How to Change the Oil in a 1987 Honda CR125: Step-By-Step Guide
Shop parts for a 1987 Honda CR125 Dirt Bike.
Keeping your 1987 Honda CR125 running smoothly depends on regular maintenance, and changing the transmission oil is a crucial part of that. This guide will walk you through everything you need for a successful oil change, with special call-outs relevant to the CR125's make and model. All instructions are proprietary to MotoSport.com.
Tools and Materials Needed
- 17mm socket or wrench (for drain bolt)
- Drain pan (to collect used oil)
- New sealing washer (replace every oil change)
- Rag or paper towels (for clean-up)
- Engine stand or triangle stand (to support the bike upright)
- Recommended oil: Pro Honda HP2 2-stroke oil (32:1 mix), or equivalent one for transmissions
- Socket wrench or T-handle
- Torque wrench (optional but ideal for factory spec tightening)
- Funnel (for pouring fresh oil)
- Gloves (to keep your hands clean)
- Screwdriver (if required for filler cap)
Step-by-Step Process
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Warm up the engine:
- Start your CR125 and let it idle for 1–2 minutes. Warm oil drains more easily and helps flush out contaminants.
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Support the bike:
- Secure your bike on a triangle or engine stand so it remains upright on a level surface. This ensures a complete drain and accurate fill.
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Remove the oil filler cap:
- Locate the filler cap on the right crankcase cover. Unscrew and set aside. This allows air in, helping oil drain fully.
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Position the drain pan:
- Slide a drain pan directly beneath the engine to catch old oil.
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Remove the drain bolt:
- Locate the 17mm drain bolt on the bottom side of the engine case. Use a socket or wrench to loosen and carefully remove it. Be cautious—oil may be hot. Allow oil to drain completely.
- Be sure to catch and remove the old sealing washer.
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Inspect and install a new sealing washer:
- Always replace the drain bolt washer with a new one to prevent leaks.
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Reinstall and tighten the drain bolt:
- Thread the drain bolt and new washer by hand to avoid cross-threading, then tighten with your wrench.
- Factory torque specification: 21 lbf·ft (29 N·m) for the drain bolt. Over-tightening can damage the aluminum case.
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Add fresh oil:
- Using a funnel, add recommended oil. For a 1987 CR125, capacity is 0.60 US quarts (approx. 0.57 liters) at oil change. Always double-check your manual for confirmation.
- Slowly pour in oil until it reaches the base of the filler threads or specified mark.
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Check oil level:
- Some models have a check bolt on the engine side—slightly open it. Oil should seep out when the level is correct. If not, add more oil gradually.
- If no check bolt, ensure oil is just to the bottom of the filler hole with the bike level.
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Install the filler cap:
- Screw on the filler cap tightly by hand.
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Dispose of old oil properly:
- Collect old oil in a sealed container and dispose of at an approved recycling facility. Do not pour it on the ground or down drains.
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Final inspection and clean up:
- Wipe down any spills, check for leaks under the drain bolt and filler cap after starting the engine for a minute or two.
Model-Specific CR125 Call-Outs (1987)
- Older CR125 models like the 1987 do not have a transmission oil filter. Thus, complete draining and regular oil changes are critical for clutch longevity.
- Always replace the sealing washer on the drain bolt to avoid case damage or leaks—this is especially crucial on older Honda cases that are prone to strip threads if over-tightened.
- Use only non-friction-modified oil formulated for 2-stroke transmissions (do not use standard engine oil or gear oil for cars).
- Overfilling can result in poor clutch release or shifting issues; underfilling can cause rapid gear wear.
- Do not confuse the transmission oil cavity (what you service here) with the premix oil that lubricates the crankshaft bearings via the fuel on 2-stroke engines.
Conclusion
Changing the oil on your 1987 Honda CR125 is straightforward when following these steps. With the right tools and attention to model-specific details, you’ll keep your dirt bike in top shape and ready for the next ride. For more OEM parts or replacement fluids, trust MotoSport.com for reliable service and expert support.
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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.