Adjusting fuel mixture using Gunson Colortune –

Gunson Colortune Single Plug Kit 14mm G4074 Tune up plug

Using a Gunson Colortune to tune a motorcycle carburetor

Gunson's Colortune carburettor tuning kit. (14mm Spark plug) MSA1002

SAMPLEX INTRODUCES COLORTUNE - Motocross Action Magazine

Fuel Mixture Tuning Tools - Pre-XK - Jag-lovers Forums

Gunson Tech Torque Colortune See inside the combustion chamber

GUNSON Ignition plug Colortune 500

Tuning MGB with Gunson colortune from Accuspark

Gunsons Colortune – MGB tips mods and maintenance