How to Change the Coolant in a 1977 Yamaha IT250: MotoSport Owner's Guide
Shop parts for a 1977 Yamaha IT250 Dirt Bike.
Swapping the coolant on your vintage 1977 Yamaha IT250 is essential maintenance for keeping the two-stroke engine running cool and reliably. Unlike more modern bikes, the original IT250 uses an air-cooled system—meaning there's no liquid coolant or radiator to flush. However, if your bike has an aftermarket or retrofitted liquid-cooling kit (not uncommon in heavily modded vintage IT series), the following guide covers the steps, along with key model-specific notes for IT250 owners.
What You Need to Know About the 1977 IT250 Cooling System
- Stock Configuration: The 1977 IT250 is air-cooled from the factory. No regular liquid coolant changes are needed for a stock bike—routine maintenance involves cleaning fins, checking for debris, and monitoring for overheating.
- Modified Models: If aftermarket liquid cooling has been installed, follow the coolant service steps below. Verify which system you have before proceeding. Never attempt to add liquid coolant to an original, unmodified air-cooled machine.
How to Change Coolant in a Liquid-Cooled IT250 (Aftermarket Systems)
- Preparation
- Allow the bike to cool completely before beginning work to avoid burns.
- Place the bike on a stable stand.
- Gather tools: socket set, gloves, drain pan, funnel, and new coolant (use premixed motorcycle coolant or a 50/50 mix of coolant and distilled water for ideal corrosion protection).
- Drain Old Coolant
- Locate the radiator drain bolt (commonly on the lower edge of the radiator or engine water pump cover in retrofit kits).
- Remove the radiator cap (if equipped) to help coolant flow out smoothly.
- Place the drain pan beneath the bolt, unscrew it, and let coolant drain fully.
- If your system includes a coolant reservoir, drain it as well.
- Optional: Flush the System
- For neglected systems, flush using a 50/50 mix of distilled water and white vinegar.
- Fill and run the engine briefly, then let it cool and drain the mix.
- Follow with a flush of plain distilled water, then drain again.
- Check manual or consult your mechanic if unsure about flushing—some retrofits may use unique materials.
- Refill with Fresh Coolant
- Install a new sealing washer on the drain bolt, retighten bolt to spec.
- Using a funnel, slowly pour new coolant into the radiator until the filler neck is full.
- If equipped, fill the overflow reservoir to the indicated level.
- Burp the System
- Start the bike and let it idle with the radiator cap off (if safe), gently rocking the bike and squeezing coolant hoses to release trapped air bubbles.
- Watch for coolant level drop; top off if necessary.
- Once at operating temperature, shut off the bike and allow it to cool. Top up again if the level has dropped.
- Final Steps
- Reinstall radiator cap and check for leaks.
- Inspect the system after your first ride, topping off as needed.
- Ensure proper disposal of old coolant – never pour it down drains or onto the ground.
Model-Specific Tips for 1977 Yamaha IT250 Owners
- Original air-cooled fins are critical to cooling efficiency. Keep them clear of mud and damage.
- If you spot oil leaks near the head or base gasket, address them immediately; leaking oil can compromise fin cooling.
- Aftermarket cooling modifications should always be double-checked for leaks, proper hose routing, and stable mounting before riding hard off-road.
- Because the IT250 is vintage, check all rubber hoses and clamps for age-related cracks if running a liquid system. Replace any suspect parts with modern equivalents.
Routine maintenance keeps your IT250 adventure-ready, whether in air- or liquid-cooled form. If you need replacement hoses, radiators, gaskets, or simply want genuine hardware upgrades, Shop parts for a 1977 Yamaha IT250 Dirt Bike.
Related Shopping Categories
Shop Radiators for a 1977 Yamaha IT250 Dirt Bike.
Shop Coolant for a 1977 Yamaha IT250 Dirt Bike.
Shop Temperature Sensors for a 1977 Yamaha IT250 Dirt Bike.
Shop Tools for a 1977 Yamaha IT250 Dirt Bike.
Shop Radiator Hoses for a 1977 Yamaha IT250 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.