Sergeantwoodie

Hi everybody my first visit to this site . I am a dinosaur rider having been an Army Dispatch rider on BSA machines I then used all Yamaha CC step thrues inc Townmate Yamahas . in The last 10 years I own 4 BSA machines I am now selling my A10 Gold Flash through health reasons , I have purchased to continue riding a Yamaha RXS ;1500 miles on clock . How do I get at the bulb in the Rev counter I have no Manual only owners the subject is not mentioned Help please