How do you wire a Harley voes switch?

Assuming stock configuration the violet/white wire is hooked to the VOES and the appropriate wire is grounded to the chassis. Ensure you have appropriate VOES for your style bike. A VOES set up for a light bike if installed on a bagger could potentially cause it to run advanced under load, which could cause predetonation (very harmful/destructive to engine). Hope this helps. google Harley VOES and you'll find similar information. FYI the bike will operate in a normally retarded condition without input from the VOES. At high vacuum, such as when in cruising and not under load, the VOES will advance the spark, which will improve gas mileage. Certain aftermarket ignitions dispense with the VOES.