There is still plenty of shit to do before I break it down for paint. I’ll try to wrap all that up in the article after this one. Today we are going to deal with the electronics. Since all this still has to be removed for paint nothing will be fully installed. What I’m going to do is get all the prep work done including buying everything and putting some holes in my new frame.

First thing you need to do is have a plan. What are you going to use in your bikes electrical system? Are you building something with points? Or are you going with all the latest gadgets? How complicated the wiring becomes, if you build it from scratch depends on what’s included.

Like many of you out there I don’t like to use things that are not NEEDED. We posted a sample wiring diagram in an earlier section. I’ll be using it pretty much exactly as is. After all it was drafted for this bike.

You’re going to want to pull the tank and seat off to get them out of the way. Now start laying the wires out right on the frame. Make sure that you over estimate the lengths. Leave yourself about a foot on each end right now. All we are doing here is making sure we have everything and getting an idea where the wires need to go. I won’t actually be cutting anything until the final build.

Believe it or not, this is just about all the electronics for this bike. All the wires, and all but the fuses and blinker module. Looks simple doesn’t it?

I’ll be drilling a hole in the backbone near the neck and one at the rear under the seat to run the wires. I’ll also be drilling one hidden inside the top motor mount point for the ignition and headlight wires. Since I don’t have a right angle drill motor I’ll have to wait until I pull the motor for that one.

When you drill holes like this for wires to go through you have to protect the wires. The last thing you want is a designed in short circuit. So deburr the holes inside and out and use grommets wherever you can. My wiring hole up front by the neck can’t use a grommet. It is drilled at an angle and fished out a little for style. Here I just have to be extra careful to make is smooth. The wires do have multiple jackets since I bought cables for the various circuits. All surplus NOS. You can find just about anything you need and it keeps the wire bundles tight and small. But remember, I’m using an electronic module for my blinkers that has low current inputs. That’s how I can use the small 22AWG wires in my cables. The wires coming from this to the actual blinkers are the same size. My blinkers (covered next section) will be all LED. That means virtually no current.

If you use regular bulbs you will need much larger wire. Stock units draw around 2Amps each. For that you better plan on 18AWG wires. For my bike’s handlebar switches I’m using a four conductor jacketed cable with 22AWG conductors. If I could have found a three-conductor cable I’d have used it since this is just 12VDC and the two wires to the blinker module. The whole cable is about 1/8in. Nice and tight. A two-conductor cable about the same diameter will feed the headlight with 18AWG conductors. That will be plenty to handle the current of the headlight. The headlight’s return is internal. I just need to add a jumper wire from the front end to the frame. Stock HD’s do the same thing. I’ll use more of the four-conductor cable for both the front and rear blinkers. Which reminds me I better get the damn CAD drawings done or I won’t have any.

The ignition and headlight switch will go in a custom plate on the top motor mount. With my minimalist wiring system the only other thing to mount besides the lights is the blinker module and three fuses. It’s such a small little box and is already water proof I’m just going to drill a hole in the bottom of the battery box and hang it there. I’ll put the fuses right next to it. That makes all the wires perfectly placed to either go to the rear lights or meet up with the ones coming out of the frame backbone.

Seems a bit simple doesn’t it? In the stock setup there would be some relays to add confusion. I’m using a car style ignition switch that has the START position built in. Look around and find one with the ability to handle 15Amps of current. I’m not completely sure about a HD but a car solenoid typically draws 8 to 10Amps. I bought one made by Evinrude, ya the boat people. It’s waterproof.

That brings up a point some people don’t realize. The circuit breakers and fuses that are used in electrical wiring are not there to protect the “items” you are providing power to. They are there for safety. Fire safety!

When you run current through a wire it gets hotter. Hopefully not much, but all wire has some resistance in it. When you run current through resistance you get heat. The resistance resists the flow of current and since we never get anything for nothing, that has to consume some of the power. Don’t get all caught up in the various terms just remember if you try to run too much current through a wire it will get hot. If it gets hot enough the insulation will melt or worse burn. Plastics like PVC burn really well, and they like to drip burning shit on whatever is under them.

Most PVC insulation is what we call 90C wire. What that means is you can run enough current through it to get the wire up to 90 degrees Celsius. That is hot but it’s within the rated temperature of the insulation. It’s the absolute max though. ALWAYS try to run them cooler. Remember engine heat? The engine heat makes it hotter so you have to “derate” the wire. This means that if you should be able to run 15Amps in a specific wire size you won’t be able to under the elevated temperature. I like to use 80% as a good rule of thumb. You can argue that the wind traveling over the wires, where they are exposed reduces the temperature. That would be true but what about the parts that are enclosed? Don’t push it with the wires or you may get to push it with the bike.

Wire Capacity - Data Compliments of Alpha Wire Company:

22awg => 8A
20awg => 10A
18awg => 15A
16awg => 19A
14awg => 25A

The actual blinkers and taillight are still a bit vague to me. I’m planning on using a set of the new stock HD blinker bodies and making new inserts to fit my LED setup. Take a look at the end of a wheel gun and that’s the pattern I’ll be using. A circle of six and one in the middle. I’m going to talk my friend Joel at J and T CNC into doing them for me. The stock reflector section and bulb sockets are held in with a rubber grommet. If I pop that out and install a new one with seven small reflectors machined into it I’ll be set. These will be brighter and draw about a hundredth the current. Heavy electrical loads mean more draw from the charging system. That means more rotating resistance for the motor and less power for you. Why? LED’s are not subject to vibration failures and don’t burn out in a year. The only reason I wouldn’t recommend everyone go right out and change, is because the prices are ridiculous!

On to The Next Installment...

Back to The First Page Of The Previous Installment...