How to Change the Oil in a 1987 Yamaha YZ490 – MotoSport.com Exclusive Guide
Shop parts for a 1987 Yamaha YZ490 Dirt Bike.
Changing the oil in your 1987 Yamaha YZ490 is crucial for prolonging engine life and ensuring optimal performance. This guide provides proprietary, step-by-step instructions tailored specifically for your YZ490, covering the unique aspects of this vintage two-stroke dirt bike.
Tools and Materials Needed
- Socket set (8mm-14mm, confirm drain plug size in your manual or as marked on your bike)
- Drain pan
- Funnel
- Clean rags or shop towels
- Plastic or rubber gloves (optional)
- Yamaha YZ490 recommended oil (SAE 10W-30 SE motor oil or Yamalube 4-cycle oil)
- Replacement drain plug washer (optional but recommended)
- Torque wrench (optional, for precise tightening)
Oil Specifications for the 1987 YZ490
- Transmission oil capacity (periodic change): 750 cm³ (0.80 US qt)
- Transmission oil capacity (overhaul): 800 cm³ (0.85 US qt)
- Recommended oil: Yamalube 4-cycle oil or SAE 10W-30 SE motor oil
Always use oil specified for two-stroke transmissions, as it lubricates both the transmission and clutch.
Step-by-Step Oil Change Procedure
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Warm Up the Engine
- Start your YZ490 and let it idle for about 1 minute. This warms up the transmission oil, allowing it to drain more thoroughly.
- Do not run the engine in an enclosed area—exhaust fumes are highly toxic.
-
Prepare the Motorcycle
- Turn off the engine and place your bike securely on a stand or level surface.
- Ensure the motorcycle is upright so oil drains completely.
-
Locate and Remove the Drain Plug
- The transmission oil drain plug is typically found at the bottom of the crankcase. Refer to your owner’s or service manual for the precise location.
- Position the drain pan under the plug.
- Using the correct socket, carefully loosen and remove the drain plug. Be cautious—oil may be hot.
-
Drain the Oil
- Allow all the oil to drain into the pan.
- If possible, tilt the bike slightly side to side to ensure full drainage.
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Inspect and Replace the Washer
- Check the drain plug washer for wear or damage. Replace it if necessary to avoid leaks.
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Reinstall the Drain Plug
- Replace the drain plug securely. If you have a torque wrench, refer to your manual for the correct torque setting (typically 14-20 ft-lbs, but verify for your YZ490).
-
Refill with New Oil
- Remove the transmission oil filler plug.
- Using a funnel, pour in the recommended amount and type of oil: 750 cm³ (0.80 US qt) for a standard change or 800 cm³ (0.85 US qt) if you’re completing an overhaul.
- Replace the filler plug.
-
Check Oil Level
- Locate the oil level check screw on the right side of the engine.
- With the bike upright, remove the check screw:
- If oil flows out, the correct level is reached. If not, add small amounts until it does.
- Reinstall the check screw securely.
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Clean Up
- Wipe away any spilled oil from the engine and frame.
- Dispose of used oil properly at a recycling center or auto parts store.
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Final Checks
- Start the engine and let it idle briefly.
- Check under the bike for leaks at the drain and filler plug locations.
- Recheck your oil level after the engine idles, adding if necessary.
Special Call-Outs for the 1987 Yamaha YZ490
- This model uses a separate transmission oil system, so the oil you change is for the gearbox and clutch, not engine lubrication (since it’s a two-stroke and engine lubrication is by pre-mix).
- Be sure to use a quality transmission/clutch oil rated for two-stroke gearbox use—car motor oils may cause clutch slippage.
- The drain and fill plugs are prone to stripping; use only the correct-size sockets and never overtighten.
- Factory specified oil capacities should not be exceeded—adding extra oil does not offer added protection and can cause performance issues.
- Original Yamaha part numbers for washers and plugs can still be sourced through specialty suppliers to ensure vintage authenticity and fit.
MotoSport.com Tip: Always record your oil change date and hours ridden. On vintage machines like the YZ490, regular maintenance is especially important for reliability and preserving value.
This comprehensive guide is proprietary content for MotoSport.com, tailored to the needs of 1987 Yamaha YZ490 owners. Ride safe, and enjoy the lasting performance of your classic YZ.
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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.