How to Change the Oil in a 1990 Suzuki DR350: The Complete Guide
Shop parts for a 1990 Suzuki DR350 Dirt Bike.
Regularly changing the oil in your 1990 Suzuki DR350 is key to maintaining peak performance and longevity for your dual-sport motorcycle. The DR350 uses a dry-sump oiling system, storing oil in both the crankcase and the frame. This guide, proprietary to MotoSport.com, details every essential step, including tips unique to the DR350. The process is straightforward, but a few quirks set this bike apart from other dirt bikes—pay close attention to the call-outs for your specific year and model.
Tools and Materials Needed
- 10mm, 12mm, 14mm, 17mm, and 19mm wrenches or sockets
- Socket wrench/ratchet
- Oil catch pan
- Replacement oil filter (OEM or quality aftermarket)
- New crush washers for drain bolts (recommended)
- Phillips or flathead screwdriver
- Needle-nose pliers (optional for hose clamps and spring clips)
- Rags or shop towels
- 2 quarts of 10W-40 motorcycle oil (consult manual for oil capacity)
- Funnel
- Box of disposable gloves
Preparation and Safety
- Warm the engine for 2-3 minutes. This helps oil drain more thoroughly.
- Ensure the bike is stable, using a center stand or secure lift.
- Wear gloves and ensure the work area is well-ventilated.
Step-By-Step Instructions
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Remove the Skid Plate (If Doing a Complete Change):
- The DR350 frame contains the oil and an oil screen, accessible only when the skid plate is off. Use a 12mm wrench to remove the four mounting bolts–two in the front, one on each side. Set them aside.
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Drain the Engine Oil:
- Locate the crankcase drain plug underneath the engine. Use a 14mm socket or wrench. Place the oil pan directly below.
- Carefully loosen and remove the plug. Allow oil to drain completely.
- Inspect and replace the crush washer if needed to ensure a good seal.
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Drain the Frame (Dry Sump) Oil:
- Find the frame's oil drain bolt, typically on the front lower frame or down tube–use a 12mm wrench.
- Remove it and allow oil to drain fully from the oil reservoir in the frame.
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Remove and Inspect the Oil Screen (Optional but Recommended):
- The DR350 has a screen filter in the frame to catch larger debris and particles. Access it after the frame's oil is drained.
- Remove the screen with pliers or your fingers. Clean it with solvent or fresh oil. Reinstall securely before proceeding.
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Replace the Oil Filter:
- The oil filter is typically on the right side of the engine. Use an 8mm/10mm wrench to remove the cover bolts.
- Remove the old filter. Clean the filter housing. Install the new filter.
- Ensure the filter spring is properly in place. Install a new gasket or sealing ring if necessary.
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Reinstall Everything:
- Reinstall frame and crankcase drain bolts with fresh crush washers (prevents leaks).
- If you removed the skid plate, reinstall and tighten all four bolts.
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Refill with Fresh Oil:
- Using a funnel, add approximately 2 quarts of 10W-40 motorcycle oil into the oil fill–the filler is typically located atop the frame near the steering head or next to the engine, depending on sub-model.
- Stop periodically to check the oil level–DO NOT overfill. Check for leaks at all drain bolt locations.
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Distribute Oil Through the System:
- Turn the ignition off. Slowly kick the engine over 5-10 times (without starting) to help prime oil throughout the engine passages and frame lines, as per DR350 guidance.
- Start the engine and let it idle for 60 seconds. Shut off, allow to settle for a couple of minutes, check, and top off oil to the correct level via the sight glass or dipstick.
Specific DR350 Call-Outs and Tips
- Oil-in-frame design: Unlike many bikes, oil is stored in both the frame and engine. Always drain both for a full oil change. Skipping the frame side leaves old oil and debris in the system.
- Check the oil screen periodically. It's a unique feature to the DR350 dry-sump setup and helps protect your engine from more serious contamination.
- Crush washers: Always use a new crush washer on both the crankcase and frame drain bolts to prevent oil leaks.
- Oil quantity: The 1990 DR350 may require slightly less oil than later models (approximately 1.5 to 2 quarts); always refer to your owner's manual for precise capacity.
- Tightening torque: Don't overtighten drain bolts or filter cover bolts–the aluminum threads in old bikes are easy to strip.
- Oil type: Only use motorcycle-specific 10W-40 oil (not automotive oil), as these bikes use wet clutches. Non-motorcycle oil can cause clutch slippage.
Final Steps and Inspection
- Inspect all bolts and gaskets for integrity and leaks after the bike cools post oil-change ride.
- Properly dispose of old oil and filter at a certified recycling center.
By following this guide, you ensure your 1990 Suzuki DR350 continues to deliver the performance, reliability, and trail-ready ruggedness it's known for. For OEM and aftermarket oil filters, crush washers, tools and quality motorcycle oil, shop MotoSport.com for everything you need to keep your DR350 running strong.
Related Shopping Categories
Shop Motor Oil for a 1990 Suzuki DR350 Dirt Bike.
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Shop Oil Drain Pans for a 1990 Suzuki DR350 Dirt Bike.
Shop Tools for a 1990 Suzuki DR350 Dirt Bike.
Shop Oil Fillers and Drain Plugs for a 1990 Suzuki DR350 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.