How to Change the Oil in a 1985 Suzuki RM250

Shop parts for a 1985 Suzuki RM250 Dirt Bike.

Changing the oil in your 1985 Suzuki RM250 is a fundamental maintenance task that helps increase the longevity and performance of your bike’s engine and transmission. This guide will walk you through the process, highlight the tools required, and flag important model-specific call-outs for your RM250.

Tools & Materials Needed

  • Socket set and ratchet (to fit the oil drain plug, typically 17mm or 19mm)
  • Allen key set (for the oil check bolt; most commonly 8mm for this model)
  • Funnel (for adding new oil)
  • Clean rags
  • Drain pan (to collect old oil)
  • New oil (SAE 10W-40 motorcycle gear oil, non-EC or MA-rated)
  • Torque wrench (to ensure correct tightness)
  • Parts cleaner (optional, for cleaning up any mess)
  • Replacement crush washer for the drain plug
  • Motorsport gloves (optional for cleaner hands)

Step-by-Step Instructions

  1. Warm Up the Engine
    • Start the engine and let it idle for 1–2 minutes. This warms the oil, allowing it to drain more thoroughly.
  2. Stabilize the Bike
    • Find a flat, level surface. Use a bike stand if available, or have someone help you hold the bike upright and vertical.
  3. Locate the Filler Cap and Drain Plug
    • The oil filler cap is usually found on the top right side of the transmission case—remove it to allow air in, which aids draining.
    • The oil drain plug is directly underneath the engine.
  4. Drain the Oil
    • Place your drain pan beneath the engine’s drain plug.
    • Using your socket and ratchet, carefully loosen and remove the drain plug.
    • Allow all the oil to drain out. Inspect the old oil for any metallic particles which could indicate engine wear.
    • Replace the crush washer on the drain plug to prevent leaks.
    • Reinstall and tighten the oil drain plug to 21 N·m (15 lb-ft) with a torque wrench.
  5. Refill with Fresh Oil
    • Insert a funnel in the filler opening.
    • Pour in 750 ml (0.8 US quarts) of SAE 10W-40 motorcycle-grade gear oil.
    • Do not overfill; check the level (see next step).
  6. Checking Oil Level
    • Locate the oil check bolt: It is hidden behind the chain guard, tucked behind some wires. Use an Allen key to remove this bolt and inspect the oil level; oil should drip out only slightly when full

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    • Alternatively, some models have a sight window or dipstick on the case—consult your owner’s manual for specifics.
    • If the oil does not reach the bolt hole level, add a small amount at a time until it does.
  7. Reinstall the Filler Cap and Check for Leaks
    • Replace the filler cap and tighten it by hand.
    • Start the bike and let it idle for a minute, then check under the engine for any leaks.
    • Shut off the engine, recheck the level with the check bolt, and top-off if necessary.
  8. Dispose of Used Oil Properly
    • Take the used oil to a certified recycling center or local auto parts store.

Model-Specific Call-Outs for the 1985 Suzuki RM250

  • The 1985 RM250 uses a separate transmission oil (not the same as pre-mix for the 2-stroke fuel), and this oil needs regular changing every 10–15 riding hours, or after every few races, to avoid premature clutch or gearbox wear

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  • Capacity is 750 ml during routine oil changes.
  • The oil check bolt is often hidden behind wires and/or the chain guard—removal may require minor disassembly for access

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  • Always use motorcycle-specific wet clutch-compatible oil (JASO MA/MA2) to avoid clutch slippage or damage.
  • Double-check the torque on the drain plug; overtightening can strip the aluminum case threads.

Helpful Tips

  • Do not use automotive engine oil, as it often lacks the additives needed for a wet clutch and can cause slipping.
  • Keep a maintenance log—note oil brand, type, and change intervals for best results.
  • Periodically inspect for leaks around the drain plug and shifter shaft after every few rides.

This proprietary guide is provided exclusively by MotoSport.com for 1985 Suzuki RM250 owners looking to keep their machine running strong with regular oil changes.

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Shop Oil Fillers and Drain Plugs for a 1985 Suzuki RM250 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.