Re-wiring, Part 5 (The main loom finished) – 13 Dec 2015.

At the end of my last post I had fitted the partially built main loom to the bike to get all the cable lengths right. I had to shorten a few and thankfully none were too short. The loom then went back on the bench ready to fit the rest of the terminals.

Before I did so, I mounted the headlamp relays on the inner mudguard. I’m not too worried about drilling extra holes as I have a brand new spare hidden away.


When wiring the connector blocks for the relays I noticed that I have two different contact pin arrangements. Both sorts of relay have normally open contacts and the same physical pin layout but internally they are wired differently. I have come across this before. I have called them Type A and B. Contacts “30” and “86” are reversed.

Relay pin layouts

The two headlamp relays are the first “normal” type and the starter relay is the “alternative” type.

I also had a second thought about the bulb holders in the speedometer and rev-counter. I realised that, rather than use earth tags on the back of the instruments I could get push-in bulb holders with two tags. I’ll be using these instead.


I went ahead and fitted all the terminals. Here is the final main loom. At this point the relay connector blocks aren’t fitted although their latching terminals are.


The warning light and instrument end.


Here are the terminals for the connector block under the tank, the two original bullet connectors to the switch loom and the four additional bullet connectors for the new headlamp circuits. The red wire is the charge warning light connector on the rectifier and hidden behind it is an earth terminal. Lastly, there are connections for the extension to the front brake light switch.


Here the large and small terminal are the +ve connections on the rectifier. The blue is power to ignition the coils. The two wires (black and black/white) are for the electrically operated fuel tap. The last bunch are three wires to the starter relay (more about this later) with the green one to the neutral switch on the gearbox.


This lot end up under the seat. Besides the wires to the fuse box there are the load and switching wires for the headlamp relays, connections for extensions to the rear brake switch and the tail/brake light. There are also three earth cables connected to one ring terminal.


I know I’ve gone on about all this at length but I have good reason. This is also my record of what I’ve done and I might need to refer back at some point!

Earth return circuit.

I’ve said previously that I was going to include a separate earth return circuit in my rewire. This is to avoid using any part of the frame as part of the earth circuit and to ensure that continuity is good. It’s not difficult and just entails joining the various earth points together and to the main battery earth.


These are the front two connections. One is on the earth side of the rectifier board and the other to a bolt on the engine timing cover.


Next the wire goes down to where the battery earth cable will be then back up again


to a connection point on the mudguard under the seat.


This is just a convenient place to run the various earth cables to under the seat. I think it’s where the indicator flasher relay goes if you have one.

3 o’clock in the morning.

I couldn’t sleep and took to thinking. I was a little concerned that my planned layout would mean three connections to one terminal on the fuse box. I don’t mind using one piggy-back connector but two is a bit much. I had to get up and write myself a note. “The start relay can take its power supply from the bottom end of the heavy cable from the battery to the starter. It doesn’t need to come from the un-fused supply side of the fuse box”. This means there will only be two cables at that point – the main supply from the battery and a cable to my headlamp relays.

The following morning the alteration was made. The old red cable was cut and pulled from the loom and a short length with a ring connector made up. Here you can see the relay connector block fitted. The red cable with sleeving and ring connector supplies current from the main battery terminal on the starter to the load side of the relay. The other red cable is the switched load out to the solenoid on top of the starter. The brown wire is the trigger cable from the start button and ignition switch. The black is its earth return. The green is for the neutral switch.


I’ve done a lot more but this post is long enough already and it’s late.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s