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The Latest, Greatest Triumph Rewire

- By Pete Snidal, (C)2003
I've just finished writing a service manual for the Royal Enfield Bullet, and in the course of correspondence with various buyers of this book, have ended up in the process of writing a second smaller one strictly on puzzling out wiring modifications for the many models of these fine machines. This got me to thinking about my old "22-wire Triumph Scheme," and thus this little article. As it happens, I just wired one of my T100 projects last Saturday, and I can share the thinking there very easily.

It will also work fine for an Enfield, the only difference being they are (-) ground, so it will require careful reading.

This plan will leave you with a single switch, with three positions. Center-Off, to one side will give you ignition, and a front running light if you want one, and to the other side will give you ignition and full lights.

The Main Switch

This is a "switch-centered" wiring plan - pretty well all connections are through the main switch's 6 terminals.

You can use an ignition switch or not. Since anyone with a half a brain can figure out how to hot-wire a Triumph in about 10 seconds, anyway, I seldom bother with them anymore. - The only theft protection starts at the fork lock, proceeding through chain to telephone pole, sonic alarm, silent alarm, lock in garage, etc. Leaving an unlocked Triumph lying around waiting for someone to hotwire it is ridiculous - you may as well leave the key in it. Besides, the key ring will just p*ss you off by scratching your paint when you're running, so I just forgot about the ignition switch altogether.

If you choose to be anal about it, you can leave your ignition switch in place, and hook it up or not - who's to know? If you want it functional, just wire it between the ammeter and the 3-4 jumped terminals in the plan below.

A Note on the Stock Switch

The stock switch is a bit overcomplicated, with its 8 - count 'em - 8 terminals and all. This was necessary to make it possible to leave the park lights on with ignition off - a requirement in parts of Britain but nowhere else, certainly not here, So I put mine aside carefully in case I ever need it for a total restoration project, and went with a brand-new ten-amp (minimum) DPDT (Double-Pole Double-Throw) center-off. This is an especially important choice if your stock switch is defective or gone.

The Main Switch

For the main (and only) switch, I chose an Electronics component DPDT center-off 10 Amp switch - mounted in the headlight where the stock one fits. This switch controls ignition/running light (on with ignition) and head/tail/ instrument lights. Let me start with a little table describing the 6 connections to and from this switch - it pretty well describes the entire wiring scheme. You may want to scribble down a schematic as you read this article. In this terminal description, I'm calling the two in the center 3 and 4, and the ones at the ends 1 and 2, or 5 and 6. Here's The Connection Chart:

Jumped to 5, Both to Ignition Coils
Power to Ignition Coils, Horn
12 in.
Running Light
Power to Running Light in Pos A
8 in.
Jumped to 4, Both to Ammeter
Power In
5 in.
Jumped to 3, Both to Ammeter
Power In
3/4 in.
Jumped to 1, Both to Ignition Coils
Power to Ignition Coils, Horn
1 in.
Dip Switch Common, Instrument Lights, Tail Light
Power to Lights in Position C
40 in.

That's about all you need to know. Connect the taillight, instrument lights, and Dip Switch common to terminal 6, and connect all the other terminals as shown in the chart.

Choosing a Rectifier

If you still have your stock Lucas Rectifier and Zener, you may want to consider that the Lucas Selenium Rectifier - the finny thing under the seat - is likely dried up and no longer very efficient. You can replace it with a very inexpensive 10 or 20Amp Silicon Bridge Rectifier from Radio Shack, and continue to use your Zener Voltage Regulator - the finny thing under the headlight - if it still functions properly. If you do, connect the stock Zener to the Yellow wire on the Ammeter as well.

Or you may want to go whole hog and replace with a unified R/VR, such as a Tympanium. Or Boyer Powerbox, or Positronics - all are proprietary Bridge Rectifiers with built-in Zener control circuitry.

The Rectifier Connections

If you stick with the Lucas, your (+) ground will already be taken care of - the mounting stud is also the (+) output. In the case of the others, there are separate DC outputs. The rectifier has four connections. Two AC, from the alternator, and Two DC, a Black (-) and a Red (+). It doesn't care if your system is Positive or Negative Ground; you just ground the (-) or (+) according to taste - it's best to stick with the stock arrangement, whichever one it is, to avoid being hunted down like a dog and gutted like a fish by some subsequent wiring-challenged later owner or mechanic.

I use black siamesed lamp cord - #14 or #16 gauge - in a number of places in this setup. It's neat and black - the most unobtrusive possible alternative for Alternator output, Stoplight and Taillight connections. So I solder the siamesed cord first to the alternator output lines, as close to the chaincase as possible, staggering the cuts to protect against shorts, using shrink tube and resin-core solder. Next, I route this wire as neatly as possible to the Tympanium, and make the same connections to its AC outputs (the two of the same colour) at that end.

