Description

The NGage VH8RTII-9 Double Iridium Spark Plug is a precision ignition component developed for modern, fuel-injected motorcycles, including the Triumph Speed 400, Scrambler 400X, and Speed T4. Manufactured in Japan, this spark plug is part of NGage’s Double Iridium series and is specified for use in both BS4 and BS6 compliant motorcycles, as stated by the manufacturer.

This listing focuses exclusively on its application for Triumph’s 400-class single-cylinder platform, where the VH8RTII-9 spark plug specification is listed by NGage in its official compatibility chart. It is intended as a direct replacement spark plug for these motorcycles, without modification.

Designed for Triumph 400-Class Motorcycles

Triumph’s 400-class motorcycles represent a new-generation, liquid-cooled, fuel-injected single-cylinder engine platform developed for modern combustion and emission standards. NGage specifies the VH8RTII-9 spark plug for this engine family, indicating alignment with the ignition system design and operating parameters of these motorcycles.

The following Triumph models are listed by NGage for use with the VH8RTII-9 spark plug:

• Triumph Speed 400

• Triumph Scrambler 400X

• Triumph Speed T4

For these motorcycles, the VH8RTII-9 is intended to function as a like-for-like replacement for the factory-specified spark plug type. It is not positioned as a tuning component or a modification-driven upgrade, but as a specification-correct ignition part for routine service or replacement.

Double Iridium Spark Plug Construction

NGage classifies the VH8RTII-9 as a Double Iridium spark plug, meaning iridium material is used on both the center electrode and the ground electrode.

Iridium is used in modern spark plug construction due to its high melting point and resistance to electrode erosion during repeated ignition cycles. This construction approach is commonly applied in motorcycles with high-energy ignition systems and tightly controlled combustion environments.

The double-iridium configuration is intended to maintain consistent electrode geometry over extended operating periods under normal riding conditions. NGage does not publish electrode dimensions, spark-gap values, heat-range explanations, or service-interval figures for this model.

BS4 and BS6 Compatibility

NGage specifies that the VH8RTII-9 spark plug is compatible with both BS4 and BS6 vehicles. This makes it suitable for use across production years that fall before and after the BS6 emission-standard transition, provided the motorcycle is included in the compatibility list.

For Triumph’s 400-class motorcycles, this ensures suitability across emission-compliant variants without requiring a change in spark plug specification.

No emission-reduction, fuel-efficiency, or tuning claims are made for this product.

Manufacturing Origin

The VH8RTII-9 spark plug is manufactured in Japan, as stated on NGage’s product packaging.

NGage does not publish further information regarding production processes, certifications, or testing standards for this model. The country of manufacture is provided here as factual product information only.

Intended Use

The NGage VH8RTII-9 is intended for routine replacement during scheduled maintenance or spark-plug service intervals recommended by the motorcycle manufacturer. It is suitable for everyday road use on the Triumph Speed 400, Scrambler 400X, and Speed T4 within standard operating conditions.

This spark plug is not positioned by NGage as a racing-only, track-specific, or specialized tuning component.

Fitment Accuracy

Correct spark plug selection is critical for engine operation and long-term reliability.

The VH8RTII-9 should be installed only on motorcycles listed in the compatibility section below. Use on non-listed motorcycles is not recommended.

For the Triumph 400-class motorcycles, this spark plug is specified by NGage as the correct application for this engine platform.

Compatibility

As per NGage official compatibility chart for part number VH8RTII-9:

Triumph Motorcycles

• Triumph Speed 400

• Triumph Scrambler 400X

• Triumph Speed T4

Variant Explanation

This listing is for NGage VH8RTII-9 Double Iridium Spark Plug only.

• “Double Iridium” refers to iridium usage on both the center and ground electrodes.

• This part number represents a single manufacturer-defined specification.

• No alternate heat ranges or material variants are included in this listing.

Specifications (Only Verified Data)

• Brand: NGage

• Part Number: VH8RTII-9

• Spark Plug Type: Double Iridium

• Vehicle Compatibility: BS4 & BS6

• Country of Manufacture: Japan

• Application: Motorcycle spark plug

Installation / Usage Notes

• Install only on Triumph motorcycles listed in the compatibility section.

• Follow Triumph service-manual torque specifications.

• Install on a cold engine.

• Install as per the motorcycle manufacturer’s service manual torque specification and standard spark plug installation procedure.

Specifications

Pros and cons

• Double iridium electrode construction designed for modern fuel-injected ignition systems
• Manufacturer-listed compatibility with Triumph Speed 400, Scrambler 400X,
• Speed T4
• Direct replacement specification for the listed Triumph applications
• Intended for standard replacement use rather than custom ignition tuning
• Supplied as a single spark plug