How to Change the Coolant in a 2019 Honda CRF150R Big Wheel
Shop parts for a 2019 Honda CRF150R Big Wheel Dirt Bike.
Your 2019 Honda CRF150R Big Wheel (often referred to as the CRF150RB) is a race-bred small-bore machine with a liquid-cooled engine and a unique chassis optimized for youth racers. Regular coolant changes protect your engine’s temperature stability, prevent corrosion, and enhance performance.
What You’ll Need
- Fresh, OEM-recommended coolant (Pro Honda HP Coolant or an equivalent high-quality motorcycle coolant is advised)
- Socket set and wrench
- Drain pan
- Shop rags
- Funnel
- Gloves and eye protection
Service Notes for the Big Wheel Model
- The CRF150RB fits larger wheels for increased ground clearance, but coolant service remains identical to the standard CRF150R.
- Radiator access is straightforward, but ensure your work area is clean to prevent debris from entering the cooling system.
- This model’s radiator is tightly packaged, so be methodical with bolt and cap removal.
Step-by-Step Coolant Change Guide
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Preparation
Make sure the engine is completely cool. Place the bike on a stable stand in a well-ventilated area. Remove the right side shroud (if needed) for improved radiator cap access. -
Drain the Old Coolant
Position a drain pan under the water pump. Locate the coolant drain bolt–usually on the lower water pump cover–and carefully loosen it with a socket wrench. Remove the radiator cap to allow full draining. Let the coolant empty completely.
Inspect the old coolant for debris or signs of corrosion, which can indicate other maintenance needs. -
Flush (Optional but Recommended)
If the coolant appears especially dirty, pour a small amount of distilled water into the radiator, replace the cap, and gently rock the bike to circulate the water. Drain again to remove as much residue as possible. -
Reinstall the Drain Bolt
Clean the drain bolt and its copper washer. Reinstall and tighten the bolt securely, but avoid over-tightening and damaging the threads. -
Refill with New Coolant
Using a funnel, fill the radiator with fresh coolant up to the filler neck. For the CRF150RB, the capacity is approximately 0.8 US quart (0.76 L). Always use manufacturer-specified coolant for the best corrosion protection and thermal performance. -
Bleed the System and Check for Leaks
Start the bike and let it idle with the radiator cap off (monitoring fluid level). Gently rev the engine several times to help purge air bubbles. As air escapes, you may need to add a little more coolant to top off. Watch for leaks at the drain bolt and hose connections. -
Final Steps
Once bubbling ceases and coolant level stabilizes, reinstall the radiator cap securely. Clean any spills with shop rags and reinstall the side shroud. Dispose of the old coolant appropriately–never pour it down drains or onto the ground.
Important Tips for 2019 CRF150RB Owners
- Never open the radiator cap when the engine is hot to prevent serious burns from hot coolant or steam.
- Inspect the radiator, hoses, and cap for cracks or leaks during every service–these parts are subject to wear due to off-road vibration.
- Always use non-silicate, motorcycle-specific coolant to avoid gel buildup that can clog small passages unique to high-rpm minibike engines.
- Check your coolant level frequently during race season or in hot climates, as this model’s small capacity makes it susceptible to quick losses from leaks or extreme use.
Routine coolant changes protect your CRF150RB's engine and keep you on track longer. For all the parts and maintenance supplies you need, Shop parts for a 2019 Honda CRF150R Big Wheel Dirt Bike.
Related Shopping Categories
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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.