DMR-Japan Rotemp Thermostat Kit – Honda NS400R (NC19)

Improve the cooling performance of your Honda NS400R with the DMR-Japan Rotemp Thermostat Kit. Designed to begin opening at a lower temperature than the factory thermostat, this genuine DMR-Japan upgrade helps reduce engine operating temperatures and maintain more consistent performance.

Ideal for spirited road riding, track use, and high-performance engine builds, the Rotemp thermostat allows coolant to circulate through the radiator earlier, helping prevent excessive heat build-up and the power loss associated with high coolant temperatures.

Features

• Genuine DMR-Japan original product
• Lower opening temperature than the OEM thermostat
• Helps reduce engine operating temperatures
• Promotes earlier coolant circulation
• Supports more consistent engine performance
• Direct replacement for the factory thermostat
• Includes new O-rings for installation

Valve Opening Temperature

• OEM Thermostat: 65°C
• DMR-Japan Rotemp Thermostat: 60°C

Kit Includes

• 1 × Rotemp Thermostat
• 1 × Thermostat Cover O-Ring
• 1 × Thermostat Housing O-Ring

Benefits

The Rotemp thermostat begins circulating coolant sooner than the factory unit, helping to:

• Reduce coolant temperature during hard riding
• Minimise heat soak
• Improve cooling efficiency
• Help maintain engine performance
• Reduce power loss caused by excessive engine temperatures

As engine temperatures rise, intake air becomes hotter and less dense, reducing the amount of oxygen available for combustion. By helping to control coolant temperature, the Rotemp thermostat assists in maintaining more consistent engine performance.

For high-performance two-stroke engines, coolant temperatures in the 50–60°C range are often considered ideal, making the Rotemp thermostat an excellent upgrade for restored, modified, or enthusiast-owned NS400Rs.

Fitment

• Honda NS400R (NC19)

Important Information

• Product specifications may change without prior notice from the manufacturer.
• Any instructions supplied with this product are likely to be in Japanese.
• Professional installation is recommended, and coolant should always be replaced and bled correctly after installation.

Keep your legendary Honda NS400R running cooler with the DMR-Japan Rotemp Thermostat Kit—a simple yet effective upgrade for improved cooling performance and consistent engine operation.