As Pete said turn signal buttons do need to be held in to make it flash on the 87 sportster but does need a full circuit so front signals need to be added there are a few different modules that can be added to the system to make them flash for a certain amount of time after the button press
Personally on the older bikes I prefer to use hand signals but that is just me
Brian
Personally on the older bikes I prefer to use hand signals but that is just me
Brian