MKIII (Lord Enki) Re-Wiring

Okay, so far I have diagramed out the Battery, 2 grounds, 1 30 Amp inline fuse, 1 8 fuse Panel (6 Switched and 2 Un-Switched. I have it set up with in un-switched fuse going to a relay to switch on the buss for the 6 switched fuses and 1 un-switched line going to an external power jack.

I would like comments, am I on the right track. I may have too many fuses, but that ok just as long as every thing I hook up is done correctly.

Shoot at it hobot!

Nothing wrong with an 8-gang fuse block. The idea is to isolate the ignition circuit from failures in all other circuits. You want a failure in, say, your headlight wiring to open the lighting circuit fuse, leaving the ignition intact and operating; as uncomfortable as it is to be riding at night without lights, at least you can get home. Your relay scheme is a bit confusing, however. The point of adding relays is to be able to directly supply current to power-hungry circuits (think lights and horn) without having to run the current through the handlebar switches or ignition switch. This requires at least 3 relays, one each dedicated to the horn, low-beam, and high-beam circuits, respectively. Only the relay exiter currents pass through the switches. IMHO, putting a relay in the ignition circuit is a bad idea.

Saber13 said:

1 30 Amp inline fuse,

Click to expand...

20A should be more than adequate (as the original "book" rating of "35A" refers to blow rating, so is 17A continuous).

rick in seattle said:

Nothing wrong with an 8-gang fuse block. The idea is to isolate the ignition circuit from failures in all other circuits. You want a failure in, say, your headlight wiring to open the lighting circuit fuse, leaving the ignition intact and operating; as uncomfortable as it is to be riding at night without lights, at least you can get home. Your relay scheme is a bit confusing, however. The point of adding relays is to be able to directly supply current to power-hungry circuits (think lights and horn) without having to run the current through the handlebar switches or ignition switch. This requires at least 3 relays, one each dedicated to the horn, low-beam, and high-beam circuits, respectively. Only the relay exiter currents pass through the switches. IMHO, putting a relay in the ignition circuit is a bad idea.

Click to expand...

+1 to all that

On my mk1, I didn't even bother with the relay for the horn, (it's got a Fiamm fitted), but a horn relay is a worthwhile upgrade to help out the ageing handlebar switches. I also made do with just two fuses, the main battery one, and the supply to the headlamp relays.

Be interested to see your final design, and the installed wiring, as I had planned a bespoke fuse/relay array in the battery box, but had to accept I had other things to fix.

I like the relay for ignition, not so much for current, but voltage drop through ign switch and kill switch. I even have my old harley wired so the relay gives a full 12-volts while the starter is operated. Seems to work, she starts easy as!
Cheers Richard

Thanks all for the input. I will change the inline Fuse to 20 Amp. The next step will be to add one subsystem circuit at a time and throw it up for review by those that have been down this road and have more experience in the electrical arena than myself.
I have pictures of the removal of all the old wiring and prepping for the new, I will start posting those this weekend. I was going to build a frame mock-up out of PVC, but do to a time crunch, I will just run the wire on a board. A board seemed to work for the little old ladies in tennis shoes that made all the harnesses for the Apache I flew.

As for relays, other than the one powering up the 6 switched circuits, I am looking at using one for the horn. I am using the original horn because, 1 I can't get it out and 2 I like to keep as much as stock as I can and not compromise reliability. I will us 2 relays for the head lights, open to suggestions.

Again, thanks for the advise.

Chuck

Chuck,

While a bed-of-nails works well for building several limited-production harnesses, your project is a one-off, and you'll find it easier to simply build the loom on the bike, running the wires point-to-point. Feel free to divide the backbone runs into two smaller bundles, one on either side of the backbone. Leave the carburetors and filter box in place while wiring to preserve access; that area is a busy one for wires.

Now is the time to convert to negative ground, and code all ground wires black. While the "hot" wire convention of blue-brown really poses no problem (you'll simply have both red and blue-brown "hot" wires), using the original red ground convention creates a real mess if you ever make this conversion in the future.

Document your work with a harness diagram as you wire.