What follows is an attempt to make wiring your chopper understandable, and I'll say from the outset that I am not a motorcycle electrician... and you don't need to be either... just wire up your bike and ask questions as you need to.
These circuits are done in black and white so you can print them off/ photocopy them etc...
This first pic is a basic diagramme for what you will need on your Australian chopper...
1. Power storage... Your battery stores and provides 12-13.5 Volts DC (direct current) to the various systems requiring elecrrical current.
Electrical power for your chopper is a flow of electrons (a bit like water flowing) called current. The electrons (current) will only move if a "tap" (switch) is opened and they can move in a circuit from the battery positive via the item requiring the current (eg tail light) and then back to the battery negative. Wires feed the current to the item. The item is usually "earthed" to the bike's frame which carries the current back the the earthed battery negative terminal.
Broken wires and dirty or corroded connections break this flow or continuity. So... 1. keep connections clean, 2. do not stretch wires, 3. place your electrical components where you cn easily get to their terminals. Many a biker has languished on the side of the road due to a dirty connection or because he has to pull the bike to pieces to get to an offending connection!
Just to confuse you, most Triumphs circuits are the opposite and the battery positive is earthed. But as long as a circuit can be completed, the current flows.
Buy yourself a cheap multimeter for checking voltage and "continuity." A broken wire or dirty connection will not show continuity. You can also check globes. Attaching MM leads to side and pin should show continuity. You can check switch operation too.
2. Charging circuit... Your generator (usually mounted in front of the motor) provides direct current to keep your battery charged. Voltage is regulated by the voltage regulator.
If your chopper has an alternator, it produces alternating current which the rectifier converts to direct current. The rectifier acts as a voltage regulator as well. The alternator (mounted on the end of your crankshaft) produces more electrical current (needed for modern bikes with more powerful lights and extra electrical accessories) than a generator. Alternators can be permanent magnet or electro magnet. Wiring diagram above is for permanent magnet alternator (eg HD). An electro magnet set up (Honda CB's and Yammy XS's) needs an exciter wire. This runs off ignition switch/fuse (when switched on) to the regulater and then to the alternator.
An alternator in good nick will produce 13.5-14.5V. With your bike running at 1500 rpm you can check this with your multimeter across the +ve and -ve terminals.
Blackjacks article (see link on his post) gives a bit more detail about alternators etc...
A bike with a magneto instead of a coil, to provide spark, does not need a battery or generator if it does not run lights...
3. Ignition circuit... Your battery supplies current to your ignition coil. A high voltage (40000+v) surge to the spark plug is induced in the coil when the circuit is broken. This is done at the points. The condenser which attaches anywhere between the coil and points prevents a strong destructive arc at your points.
4. Lighting circuit... Battery supplies power. Ignition switch ususally has a second position for lights... or you can have a separate switch. Current from the light switch goes to the tail light, the globe being earthed to complete the circuit. If the light holder is rubber mounted, you will need an earth wire to the frame or back to the battery earthing point.
Current also travels to the high beam/low beam switch and then to the globe holder in the headlight. Looking at the headlight globe from behind, the low beam is the top blade and the high beam the right. The left blade is the earth. Aftermarket "Bates" headlights have an indicator globe in the headlight shell that connects to the high beam.
5. Brake circuit... Current to the brake light is "made" and "broken" by the brake light switch which is operated either mechanically by the brake lever or if a hydraulic brake is fitted, by a switch in the brake line. ADR's don't require a front brake light until 1995 I think.
6. Horn... In most modern horn circuits, the current runs via the horn button on your handlebars to the horn which is earthed. the horn's sound is produced by a vibrating plate. The sound can be adjusted with a screw and locknut. On jap horns you will need to lever off the cover.
With older horn circuits, the current runs via the horn to the horn button which earths the system when pressed... not aways reliable!
A mate used to have his horn and button hidden, but a bulb horn on display. The coppers would get quite irate and be about to book him when he would then feign sudden understanding and hit the hidden button... told us it used to drive them crazy!
Well that's about it, nice basic wiring system with a minimum of wires... however some fuses are a good idea...
7. Fuses... Preferably, have a fuse on each main circuit after the ignition switch. Reason is that if you have a short you can more quickly find the fault, because only the fuse in the faulty circuit will be blown. 10 amp fuses are fine for all the circuits shown. Electric start circuits need a 15 or 20 amp fuse. On the diagramme above, I've shown a separate fuse for horn and brake light... not necessary... run them off the same (accessories) fuse.
Some extra circuits you may need...
1. Oil pressure switch... current flows through the circuit while oil pressure is low. When oil reaches pressure, pressure switch (sender unit) opens and breaks the current and the lamp goes off.
2. Generator lamp... Like the oil pressure switch, lamp which is supplied with current form the battery is on until generator output reaches a set level...
3. Starter Circuit... If you run an electric leg, you need a much more substantial (and weighty and expensive) battery. The battery suplies current to the starter solenoid and the starter motor via a heavy cable designed to take the high current draw of those two items.
"Switching on" the starter and solenoid is done by current flowing via the starter button to a relay. The Relay also has its own power supply separate to the starter button...
4. Turning indicators... in the seventies the first casualty of chopping. ADR's now require indicators on later bikes (not sure if post 88 or 95) Different states have their own rules on this so check your state authorities it you want to stay legal.
Current runs via flasher unit through indicator switch to left and right flashers...
5. Electronic Ignition... Electronic ignitions vary in their number of wires, but basically the set up is the same as for points. An extra power supply goes fto the electronic module ad an extra wire to the electronic breaker... and no need for a capacitor as there are no points. Module is earthed...
6. Neutral lamp... same basic set up as oil pressure switch except that in this circuit, the newutral switch is in the gearbox and closes the circuit to let current flow, when neutral is selected... a good idea with inexact gear selection...
Drawing up your own wiring diagramme...
The circuits above should cover your wiring needs for most bikes.
On my first projects, I used the wiring diagramme from my manual and deleted every wire I didn't think I needed. Then I drew up my own diagramme keeping wires as direct as possible.
Now, understanding the circuits, I basically draw up a diagramme from scratch, cross checking when there are such luxuries as electronic ignition and starter circuits.
Below is how I started with Michael's 82 Sportster.
(I discovered it was 82 not 83 because the 83 has a vacuum component in its electronic system that the 82 does not, so theres always something to learn!!!)
1. Group as many of your electrical components together to save long wiring runs. In this case, many of the components are close to each other in an electrics compartment. This is indicated on the diagramme below by the vertical group of components from the flasher unit to the ignition module plus the starter relay and fuses...
2. Keep routes as direct as possible. Stock bike wiring looms are designed for efficiency on the assembly line only, hence the headlight full of wires and connectors and 6' lengths of wire that connect components 6" apart etc etc etc ad nauseum!!!!
3. Draw out the components in their approximate places as they are on the bike. Do this diagramme before moulding or painting. This is so you can work out where your bunches of wiring will run. If you need to any holes in the frame to hide it (or preferably mould in some light tubing) you can do it without having to redo anything, and when you come to emplace your wiring those 8 wires running up to the steering head will fit through that hole!!...
Fuses... I prefer blade fuses and make up a fuse holder out of a couple of XE Falcon headlight connectors (see Fits & Bits). I run a wire from the accessories fuse to a joined group of connectors and from which the different accessory ciruits run...
Ignition switch... If the ignition switch is not central, I add a "kill" switch in to the system so I can switch the bike on or off with either hand. Sometimes you will pull up with your hand on the clutch (cos you can't find neutral) sometimes on the front brake (cos the camber is very steep).
More on this over the next week...
