How to change the oil in a 1986 Yamaha XT350 Dirt Bike

How to Change the Oil in a 1986 Yamaha XT350: A Complete Step-by-Step Guide

Shop parts for a 1986 Yamaha XT350 Dirt Bike.

A well-maintained Yamaha XT350 delivers years of rugged reliability, and routine oil changes are vital to keeping this legendary dual-sport running smoothly. This exclusive MotoSport.com guide walks you through the process, highlights model-specific tips, and lists the tools you’ll need for the job.

Tools and Materials Required

• SAE 10W-40 or 20W-40 motorcycle engine oil (see manual for exact recommendation)
• Oil filter (Yamaha genuine or quality equivalent, part number as needed for the XT350)
• Replacement O-rings (optional, but inspect for wear and leaks)
• Socket wrench set (with appropriate sockets for drain bolt and filter cover screws)
• Torque wrench (for precise bolt tightening)
• Drain pan
• Shop rags
• Small funnel
• Solvent (for cleaning oil filter, if reusing the element)

Step 1: Preparation

• With the engine off, place your XT350 securely on a level surface. Using a center stand or paddock stand is ideal for stability.
• Warm up the engine for a few minutes. This helps the oil flow and carries debris with it, making draining more effective. Do not let the engine get overly hot—just warm to the touch.
• Switch off the engine and allow it to cool slightly so it’s safe to handle.

Step 2: Draining the Old Oil

• Place your drain pan under the engine to catch used oil. On the XT350, the drain bolt is located under the engine crankcase.
• Remove the oil filler cap to vent the system and allow oil to drain more freely.
• Using your socket wrench, remove the drain bolt. Allow oil to drain completely.
• Remove the oil filter cover screws (there are three; remove the lower one first so the filter cavity drains smoothly) and take off the oil filter cover. Be careful not to lose the O-ring.
• Inspect the crush washer or O-ring on the drain bolt and the O-ring on the filter cover. Replace if damaged or flattened.

Step 3: Replacing the Oil Filter

• Remove the oil filter element from its seat.
• If you’re reusing the filter, clean it with solvent; otherwise, install a new filter of the proper spec for the XT350.
• Make sure the O-ring is properly seated on the filter cover before reinstalling. This helps prevent leaks.
• Reinstall the filter cover and screws. Use a torque wrench to tighten the filter cover screws to 10 Nm (7.2 ft-lb).
• Reinstall the drain bolt and tighten to 43 Nm (31 ft-lb).

Step 4: Refilling with New Oil

• Use a funnel to add new oil through the filler hole. The 1986 XT350 takes approximately 1.3 L (1.34 US qt) for just an oil change, or 1.4 L if the oil filter is replaced according to Yamaha’s service data.
• Make sure you are using the recommended oil: SAE 10W-40 or SAE 20W-40, type SE or better.

Step 5: Bleed and Prime (XT350-Specific Call-Out)

• The XT350 has an oil system air bleed bolt on the cylinder head cover. After changing the filter, you should bleed air from the system to prime the oil pump and ensure full lubrication on startup.
• With the filter installed, remove the bleed bolt and, with the kill switch OFF, crank the engine several times (using the starter or kickstarter with decompression lever pulled). Watch for oil to come from the bleed port.
• When oil emerges without bubbles, reinstall and torque the bleed bolt. This step helps prevent oil starvation on initial startup.

Step 6: Check the Oil Level

• Start the engine and let it run for a minute, then turn off and let the oil settle for several minutes.
• Check the oil level through the sight window low on the right side of the crankcase.
• The level should be between the minimum and maximum marks. Add oil if needed, being careful not to overfill.

Step 7: Final Inspection

• Check for leaks around the drain bolt and oil filter cover.
• Safely dispose of your used engine oil and oil filter according to your local regulations.

Important XT350-Specific Notes

• The XT350 air-cooled engine relies heavily on oil flow for temperature and lubrication control–bleeding the system after a filter change is crucial.
• Correct torque on all fasteners is important to prevent oil leaks or stripped threads—avoid overtightening aluminum parts.
• The oil system is fairly robust, but running the engine with low oil can cause rapid engine wear. Always check the level after each service.
• If the oil warning lamp fails to go out after bleeding/priming, do not ride; repeat the bleeding procedure.

Remember, proper oil and filter changes maximize your Yamaha XT350’s life and performance—ride confidently, knowing your engine is well protected.

This proprietary content was provided by MotoSport.com for Yamaha XT350 owners and may not be reproduced without permission.

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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.