How to Change the Coolant in a 2000 Husqvarna CR50J Junior

Shop parts for a 2000 Husqvarna CR50J Junior Dirt Bike.

Routine coolant changes are vital to keep your 2000 Husqvarna CR50J Junior running cool and performing at its best. This single-speed, air-cooled mini racer boasts fundamental simplicity, but proper cooling is key to long-term reliability and power output–especially when learning young riders are pushing its limits. Here is MotoSport.com's step-by-step proprietary guide to changing the coolant on the CR50J Junior.

What You'll Need

  • Fresh, brand-appropriate coolant (never mix coolant types)
  • Basic metric hand tools (sockets, screwdrivers)
  • Drain pan or bucket
  • Distilled water (for flushing, if needed)
  • Shop rags
  • Safety gloves and eyewear

Step 1 – Prep Your Workspace and Bike

  • Let the engine cool fully before working on the cooling system to prevent burns or injury.
  • Position the CR50J securely on a stand to keep it upright and level. This ensures thorough draining and the proper coolant fill level.

Step 2 – Access and Drain the Coolant

  • Locate the radiator drain bolt, typically found at the base or lower side of the radiator, or the water pump cover drain bolt on the right side of the engine.
  • Position your drain pan beneath the drain bolt or hose.
  • Slowly remove the radiator cap (if equipped) to release pressure and allow air in, then loosen the drain bolt or disconnect the lower radiator hose. Allow all old coolant to drain completely.
  • If you have a coolant overflow or expansion tank, disconnect and drain this as well, rinsing with distilled water if contamination or buildup is evident.

Step 3 – Flush the Cooling System (if needed)

  • If you are switching coolant types or notice dirty fluid, flush the system: Reinstall the drain bolt, fill the radiator with distilled water, run the engine briefly (one to two minutes), then drain again. Repeat until clear water drains out.
  • Inspect hoses and clamps for cracks or brittleness–replace as needed for safe riding.

Step 4 – Reinstall and Tighten All Fasteners

  • Ensure the drain bolt is clean and reinstalled. Tighten all hose clamps and bolts to firm, but not overtight, to avoid damage.
  • Double-check hose routing and clamps for security–on the CR50J Junior's compact chassis, even a small clamp out of place can lead to leaks.

Step 5 – Add New Coolant

  • Pour fresh coolant into the radiator fill neck, slowly and steadily, to minimize trapped air bubbles. Fill until coolant reaches the base of the filler neck.
  • For models with an overflow bottle, fill to the appropriate level line marked on the tank.
  • Do not mix incompatible coolants; choose a quality, pre-mixed dirt bike coolant for best protection.

Step 6 – Bleed Air from the System

  • Rock the bike gently and squeeze the hoses to help dislodge trapped air.
  • Start the engine and let it idle with the radiator cap OFF. After the coolant level drops (as the air purges), top off again as needed.
  • Once no more bubbles appear, install the cap. Allow the engine to run until it heats up, then cool fully. Recheck and top off the coolant level–this final step prevents air pockets from causing overheating.

Step 7 – Inspect and Clean Up

  • Wipe down any spills with a rag and water–coolant is slippery and toxic to pets.
  • Verify that no leaks are present at any connection or joint.
  • Check the radiator shroud and guards for clear airflow before your next ride.

CR50J Junior Owner Notes

  • The CR50J Junior uses a compact, race-focused cooling system. Proper coolant maintenance prevents seized engines and warped heads in these high-RPM minis.
  • Always allow the system to vent air–small radiators are less tolerant of trapped air bubbles than larger systems.
  • If you notice overheating or recurring fluid loss, inspect for hidden leaks or possible head gasket issues–rare, but possible after hard use.

Changing the coolant is a routine service that pays off in long-lasting reliability, safe riding, and maximum power for every lap. MotoSport.com is your destination for OEM & aftermarket parts for the 2000 Husqvarna CR50J Junior, ensuring every service job is done with the right equipment for peak performance.

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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.