WIRING WOES
Ralph Ferrand gets connected.
Almost every classic bike that hops on my ramp has been abused in the electrical department. And in my opinion the greatest contributor to automotive electrical failures is the widespread sale of pre-insulated terminals, which seem to be available everywhere. They’re usually supplied with yellow, red or blue ‘insulators’. They should be called ‘part-insulated’ as the insulation never covers as much of the connector as it needs to for a proper safe job. As soon as I see one on a bike, I know someone who hasn’t a clue has had a go at the wiring. Bike wiring, on the whole, is a collection of very simple circuits. As with plumbing, the secret is to keep the water in the hose. If you think of the insulation as being the hose, you need to strive not to have any holes in the hose for water to escape from. If the integrity of your wiring insulation is breached, sooner or later something will touch something it shouldn’t and expensive misery is the most likely outcome. Insulation is not only there to keep the electricity in, but also to keep corrosive moisture out. For this reason I tend to squirt ACF50 Corrosion Block grease into the female connectors before plugging in the male to protect the joint from any water ingress. When the surface of the metal forming electrical joints becomes corroded, be it the wire or the terminal, it does not conduct power properly and the service will fail to work as designed, if at all, whether it’s a light or the ignition. If poor
insulation causes a short to earth then the conductor will be drawing more current than it was designed to, so it will get hot. The effect of this is to damage the wire insulation making it hard and brittle and therefore prone to cracking and the copper conductor will oxidise on the surface, which will damage the conductivity. The conductor will look dark brown or black if it has overheated and must be replaced. All the above should be unnecessary if the simple rules are followed when working on the wiring, the first of which is NEVER use ‘pre-insulated’ connectors; they are the work of Satan himself!
Ring terminals
Ring terminals vary in size but the most common on bikes are the big ones for battery and earth straps with a 6mm hole
and 10mm² cable and the smaller ones used most commonly for earths to the frame with 6mm bolts and 1mm² wire. Photo 1 shows a few different ring terminals we would use on motorcycles. There are two distinct types that use different crimp tools. The brass ones use the same tool we use on the majority of non-insulated bullets and spade connectors. You can see a ring terminal in the jaws of this tool in photo 2. Working back from the ring itself, the first parts are folded around to grip the conductor itself and the parts behind are formed around to grip the whole wire with the insulator complete. The other terminals are what are known as tube-type non-insulated connectors and use a different crimp tool. This tool is shown in action in Photo 3 crimping a battery lead ring connector with a 6mm hole on a piece of 10mm² multi strand cable. Many people have the idea that soldering is okay for bike cables, but that is definitely not the case. Automotive wiring always uses multi-strand wire, as it needs to be flexible. As a material copper is soft, but it work-hardens. That means that if you keep bending it, the point of the bend will become hard and therefore less flexible and will tend to snap. Single core wire is only used in places where there is no movement and in this instance you can see vibration as being movement. Domestic house wiring uses single conductor wiring, as your house doesn’t vibrate (except when a Harley goes by) so single conductor wire is cheap and suitable. Of course bikes do vibrate, not just from the engines, but also from the undulations of the roads. This is why it is essential to use multi-conductor wire, which is flexible. When you melt solder onto a wire the hot, liquid solder travels up the multi-strand conductors by capillary action and then solidifies, essentially turning the wire into a single core conductor, leaving it vulnerable to work hardening and snapping in the future. Add in that well-known law of physics, Sod’s Law, and you can guarantee that it will fracture when it’s pelting down with rain, in the dark, when it’s cold, miles from home and in an area of depleted mobile telephone reception! So the rule is: don’t use solder in bike wiring, crimp everything.
Splices
If you need to join two or more pieces of wire the best way is using a butt splice. There are various types available but my choice for ease of use is the tube-type. As the name suggests it is pretty much a tin-plated brass or aluminium tube, depending on make. You simply strip back the insulation, push the conductor into the splice and crimp it as shown in photo 4. Sometimes you may wish to join three or more wires and you can feed more than one into each side of a splice. It should be obvious, but you need to ensure that the hole is fairly full of conductor and that goes for most terminals. If, for instance, you have two wires going in one side of a tube-type splice and are only joining one on the other side, you may want to cut back twice the amount of insulation as on the other side and fold over the conductor making it double the thickness thereby filling the terminal hole fully prior to crimping: once crimped the splice should look something like photo 5.
Heat shrink insulation
The easiest way to insulate a splice is with heat shrink. Unless you’re doing a whole heap of wiring I think the little heat
shrink kit from Laser Tools is ideal. The little heat torch is fuelled with fag lighter gas and heats up quicker than I would have expected. I found the secret with using it with heat shrink is to keep the torch moving, as in photo 6. The kit comes with lots of different colours in various sizes and it is perfect for wiring repairs. If you are doing a lot of loom building etc. then a good quality electric heat gun is better, though I have found myself grabbing the ‘demonstration’ torch in preference lately as it is better for getting into tight corners. I can’t see Laser Tools getting that unit back any time soon. Once finished the splice should look like photo 7. In photos 8-10 you can see the various stages of insulating a small ring connector. When any terminal or connector is fitted
properly it should look as though it was fitted by the OEM (Original Equipment Manufacturer) and if it doesn’t, then it’s probably not up to scratch and not safe. Heat shrink is great for keeping a number of wires together. When building a new loom, I tend to wrap the main body of the wiring harness in loom tape, but all the ‘branches’ I cover in heat shrink.
New battery strap
I was doing some electrical work on a 1978 180° Laverda Jota recently, a typical example of heinous Italian wiring at its worst. The battery straps were ‘in need of modernisation’, to say the least. In photo 11 you can see that the original ring terminal was fitted with no form of insulation and the condition of the copper is now looking a bit suspect.
Rather than waiting for it to break off, the customer requested new leads. The original lead with no insulation can be seen in photo 11. In photo 12 you can see the new ring safely crimped onto the cable with no copper showing. In photo 13 you can see the little torch working its magic on the heat shrink tube. Note that it’s nice to use red heat shrink on a positive cable. Photo 14 shows the finished terminal and I hope you’ll agree it looks a nice neat job. If the terminal is in an area where it is likely to get rubbed or scuffed a lot, I often put an extra layer of heat shrink on. cmm