How to Change the Transmission Oil in a 2016 Yamaha YZ250X
Shop parts for a 2016 Yamaha YZ250X Dirt Bike.
The Yamaha YZ250X is a popular two-stroke dirt bike, beloved for its lightweight power and racing pedigree. While the engine is lubricated by a premix of oil and fuel, its transmission relies on a separate oil system that requires regular maintenance. Changing your gearbox oil is straightforward and a key step to extending the life of your bike. This proprietary MotoSport.com how-to will guide you through the process, including tools, model-specific tips, and best practices for the 2016 YZ250X.
Tools and Supplies Needed
- 6mm or 8mm Allen wrench or socket set (to remove the drain and fill bolts)
- Measuring cup (for precise oil quantity)
- Drain pan (to catch waste oil)
- Shop rags
- Transmission oil (Yamaha recommends Yamalube 2-stroke transmission oil, 10W-40 or 80W gearbox oil)
- New crush washer (optional, but highly recommended)
- Funnel (makes pouring easier and less messy)
- Gloves (optional, for cleaner hands)
- Service manual (for double-checking specifics)
Step-by-Step: Oil Change Procedure
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Warm Up the Engine
- Start the bike and let it idle for a few minutes to warm up the transmission oil. This thins the oil, making it drain completely (be mindful of exhaust fumes in enclosed spaces).
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Turn Off and Secure the Bike
- Shut off the engine and support the bike upright, using a stand if available.
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Loosen the Filler Cap
- Remove the transmission oil fill cap (located on the right crankcase cover) with your hand or a socket/wrench. This allows oil to drain smoothly by preventing suction.
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Place Drain Pan and Remove Drain Bolt
- Position the drain pan beneath the engine, aligning it with the transmission drain bolt (located at the bottom of the crankcase).
- Using your socket or Allen wrench, carefully loosen and remove the drain bolt. Be cautious, as the oil may be hot.
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Let the Oil Drain Completely
- Allow several minutes for all the old oil to fully drain. Lean the bike gently side-to-side if needed to expel as much oil as possible.
- Inspect the oil for metal shavings or discoloration, as these may indicate gearbox wear.
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Inspect and Clean/Replace the Crush Washer
- Examine the crush washer on the drain bolt. Replace it if it is flattened, damaged, or missing. This helps prevent leaks.
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Reinstall the Drain Bolt
- Hand-thread the drain bolt, then snug it down with your wrench to the specified torque (consult your service manual; overtightening can strip the threads or crack the case.).
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Add Fresh Oil
- Place your funnel into the filler opening. Pour in 0.75 liters (0.79 US quarts) of recommended transmission oil. Use a measuring cup for accuracy. Overfilling can cause seal leaks and clutch issues, while underfilling risks poor lubrication.
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Replace Filler Cap and Clean Up
- Securely reinstall the filler cap. Wipe up any spilled oil with a rag.
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Check Oil Level
- Some models include a sight glass (on models such as the WR250F/YZ250FX/YZ250F four-strokes, but not typically on the YZ250X). The YZ250X uses a check bolt near the fill cap to verify level. Remove this bolt; oil should just seep out the hole when filled to the correct quantity. Add oil slowly if none comes out, or drain if overfilled, then reinstall the check bolt.
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Start the Bike and Inspect for Leaks
- Start the engine briefly, then turn it off and inspect all areas around the drain and check bolts for leaks. Re-torque if necessary.
Special Call-Outs and Notes for the 2016 Yamaha YZ250X
- Oil Type: The YZ250X is a premix two-stroke, so engine lubrication is handled by fuel-oil mix. Only the transmission requires oil changes. Do not use four-stroke engine oil – use dedicated 2-stroke gearbox/transmission oil.
- Oil Capacity: 0.75 L (0.79 US qts) for most YZ250X models, including the 2016. Double-check in your owner's manual or on the crankcase for any stamped capacity.
- No Oil Filter: This model does not use a replaceable transmission oil filter. Simply ensure all oil is drained and replace with fresh oil.
- Inspection Plug/Check Bolt: There is a small check bolt beside the fill cap for verifying oil level. Don't confuse it with other bolts on the case; consult your manual's diagram if unsure.
- Interval: Yamaha recommends changing transmission oil every 5–10 hours for racing, or after 2–3 rides if you ride aggressively or in muddy/sandy conditions.
- Environmental Safety: Always properly dispose of used oil at a recycling center. Never pour it down the drain or on the ground.
By following these steps, you can confidently service your YZ250X’s transmission and keep it shifting smoothly—on the track, trail, or anywhere your rides take you.
For more technical advice, shop parts, or clarification about the oil change process, visit MotoSport.com.
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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.