How to Change the Coolant in a 2001 Husqvarna CR50J Junior

Shop parts for a 2001 Husqvarna CR50J Junior Dirt Bike.

Changing the coolant in your 2001 Husqvarna CR50J Junior is an important part of regular maintenance, especially for a liquid-cooled race bike designed for junior riders. Proper coolant replacement helps protect the engine from overheating and corrosion – key to ensuring this youth-focused race bike runs at peak performance.

What Makes the 2001 CR50J Junior Unique?

The CR50J Junior features a liquid-cooled 50cc two-stroke engine with yellow shrouds and a performance-focused chassis. This model stands out with its advanced suspension compared to other youth dirt bikes, offering enhanced handling and more power designed to help young riders step up their performance*. Regular coolant changes are vital to maximize the lifespan and power of this high-revving, liquid-cooled engine*.

What You Need

  • High-quality coolant suitable for two-stroke, liquid-cooled engines (refer to manufacturer recommendations)
  • Drain pan
  • Phillips screwdriver and metric sockets
  • Clean rags
  • Funnel
  • Protective gloves

Step-by-Step Guide

  1. Ensure the Engine is Cool
    Never attempt to drain or open the radiator cap while the engine is hot. Let the bike cool fully.
  2. Remove Shrouds if Needed
    Using a Phillips screwdriver or socket, remove the plastic radiator shrouds if needed for better access. The 2001 CR50J Junior uses yellow shrouds.
  3. Locate the Radiator Cap and Drain Bolt
    Find the radiator cap (typically on top of the left or right radiator) and the radiator drain bolt (often located at the bottom corner of the radiator or on the water pump housing).
  4. Drain Old Coolant
    Place a drain pan underneath the drain bolt area. Remove the radiator cap. Then, unscrew the drain bolt and allow the coolant to fully empty into the pan. Remove any bleed screws to help air and coolant exit fully.
  5. Inspect the System
    While draining, inspect hoses, clamps, and the radiator itself for leaks or damage. The liquid-cooled setup on this bike is performance tuned; check for any obstructions in the flow.
  6. Flush (Optional but Recommended)
    If the old coolant appears dirty or contaminated, flush the system with clean distilled water, running it briefly (with radiator cap off), then drain. Repeat until clear.
  7. Reinstall Drain Bolt
    Replace the drain bolt and any bleed screws, tightening them securely. Always use a new washer or O-ring if required.
  8. Refill Coolant
    Using a funnel, pour new coolant into the radiator slowly, filling up to the recommended level (refer to your service manual for exact capacity, typically around 500-650 ml for a small engine like this). Squeeze coolant hoses gently to help air escape.
  9. Check for Air Pockets
    Rock the bike gently and squeeze the hoses to help work out trapped air. Top off coolant if needed.
  10. Run and Check
    Start the engine, let it idle briefly, then shut off and recheck the coolant level. Add more if necessary to reach the full mark. Replace the radiator cap securely and reinstall the shrouds if removed.

Tips Specific to the CR50J Junior

  • Always use high-quality, motorcycle-specific coolant. This model relies on efficient cooling to maintain its two-stroke performance characteristics.
  • Monitor coolant level frequently. The small radiator volume makes it sensitive to even minor leaks or evaporation.
  • Do not overfill. Overfilling can lead to overflow and reduced cooling performance on extended rides and races.

Final Inspection

  • Rinse off any spilled coolant and ensure all shroud bolts are tight.
  • Take a short test ride and monitor temperature. Any signs of overheating or leaking should be addressed immediately.

Sticking to regular maintenance helps the Husqvarna CR50J Junior deliver reliable power and fun, keeping young riders safe and competitive. If you need replacement parts, hoses, or new coolant, MotoSport has you covered.

*Based on collected model information and typical maintenance requirements for liquid-cooled youth motocross motorcycles.

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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.