Wiring can be more than frustrating. So we are presenting some "easy
to follow" bike wiring diagrams for Harley-Davidsons®
The first thing to do is to find the best diagram that best suits your bike.
Take a good look because we have included diagrams for most bikes that can use
solid state voltage regulators, making your job of wiring just that much simpler
You are now ready to go to work. Start by disconnecting the battery. Remove the
ground wire; this prevents shorted relays, burned wires and fire hazards. A word
of caution here; do not under any circumstances reconnect the battery until you
have completed the job. Do not connect a battery charger backwards. Do not connect
a battery without a fuse. If you do, you may severely damage your wiring or bike
Before routing your wires, position all components on your bike (such as key
switch, lights, coil, ect.). Keep in mind that all components that generate heat,
like rectifiers and regulators must be mounted in the open where air can flow
freely over them and to properly ground the component.
Now to start the actual wiring. To prevent confusion, work with only one wire
at a time. Connect one end. Route the wire connecting to the other end before
moving on to the next wire. If at any time you do leave a wire unconnected, make
sure you mark the wire showing where it goes.
Use a minimum of 14- gauge stranded
automotive-type wire with at least a 10-gauge wire on the battery and starter
motor. Crimp or solder terminals equally well. Crimp terminals are quicker to
install; just strip a quarter inch of the insulation off the end of the wire
taking care not to cut away any of the strands. Slip the terminal all the way
on the wire so that the plastic part of the terminal completely covers the bare
end of the wire. Line up your crimp pliers over the metal barrel of the terminal
and squeeze it closed without using excessive force. You have a tight, trouble
free joint. Check it by trying to pull the terminal off the end of the wire.
Buy terminals that fit the wire gauge being used and avoid using a spade or open-end
horseshoe-type connectors. Spades have a tendency to spread when and may vibrate
loose at a later date. Find eye terminals that fit screws and studs you’ll
be mounting them also. The eye will tighten soundly.
Don’t hookup any wires without connectors. Avoid splicing wire in the middle
of a circuit when you can run one wire the whole way.
Dangling wires are subject to abrasion damage, engine burns and being cut or
pinched. So use tie raps every
6 inches or so to keep things neat, but don’t
stretch the wire too tight. Be sure to leave some slack in the wire between the
terminal on the end of the wire and the first tie wrap. We recommend you add
a kill button and fuse to your bike. A horn button mounted to the point side
of the coil will do for a kill button.
Finish up by checking all wiring terminals, tie wraps, mounting bolts, ect.,
then connect the battery and test every circuit.
Keep’em on the road.
K. R. Lyon
© 1982 by Jammer Cycle Products
Harley® 74's (1976 and Newer) 12V Using Voltpak Model RAQ
74's and Sportster® with Two-Brush Generator using Voltpak Model VP6 (6V0) or VP12 (12V)
74's with Three-Brush Generator and Voltpak Relay Eliminator
Simplified Wiring Diagram for 74's for 1970 and Later Alternator
74 Alternator System, Kick Start with a Magneto
12 Volt Electric Start System (74 or Sportster®)
Magneto System with Battery, Bosch Regulator and Two-Brush Generator (Sportster® or 74)
6V Two-Brush Generator - Magneto System with no Battery (Sportster® or 74)
Magneto System with a Bosch Regulator and Two-Brush Generator (Sportster® or 74's)
Simplified Wiring Diagram for 74's with Two-Brush Generator
Simplified Wiring Diagram for 74's with Three-Brush Generator
Wiring Diagram for an Electric Start Sportster®