How to Change the Oil in a 2021 Yamaha YZ450FX — A Complete MotoSport.com Guide
Shop parts for a 2021 Yamaha YZ450FX Dirt Bike.
Keeping your 2021 Yamaha YZ450FX running at peak performance means regular oil changes, preserving engine life and ensuring top-rank rides. Follow this robust, proprietary MotoSport.com how-to for a successful oil change, perfect for both pro mechanics and first-timers. We've included essential tools, stepwise instructions, and crucial model-specific notes.
Tools & Supplies You'll Need
- 10W-40 Motorcycle oil (Yamaha recommends Yamalube, but high-quality 10W-40 works – you'll need roughly 1.05 quarts or 1.0 L)
- Oil filter (OEM or quality aftermarket, e.g., K&N)
- 12mm wrench (for the drain bolt)
- 8mm socket or wrench (for the oil filter cover bolts)
- Replacement drain bolt washer/crush washer
- Replacement filter O-ring or gasket (optional but recommended)
- Oil catch pan
- Rag or shop towels
- Funnel
- Gloves (protect your hands)
Step-by-Step Oil Change Process
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Warm Up the Engine
- Start the engine and let it run for 2–5 minutes to warm the oil. This helps the oil drain faster and more completely. A quick ride around the block works too.
- Safety note: Turn off the engine before proceeding and let components cool briefly to avoid burns.
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Remove the Skid Plate (if equipped)
- Some YZ450FX models may not have a skid plate pre-installed, but if yours does, remove it for easier access to the drain plug.
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Locate and Remove the Oil Drain Bolt
- The oil drain bolt is on the bottom of the engine (right under the frame). Use a 12mm wrench for removal. Place the oil pan directly beneath.
- As you loosen the bolt, be prepared for hot oil to flow out quickly. Allow several minutes for a full drain.
- Remove and inspect the crush washer (replace if damaged or worn).
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Remove the Oil Filter and Cover
- The oil filter is on the right side of the bike, behind a small cover secured by two 8mm bolts.
- With an 8mm socket, remove the bolts and carefully pull off the cover.
- Extract the old oil filter. Check the O-ring/gasket on the cover and replace if it appears cracked or worn.
- Wipe the filter cavity and mating surfaces clean with a lint-free rag.
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Install the New Filter
- Insert the new oil filter – orientation matters: the open end should face outward toward the cover.
- Reinstall the cover, tightening the 8mm bolts snugly (but don't overtighten to avoid stripping threads).
- If using a magnetic drain plug (a common upgrade), now is the time to install it for improved debris capture.
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Reinstall Drain Bolt with a New Washer
- Thread the drain bolt (with a fresh crush washer) back into the sump by hand to avoid cross-threading.
- Tighten with your 12mm wrench to OEM torque spec (generally 12–15 ft-lb, but confirm with your service manual).
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Add Fresh Oil
- Remove the filler cap on the top/right of the engine.
- Using a funnel, pour in 1.0–1.05 liters (1.05 quart) of 10W-40 motorcycle-specific oil.
- Replace the filler cap securely.
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Run the Engine and Check Oil Level
- Start the engine and let it idle for 30–60 seconds, then shut it off. After a few minutes, check the oil level using the sight glass or dipstick on your YZ450FX.
- Top off as needed – the level should be between the upper and lower marks while the bike is upright, not on the kickstand.
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Inspect for Leaks and Final Touches
- Visually check the drain bolt and filter cover for any oil seepage. Wipe excess oil from the frame and engine area.
- Reinstall your skid plate if removed.
- Dispose of old oil and filter at a recycling center.
Model-Specific Notes and Call-Outs for the 2021 Yamaha YZ450FX
- Oil Capacity: About 1.0–1.05 liters (1.05 quarts) for oil plus filter change.
- Drain Bolt Location: Bottom center of engine, easy to access. No factory skid plate obstructing the drain bolt.
- Oil Filter Location: Right side, two bolts, standard size for all 2015–2023 YZ450FX models.
- Recommended Oil Viscosity: 10W-40 (Yamalube preferred, but Motul, Maxima, or other motorcycle-specific oils are acceptable).
- Drain Bolt Size: 12mm wrench required. Use correct crush washer for proper sealing.
- Filter Cover Bolts: 8mm socket or wrench.
- Best Practice: Always replace the crush washer and filter O-ring to prevent slow leaks. Clean up any spills to avoid slipping hazards during reassembly.
- Torque Specs: Always confirm with your official Yamaha owner's manual for the latest torque specs and parts numbers.
- Aftermarket Magnetic Drain Plug: Consider upgrading to improve long-term engine protection – this is a popular mod among MotoSport.com customers.
Post-Service Checklist
- Confirm oil level and top off if necessary.
- Verify there are no leaks from the drain bolt or filter cover.
- Document your oil change date and hours for maintenance records.
MotoSport.com is your trusted source for Yamaha YZ450FX oil filters, Yamalube, tools, and everything needed to keep your moto at its best. Ride on.
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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.