How to Change the Oil in a 1999 Yamaha XT350: A Complete Guide

Shop parts for a 1999 Yamaha XT350 Dirt Bike.

  • Estimated Time:– 30–60 minutes
  • Skill Level:– Beginner/Intermediate

Tools and Supplies Needed

  • Oil pan (to catch old oil)
  • Socket wrench set (with metric sizes)
  • Torque wrench
  • New oil filter (Yamaha OEM or quality aftermarket)
  • Replacement O-ring(s) (for the filter cover, if needed)
  • Funnel
  • Clean rags
  • New engine oil:– SAE 20W40 (or SAE 10W40; see model note below)

Oil and Capacity Details

  • Oil type:– SAE 20W40 or SAE 10W40, SE specification
    Yamaha recommends SAE 20W40 Type SE Motor oil, though SAE 10W40 is also common. If using synthetic oil, ensure it meets Yamaha–s specs.
  • Oil capacity:– 1.3 L (1.14 Imp qt, 1.34 US qt) for a simple oil change;
    1.4–L (1.23 Imp qt, 1.44–US–qt) when replacing the oil filter

Step-by-Step Instructions

  1. Warm Up the Engine
    Start your XT350 and let it idle for 3–5 minutes. Warming the oil thins it, ensuring it drains out smoothly. Do not let the engine get too hot;–just warm enough so the case feels slightly warm to the touch.
  2. Stabilize the Bike
    Place the bike upright on a level surface. This ensures an accurate oil level reading and prevents spills.
  3. Remove Oil Fill Cap
    Unscrew the oil fill cap on the right side crankcase cover. This allows the oil to drain freely.
  4. Drain the Old Oil
    • Place your oil pan directly under the drain bolt.
    • With your socket wrench, remove the drain bolt located at the bottom of the engine.
    • Allow all old oil to fully drain. Wait a few minutes to ensure it drips out completely.
    • Remove the air bleed screw (located on or near the cylinder or filter cover) to help the oil drain more completely.
      Note:– The 1999 XT350 uses an air bleed screw, a detail not present on all dirt bikes. Remove it after loosening the drain bolt for more complete draining.
  5. Replace the Oil Filter
    • Locate the oil filter cover on the right side. It–s secured by three screws.
    • With your socket wrench, remove all three screws. Start with the lower screw to allow oil to drain from the cavity without spilling (specific to the XT350 line).
    • Cautiously remove the cover and the oil filter. Some oil may still leak out.
    • Clean the filter cavity. If using a reusable filter, clean with appropriate solvent and dry before reuse. If replacing, install your new filter now.
    • Carefully inspect the O-ring(s) on the filter cover. Replace if cracked, worn, or flattened. Ensure the new or reused O-ring sits securely.
  6. Reinstall Parts
    • Reinstall the oil filter cover; tighten the three screws evenly, starting with the lower one. Use a torque wrench to tighten to 10 Nm (7.2 ft-lb).
    • Reinstall the air bleed screw.
    • Reinstall the drain bolt. Torque it to 43 Nm (31 ft-lb). Do not overtighten;–overtightening is a common source of stripped threads on the XT350 case. If your crush washer or gasket is damaged, replace it to avoid leaks.
  7. Add New Oil
    • Set your funnel in the fill hole. Slowly add the recommended oil (1.3–1.4 liters, per above).
    • Replace the fill cap.
  8. Check Oil Level
    • Start the engine and let it run for about a minute, then shut off.
    • Allow a few minutes for the oil to settle.
    • With the bike held upright (not on the side stand), check through the oil level window on the lower right side crankcase cover.
    • The level should be centered between the max and min marks. If low, add a small amount of oil and recheck.
  9. Check for Leaks
    • Inspect the drain bolt, filter cover, and area under the engine for any oil leaks.

XT350-Specific Tips

  • Start with the lower oil filter cover screw when removing and reinstalling;–this prevents spills and aids drainage (unique to the XT350)
    “The oil filter cover is secured by three screws. The lower one should be removed first so that the filter cavity will drain.”
  • The air bleed screw aids oil drainage and air release after refill–always remember to remove and reinstall this (distinctive for this engine).
  • Do not overtighten the drain bolt or filter cover screws–stripping is a frequent issue on older Yamaha XT engines.
  • Use 10W40 or 20W40 oil depending on climate and riding conditions. Both weights are documented for this model range.
  • Always inspect the O-rings and replace as needed;–older rubber is prone to leaks after multiple changes.
  • Dispose of used oil and filter at a qualified recycling center.

MotoSport.com Pro Tip

  • Record your mileage and date of oil change in your maintenance log for future reference.
  • Yamaha recommends changing oil and filter at periodic intervals, check your owner–s manual for exact mileage hours.

Conclusion

A regular oil change is one of the best ways to prolong the life of your 1999 Yamaha XT350. By following this guide and using quality oil and filters, you–ll keep your XT350 running strong on the road or trail. For a complete line of OEM and aftermarket maintenance parts, shop with confidence at MotoSport.com.

Related Shopping Categories

Shop Motor Oil for a 1999 Yamaha XT350 Dirt Bike.

Shop Oil Filters for a 1999 Yamaha XT350 Dirt Bike.

Shop Oil Drain Pans for a 1999 Yamaha XT350 Dirt Bike.

Shop Tools for a 1999 Yamaha XT350 Dirt Bike.

Shop Oil Fillers and Drain Plugs for a 1999 Yamaha XT350 Dirt Bike.

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.