How to Change the Oil in a 1987 Yamaha PW50: A Complete MotoSport.com Guide
Shop parts for a 1987 Yamaha PW50 Dirt Bike.
Keeping your 1987 Yamaha PW50 running smoothly for years starts with proper maintenance, and changing the transmission oil regularly is an essential part. This robust, easy-to-follow guide from MotoSport.com walks you through every step—what tools you’ll need, the procedure, and critical call-outs unique to the PW50. Follow these instructions to keep your mini dirt bike at its best, whether you’re a seasoned mechanic or a first-timer.
Tools and Supplies Needed
- 12mm socket or wrench (for drain bolt)
- Torque wrench (recommended for correct reassembly)
- Oil catch pan (to collect old oil)
- Clean rag (for cleanup and wiping parts)
- 300ml of SAE 10W-30 or 10W-40 non-energy conserving oil (Yamalube or similar, per Yamaha spec)
- Replacement crush washer for the drain bolt (optional, but recommended)
- Funnel (for pouring new oil, optional but helpful)
- Gloves (optional)
Model-Specific Call-Outs for the 1987 Yamaha PW50
- Transmission Oil Only:– On the PW50, you change the transmission (gearbox) oil—not engine oil—since it is a two-stroke and engine lubrication comes from pre-mix or injector system.
- Oil Amount:– The correct amount is 300ml of oil for the transmission.
- Oil Type:– Do not use oils labeled as "Energy Conserving II" or higher, or any diesel-spec CD or higher. These can cause clutch slippage. Stick to SAE 10W-30 or 10W-40, non-energy conserving, preferably motorcycle-specific like Yamalube. Avoid any chemical additives in the oil.
- Drain Plug Torque:– Tighten the drain bolt to 10 foot-pounds (14Nm).
- Warm Up First:– Run the engine for a few minutes to thin the oil and make draining easier.
- Crush Washer:– Inspect and replace the crush washer on the drain plug to prevent leaks.
- Check for Leaks:– After completing the oil change, run the engine and inspect for any leaks.
- Cleanliness:– Do not allow dirt or debris to enter the gearbox during the process.
Step-by-Step Oil Change Instructions
- Warm the Engine:– Start the PW50 and let it idle for a few minutes. This helps the oil flow more freely when draining and ensures contaminants are suspended for easier removal
- Tip:– Never change oil on a cold engine; you’ll leave contaminants behind.
- Stabilize the Bike:– Put the bike securely on its center stand or use a stable stand that keeps the bike upright and level.
- Locate the Oil Drain Bolt:– Find the transmission oil drain bolt underneath the engine. Place your oil catch pan directly beneath it.
- Remove Oil Filler Cap:– Remove the oil filler cap from the right-hand side of the bike. Set it aside on a clean rag. This step allows air to flow and the oil to drain out faster.
- Remove the Drain Bolt:– Using your 12mm socket or wrench, carefully unscrew the oil drain bolt. Keep a hand under the bolt to prevent dropping it in the oil pan. Watch for the crush washer–it may stick to the engine or bolt.
- Drain the Oil:– Let all the old oil fully drain into your pan. This could take several minutes.
- Inspect and Clean:– Clean the drain bolt and filler cap with your rag. If your crush washer is damaged or flattened, replace it with a new one.
- Reinstall Drain Bolt:– Once oil has stopped dripping, reinstall the drain bolt (with its crush washer) and hand-tighten. Use your torque wrench to tighten to 10 foot-pounds (14Nm). Do not overtighten.
- Add New Oil:– Using your funnel, pour 300 milliliters (0.3L) of the recommended oil into the filler hole.
- Replace Filler Cap:– Reinstall and tighten the oil filler cap securely by hand.
- Start and Check:– Start the engine and allow it to idle for several minutes. Check around the drain bolt and oil filler cap for leaks. If you see any drips, shut off the bike and investigate.
- Dispose of Old Oil Responsibly:– Pour the old oil into a sealed container and take it to any recycling center or auto parts store that accepts used oil. Never pour oil onto the ground or in the trash.
Additional Tips for PW50 Owners
- Change the transmission oil after the first 5–10 hours of riding a new or rebuilt engine, then every 20–30 hours or at least once a season after that.
- Regular Visual Checks:– Before every ride, check for leaks and make sure oil level is adequate.
- If the bike is used in harsh conditions (mud, frequent submersion, racing), change the oil more often.
Important Safety and Performance Reminders
- Never overfill or underfill:– 300ml is precise; too much or too little oil can harm engine and clutch life.
- Make sure you use the correct type of oil to avoid clutch slippage and premature wear.
- Keep the area clean—foreign materials in the transmission can cause damage. Wipe the area before, during, and after the oil change.
- If you find metal flakes in the oil during a change, consult a qualified mechanic—this could indicate a bigger problem.
That’s it. With just a little time and the right technique, you’ll keep your 1987 Yamaha PW50 running strong season after season. For more model-specific tips, OEM parts, and the best oils, trust MotoSport.com for all your dirt bike maintenance needs.
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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.