How to Change the Oil in a 1987 Kawasaki KX80: Step-by-Step Guide
Shop parts for a 1987 Kawasaki KX80 Dirt Bike.
If you own a 1987 Kawasaki KX80, keeping your engine running smoothly means regular maintenance—especially changing the transmission oil. This guide provides proprietary, in-depth instructions for MotoSport.com readers looking to tackle their own preventative maintenance and keep their classic KX80 in top shape. We’ll cover all the tools you’ll need, the specific process for this 2-stroke mini-motocrosser, and highlight special notes unique to the 1987 model.
Tools and Supplies Needed
- Socket wrench set (including 17mm or 19mm for the drain plug, depending on model specifics)
- Torque wrench (to avoid overtightening the drain bolt)
- Drain pan or catch container
- Funnel
- Engine/transmission oil (quality 10W-40 or manufacturer-recommended two-stroke transmission oil; see your manual or AMSOIL's lookup page for compatibility)
- Rags or paper towels (for clean-up)
- Measuring cup (to pour the correct amount of oil–Kawasaki typically recommends around 700ml for similar two-stroke minibikes, but always verify for your exact model year)
- Gloves (optional but recommended for cleanliness)
Preparation and Safety
- Make sure your KX80 is on a stable, level surface and preferably on a stand.
- Work on the engine when it is cool to avoid burns, but if the bike hasn’t run in a while, you can idle it for a couple of minutes to warm the oil (it will drain better).
- Check behind and under the engine for any debris or old oil build-up before beginning.
Step-by-Step Oil Change Process for the 1987 Kawasaki KX80
-
Locate the Drain Plug:
- The drainage bolt is usually found at the bottom of the engine case, directly underneath the bike. Refer to your service manual for the exact location if unsure.
-
Place the Drain Pan:
- Position your oil catch container directly below the drain plug to catch used oil.
-
Remove the Fill Cap and Drain Plug:
- Remove the oil fill cap (on the side of the engine) to allow air in–aids in faster draining.
- Using your socket wrench, carefully loosen and remove the drain plug—do not lose the sealing washer if present.
- Allow all oil to fully drain out into your pan; this may take several minutes.
-
Inspect the Drained Oil:
- Check for metal flakes or discoloration. Metallic particles may indicate abnormal wear inside the engine. If present, consult a service professional before continuing.
-
Reinstall the Drain Plug:
- Clean the drain plug and washer, then thread the plug back in by hand to avoid cross-threading.
- Using your torque wrench, tighten the drain bolt to the manufacturer’s appropriate torque setting (refer to your 1987 KX80 service manual for the correct spec–avoid overtightening as this can strip the threads in the soft aluminum case).
-
Refill with New Oil:
- Using the measuring cup, measure the correct amount of transmission oil (generally about 700ml, but always check your exact owner’s manual or model chart to confirm for the 1987 KX80) .
- Insert the funnel into the fill hole and carefully pour in the new oil, avoiding spills on the engine or frame .
-
Check the Oil Level:
- With the bike upright (not on its side stand), verify the oil level is at the bottom of the fill threads or at the notched “full” indicator inside the fill hole (some bikes do not have a sight glass or dipstick and instead use the fill hole notch method) .
- Add oil slowly and check frequently to avoid overfilling. Never install more fluid than is adequate; overfilling can cause leaks and foaming .
-
Reinstall the Fill Cap:
- Firmly hand-tighten the fill cap. Double-check all fittings for leaks.
-
Test Run:
- Start the engine and let it idle for a few minutes, then shut off and re-verify oil level. Add a touch more if necessary, but do not exceed the correct quantity.
- Check again for leaks at both the drain and fill plugs.
-
Dispose of Used Oil:
- Properly dispose of used oil at your local recycling facility or auto parts store—never pour it down drains or into the yard.
Model-Specific Notes for the 1987 KX80
- The 1987 KX80 features a two-stroke engine with a separate transmission oil reservoir. NEVER add pre-mix or gasoline into the transmission oil fill port—this is exclusively for the gearbox, not for engine combustion.
- No oil filter to change: Unlike four-strokes or more modern bikes, the KX80 does not have an engine oil filter that requires periodic replacement. Just change the oil itself per your maintenance schedule .
- Tightening caution: The drain bolt threads in the KX80’s aluminum cases are soft. Overtightening is the most common mistake and will strip the threads, leading to expensive repairs. Always use a torque wrench and follow your manual’s specified torque value .
- Oil change interval: For competitive use, it’s recommended to change the transmission oil every few rides or races. At minimum, check before each use and change every 7–10 hours of riding .
- Fluid type: Use a quality two-stroke transmission oil or a manual gearbox type oil—consult your manual or recommendations from reputable sources (such as AMSOIL or Kawasaki documentation for the 1987 model) .
Final Tips and Best Practices
- Keep a log of your oil changes—date, hours, and oil type used—for best engine care.
- Always inspect drain and fill threads for damage before reinstalling fasteners.
- Clean up any spilled oil promptly to avoid slippery workspaces.
By following these steps and best practices, you’ll keep your vintage 1987 Kawasaki KX80 performing reliably for years to come. For more model-specific guides and expert dirt bike content, visit MotoSport.com—your one-stop resource for all things motocross.
Related Shopping Categories
Shop Motor Oil for a 1987 Kawasaki KX80 Dirt Bike.
Shop Oil Filters for a 1987 Kawasaki KX80 Dirt Bike.
Shop Oil Drain Pans for a 1987 Kawasaki KX80 Dirt Bike.
Shop Tools for a 1987 Kawasaki KX80 Dirt Bike.
Shop Oil Fillers and Drain Plugs for a 1987 Kawasaki KX80 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.