I then ground the appropriate colour DC output line - Red for (-) ground, Black for (-) ground, to a clean chassis connection near the battery. I also connect this chassis ground to a fresh fuseholder, the other side of which is crimped to a ring connector for the battery ground terminal. [(+) in Brits, (-) in most others.] I leave the chassis bolt loose for the time being, because I'm going to finish the wire stringing with a Ground Bonding Wire to all the ground points later.

The remaining DC output wire - the Black one in the Triumph scenario - I connect to a second fuse holder line. The other end of this fuse holder gets soldered to both one of the conductors going down to the stoplight switch (the feed line) and also to a yellow line going forward to the ammeter (+) connection.

The system is now protected from short circuits powered by either the battery or the the charging system, and the charging system will soon be connected to the rest of it through the ammeter.

The Ammeter connections

The Ammeter is fed by a Black (-) wire from the battery, and feeds the two center terminals on the switch - 4 and 5 - by means of a yellow wire connected to its (+) terminal. The (+) terminal also connects to the yellow wire from the Rectifier fuse.

Connects to
Battery (-)
Power to and From Battery
Yellow to Switch
Rectifier Output Fuse, Master Switch Input - 3 and 4 jumped
Power to and from Battery

No Ammeter?

The minimalists among you may elect to eschew the ammeter - relax; that means do without it, nothing to do with eating it! If this is your choice, then only one wire from the battery to the switches and zener will be required. Just go straight from the Rectifier output to the switch input terminals, and to the Zener as well, if you're using one. Twist the wire ends at the rectifier, but don't solder yet- there's another one to connect first.

Now for another piece of siamesed black lamp cord - this time up from the rear brake light switch to the taillight. Strip and connect the pair at one end to the stop light switch, and route the line up past the rectifier to the taillight. Cut one of the conductors as it goes past the Tympanium unit, mounted on the rear of the battery box. The lower leg of this conductor will be the stoplight feed, and the upper, taillight end will be spliced to the blue wire from the main switch to feed the taillight.

Now, using resin-core solder and shrink tubing, "tee" the stoplight end of this into the Yellow Tympanium output wire from the Rectifier fuse to the ammeter, (or switch) for stoplight switch feed, and then splice the taillight end to the blue line coming back from the Main Switch. Presto! - nice, neat, black twin line between taillight and stoplight switch, stoplight switch fed by rectifier output line, and feeding stoplight, taillight fed by blue wire from Main switch.

The Horn

The Horn is connected to one of the coil (-) inputs, with its ground connection being done through the horn switch. The horn power wire is about 6 inches long, the wire to the horn switch connection inside the headlight is about 12 in. long.

The Coil (+) lines are teed to their respective lines to the points and also to their respective caps in the condenser pack. I also use black siamesed lamp cord for a neat connection down from the coils to the points - I used the kind that has one conductor marked with a grey stripe, so's I don't get screwed up with Left and Right point connections.

A Capacitor

A Charging system capacitor will allow your motorcycle to start with a dead battery. It smooths out the pulses from the rectifier/alternator. You want one. A 4000 uFd 40 VDC Capacitor, also from the electronics shop, is connected between the Yellow line from the Tympanium to the Ammeter, and the chassis ground. (+) terminal to ground with a red wire, and (-) to the yellow line with a Black wire. (Reverse these colours if you have a (-) ground system.) You can use any point on the Yellow feed wire you wish, from Rectifier to Main Switch.

Chassis Grounds

Best way to ground things is with a ground wire, connected to the chassis in as many places as you like. A piece of #14 wire, starting at the Zener (if still used), and connecting to the headlight ground, the headlamp body itself, a coil mounting bolt, the Battery Fuse (side other than battery!), the Rectifier ground and a mounting bolt, and the taillight body should suffice. Just peel some insulation off at each point and wrap the wire around the mounting bolt in question under a washer, or solder the wire in question in place. You should also connect the ground to a motor mount - one of the torque stays at the top of the head for instance. Now, you're Grounded!

Now we have Ignition, Horn, Running Light, Head/Tail/Instrument Lights, and a Stop Light. We also have charging system feed to the "hot" battery (-). The ammeter is connected in such a way that it shows NET battery charge or discharge - it the system is "holding its own," there will be a null reading on the meter. Ifthe system is drawing "help" from the battery, it will show a discharge, and if the battery is being charged by the system, it will show a charge. (Nb: once the battery has attained a full charge, there will be no charge shown, since it will have the same voltage as the regulator output. No worries.)

The overly restless may point out that the Tympanium is always connected to the battery with this system. That's true, but draw should be minimal to non-existent, and in any event, for long-term storage (more than a week or two), you should take out my battery fuse anyway.

Once you get the wires all routed neatly and connected, tape them into a nice neat loom and fix it to the frame with a few black snap ties.

Now you have a minimum of wires and connections to go bad, hopefully a nice schematic that you built as you went through this article, and a lot less trouble with your wiring system - one that by now you understand. That's how hippies wire Triumphs! You're welcome!

-Pete Snidal