated via premix in your fuel.
  • Do not overtighten aluminum case bolts, as the 1982’s engine cases are relatively soft. Hand-tighten followed by a gentle snug with a torque wrench if available.
  • Always use the correct oil spec: Most modern off-road transmission oils in 10W-40 or dedicated two-stroke transmission oils work well.
  • If you see excessive clutch debris or metallic particles in the drained oil, inspect the clutch plates and gears for wear.

Final Safety and Maintenance Tips

  • Change the transmission oil every 10-15 riding hours or after any heavy, muddy, or sandy use.
  • Inspect the area around the drain and filler plugs for leaks in the days following an oil change.
  • Document oil changes in a maintenance log for your CR125—this helps with resale and troubleshooting down the line.

A well-maintained 1982 Honda CR125 delivers decades of reliable power. With these steps, you’ll keep your bike running smoothly for years to come—only from MotoSport.com.

Related Shopping Categories

Shop Motor Oil for a 1982 Honda CR125 Dirt Bike.

Shop Oil Filters for a 1982 Honda CR125 Dirt Bike.

Shop Oil Drain Pans for a 1982 Honda CR125 Dirt Bike.

Shop Tools for a 1982 Honda CR125 Dirt Bike.

Shop Oil Fillers and Drain Plugs for a 1982 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.