Stock motorcycle horns have a single high-pitched tone that is not very loud. Many motorcycle enthusiasts decide to change the horn for either a louder single horn or dual horns with separate tones. A horn relay kit allows indicators to illuminate at the same time as the horn blowing for extra visual location along with the audible sound.
Hold your single horn or dual horns up to the bottom of the swing arm, where it mounts to the motorcycle frame. Mark the areas of the horns on the swing arm with a marking pen. Hold the mounting bracket up to the marks and mark the same spots on the bracket with a mounting pen.
Drill holes in the mounting bracket where marked. Drill holes in the swing arm through the pad and into the hollow tube making sure to only drill through the first side of the tube and not entirely through to the other side.
Place the mounting bracket over the swing arm and line up the holes in each. Attach the horn or horns through the mounting bracket and into the swing arm using an adjustable wrench by tightening the lag bolts with the mounting kit in a clockwise direction until they are tight. Apply silicone sealant around the lag bolts to form a waterproof seal.
Attach the negative and positive horn switch leads into the back of the horn button by inserting each fully into its slot. Negative and positive areas are marked "+" for the positive and "-" for the negative areas.
Connect the horn or dual horn leads to the back of each individual horn by plugging the ends tightly onto each area for positive and negative leads. These areas have negative and positive markings to distinguish them from each other.
Connect the negative and positive battery leads to the battery. The red lead with a fuse in it is the positive side that connects to the positive terminal. The black lead is the negative lead, which connects to the negative terminal. Place the leads over the battery posts and use an adjustable wrench to tighten the battery terminals.
Apply electrical tape at each junction of the horn relay or dual horn relay kit to hold the wiring in place so that vibration from the motorcycle does not pull the connections loose.
Some states do not allow blinking lights on motorcycles. Check your state's regulations at the Department of Motor Vehicles to make certain that this is allowable in your state. You may install a switch in front of the diodes on the signal circuits for the lights so that they will only operate when you turn them on manually.