How to Change the Oil in a 1991 Suzuki DR650S

Shop parts for a 1991 Suzuki DR650S Dirt Bike.

Changing the oil in your 1991 Suzuki DR650S is essential for keeping your engine healthy and ensuring top performance on the trail or street. This guide, proprietary to MotoSport.com, provides step-by-step instructions tailored to the unique details of the early DR650S models. You'll find a complete list of required tools, detailed procedures, and special call-outs specific to the 1991 DR650S. Performing regular oil changes not only increases the longevity of your engine but also preserves the value of your motorcycle.

Tools and Supplies Needed

  • 17 mm socket and ratchet (for drain bolt)
  • 8 mm socket and ratchet (for oil filter cover bolts)
  • Oil drain pan
  • New oil filter
  • New drain plug washer (crush washer)
  • New oil filter O-rings (highly recommended)
  • Funnel
  • 2.1 – 2.3 quarts (2,000–2,150 ml) of 10W-40 motorcycle oil (API SE or SF)
  • Clean rags or shop towels
  • Contact cleaner (optional, for cleaning residues)
  • Torque wrench (recommended for proper tightening)

Specific Call-Outs for the 1991 Suzuki DR650S

  • The 1991 DR650S engine oil capacity is approximately 2,000 ml (2.1 US quarts) without filter change, 2,150 ml (2.3 US quarts) with filter change. Always verify with your dipstick or sight glass after filling.
  • Earlier DR650S models have similar oil change procedures as DR650s from later years, but always check that O-rings and filter springs are correctly seated to avoid leaks or oil starvation.
  • Do not over-torque the oil filter bolts; these are easy to strip in the aluminum engine block—tighten to factory specs (about 7 ft-lb for O-ring cover bolts, 17.5 ft-lb for drain bolt).

Step-by-Step Instructions

  1. Warm Up the Engine
    • Start the DR650S and let it idle for 2-3 minutes. This warms the oil so it flows better and suspends contaminants. Shut off the bike and allow it to rest for a few minutes.
  2. Prepare Your Work Area
    • Park the bike upright on a stand or level ground. Place the oil drain pan beneath the engine drain plug. Lay out all your tools and supplies ahead of time.
    • If you have a skid plate, you may need to remove it to access the drain bolt.
  3. Remove the Fill Plug
    • This allows air in so the oil drains faster. Clean the area around the filler with a rag to prevent debris from entering the engine, then remove the fill cap located on the engine case.
  4. Drain the Old Oil
    • Use a 17 mm socket and ratchet to remove the oil drain bolt at the bottom of the engine. Be careful: the oil may be hot.
    • Allow all oil to drain completely. Inspect the drain plug and—as a best practice—replace the crush washer with a new one.
    • Clean the drain bolt. Once oil has fully drained, re-install the drain bolt and tighten to 17.5 ft-lb (24 Nm); avoid overtightening to protect the threads.
  5. Remove and Replace the Oil Filter
    • Clean around the oil filter cover with contact cleaner and a rag. Remove the cover bolts (8 mm socket). Note the orientation of the oil filter and the spring configuration.
    • Remove the old oil filter. Check the oil filter cap for O-rings—replace both with new ones if available.
    • Lightly coat new O-rings with fresh oil before installation to improve sealing and longevity.
    • Reinstall the spring, insert the new filter, reinstall the cover, and tighten bolts evenly to 7 ft-lb (10 Nm) to prevent damage to the cover or the O-rings.
  6. Add New Oil
    • Using a funnel, pour in 2.1 – 2.3 quarts (2,000–2,150 ml) of high-quality 10W-40 motorcycle oil (API SE or SF grade).
    • Reinstall and hand tighten the oil filler cap.
  7. Run the Engine and Check Oil Level
    • Start the bike and let it idle for a few minutes. Shut it down and wait five minutes for the oil to settle.
    • Check the oil level with the inspection window or dipstick. The oil should be at the "F" (full) mark. Add oil as needed.
  8. Check for Leaks and Finish Up
    • Inspect the drain bolt and oil filter cover for leaks. Clean up any spills and properly dispose of the used oil and filter at a recycling facility.
    • Record your mileage and date to stay on schedule for your next change (recommended every 4,000 miles or 12 months).

Pro Tips for 1991 DR650S Owners

  • Always confirm both the O-ring and spring are installed with the new filter or severe engine damage may result.
  • The aluminum threads in the engine case are soft—use a torque wrench for filter cover and drain bolt bolts whenever possible.
  • If you notice recurring oil leaks at the filter cover, replace both O-rings and ensure the filter spring isn’t lost or installed incorrectly.
  • Consider upgrading to a magnetic drain plug for improved engine protection and easier monitoring of engine wear.
  • Never overtighten the drain plug or oil filter cover bolts—these can strip easily on early ’90s DR650S engines.

Changing the oil yourself saves money and extends the life of your 1991 Suzuki DR650S. Following these proprietary MotoSport.com steps ensures a reliable, leak-free oil change every time.

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Shop Oil Fillers and Drain Plugs for a 1991 Suzuki DR650S 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.