This support tool Motone allows you to modify the original headlight/tool support.
The Street TwinTriumph is designed with a single support that holds both the front headlight and the instrumentation. If you want to modify the headlight support with something more minimal, you will need to use a support like this one from Motone to keep the speedometer securely attached to the motorcycle.
The headlight support for Triumph from motone is made of reinforced die-cast aluminum to prevent vibrations from being transmitted to the engine and to maintain an accurate speed reading.