How to Change the Oil in a 1991 Yamaha XT350: Step-by-Step Guide

Shop parts for a 1991 Yamaha XT350 Dirt Bike.

Properly changing the oil in your 1991 Yamaha XT350 is crucial for preserving engine life and performance. Below you'll find a robust, proprietary MotoSport.com guide covering all tools needed, every step in the process, and model-specific call-outs for the XT350.

Tools and Supplies Needed

  • SAE 10W-40 or 20W-40 motorcycle oil (approx. 1.3–1.4L for filter change)
  • Yamaha Genuine Oil Filter
  • Socket wrench set (including 12mm and 10mm sockets; check your bolt heads)
  • New crush washer for drain bolt (recommended)
  • Oil drain pan
  • Funnel
  • Clean shop rags or paper towels
  • Solvent (for cleaning reusable oil filter, if reusing)
  • Torque wrench
  • Gloves (optional)

Model-Specific Call-Outs for 1991 Yamaha XT350

  • Always begin the oil change with the motorcycle placed perfectly upright and on a level surface, as the XT350’s oil level window can give inaccurate readings if tilted

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  • This model uses approximately 1.3L of oil for an oil change and 1.4L if you're replacing the oil filter

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  • The recommended engine oil is SAE 10W-40 or 20W-40 Type SE, but check your climate for proper viscosity

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  • The drain plug torque spec is 43 Nm (31 ft-lb) and the oil filter cover screws should be tightened to 10 Nm (7.2 ft-lb)

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Step-by-Step Oil Change Instructions

  1. Warm up the engine. Start your XT350 and let it idle for about 3–5 minutes to warm the oil slightly. This allows the oil to drain more thoroughly. Don’t overheat the engine; you want the oil to be warm, not hot, for safety and best drainage

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  2. Stabilize the motorcycle. With the engine off, park the bike on level ground and keep it upright–use a stand or have an assistant help. An angled bike can give a false oil reading and lead to under- or over-filling

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  3. Remove the oil filler cap. Unscrew the oil filler cap on the right crankcase to allow air and help oil drain smoothly

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  4. Place the oil drain pan below the engine. Ensure the pan is positioned under the drain bolt to catch all the draining oil.
  5. Remove the drain bolt and air bleed screw. Using the appropriate wrench (often 12mm for the drain), carefully remove the drain plug from the bottom of the crankcase. Also, remove the small air bleed screw (if fitted; check your model) to prevent vacuum-lock and ensure complete drainage

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  6. Let the oil fully drain. Wait several minutes until the flow slows to a drip. Be patient; removing as much old oil as possible is critical for engine health.
  7. Remove oil filter cover and replace filter.
    • Locate the oil filter cover—usually on the right side of the engine.
    • There are three screws securing the cover. Remove the bottom screw first to allow oil to drain out of the filter cavity.
    • Carefully take off the cover and pull out the filter.
    • Inspect the filter. If using a reusable type, clean thoroughly with solvent and let dry. If using disposable, replace with a new Yamaha filter.
    • Check both O-rings (on filter and cover); replace if damaged.
  8. Install new filter and reassemble.
    • Ensure the new (or cleaned) filter and O-rings are seated properly.
    • Reinstall the oil filter cover, tightening the screws to 10 Nm (7.2 ft-lb).
  9. Install drain bolt (with new washer if possible). Hand thread the drain bolt to avoid cross-threading, then torque to 43 Nm (31 ft-lb)

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  10. Add fresh oil. Using a funnel, pour new oil into the filler cap opening–start by adding about 1.3L. Be careful not to overfill.
  11. Check oil level.
    • Let the motorcycle sit upright for several minutes so oil can settle.
    • With the engine off, use the round sight glass (oil level window) on the right crankcase to check the level. The oil should be between the min and max marks; add oil as needed, a little at a time

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  12. Start the engine and inspect.
    • Check for oil leaks at the drain bolt, oil filter cover, and filler cap.
    • Let the engine idle for 1–2 minutes, then turn off and check oil level again—top off if needed.

Additional Tips for 1991 Yamaha XT350 Owners

  • Change oil every 4,000 miles (or 6,000 km), or more frequently if you ride in dirty/dusty conditions

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  • If oil appears milky, it may indicate coolant contaminating the engine oil; inspect further before riding

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  • After an oil change, dispose of old oil and filter properly at a recycling center.

Conclusion

The 1991 Yamaha XT350 oil change is straightforward with the right tools and procedural care. Adhering to the above steps and paying attention to torque specs, oil type, and cleanliness will keep your XT350 reliable for years. For all your parts, filters, and oil needs, trust MotoSport.com for genuine Yamaha products and maintenance advice.

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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.