Hi guys, does anybody out there in Guzzi land have photos of the under seat wiring for a T3 that they could post for me to see please? I have bought a wiring loom from Greg in America (which is beautifully made) and I have many more wires on the loom than I have places for them to go on the bike! I realise now that a few items are missing from my bike, the horns and relays are missing, but I have no idea what else I am short of or where they should live. I am having a similar problem with the coils as they are part or a half fitted Sachse system. Any help would be appreciated.
Hello, I have drawn the T3 wiring diagram in colour and can supply you with one see here
I do charge to cover my costs, the cheapest is a pdf copy, but the best for the workshop is a laminated A3 copy. You can download Carl Allison’s wiring diagram for free via thisoldtractor website but beware sometimes the colours are not 100% accurate.
I also have hand drawn each electrical component on my bike (originally a 1974 850T now a cafe racer) showing which colour wire connects to which terminal and where it leads to. This probably won’t help you as I have customised the loom to suit changes I have made, but the ignition, lights and charging system are all similar.
Let me know if you would like any help. Where in the country are you?
Best wishes Chris
Hopefully someone can get you what you need, but there’s virtually no wiring “under the seat” on my own T3 Cali - it’s mostly behind the RH side panel, in my case. Having said that, the chances of a T3 having survived without the owner(s) having relocated a component or two, or replaced/rerouted some wiring are slim indeed.
Greg Bender’s looms are renowned for being “right”, so you might be better off fitting the loom, then seeing where components such as horns can be fitted and connected.
If you aren’t already aware, there are some first-class wiring diagrams available to members of MGCGB, and which you’re going to be grateful that you acquired!
If there are specific components that you would like to see “in situ”, just shout: there’s plenty of owners can show you their variations on a theme, and from which you can choose. Hope this helps.
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I have a spada that has not been messed about with too much and should be fairly similar to a T3, although I think the T3 has the coils under the tank? The loom has never been removed and is mostly standard.
What pictures do you need?
Hi
To confirm what Barry_Conway has said,
there is very little wiring under the Seat. Really, just the Battery to see.
Also, to throw another ‘spanner in the works’ early T3’s have different Electrical component locations to later T3’s, ie, the Coils are under the Tank on early ones and under the L/H side panel for the later ones. The same with several other components.
Maybe you should post pictures of what you have, ie, under the Side Panels and under the Tank, and that will help us help you.
I’ve attached a Sachse wiring diagram. The lower one is the one you need.
Regards, Nik
Thank you very much for the helpful comments. I hope to have another go at it tomorrow. I do have quite a little collection of wires with out an obvious home at the moment, although I am slowly finding places for the extra wires to go,
I still don’t know what I am missing because it has never been there since I got the bike.
Ok, so the first thing that jumps out is the Reg/Rect location. It should ideally be mounted under the Headstock, as in my picture The aluminium box with fins act as a heat sink so really needs to be in good air flow. Also, i suspect that is the wrong one assuming you have the original Bosch Alternator. Ive uploaded a wiring diagram for the Electrexworld RR45. Recommended you use an RR45. You need to double check what you have!
For a Sache Ignition system, you should really be using the green coils but as you already have grey and they aren’t cheap, stick with them.
So, really i think your main problem is that most of your electrical components are non std, but thats not a bad thing just makes wiring it all up more confusing as i’m sure you’ve realised. If it was me i would remove the loom, work out where all the compnents go and then start at one end.
So, relocate the Reg/Rect to under the Headstock. Coils are good. Starter Relay under L/H side Panel. Flasher Relay under R/H side Panel next to the Fuse Box. I think that will get you started.
Regards, Nik
Hats off to Temp6456G for building his bike in what looks like the dining room! 
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The coils are Dyna coils like mine and I see that the heads have been converted to twin plug, also like my heads. This is a great conversion it gives more power and the engine is smoother, as the flame front no longer spreads from one side of the cylinder but is more even causing less of a rocking force on the small end of the con rods.
I found it made fuel consumption better too as there was less unburnt fuel exiting the cylinders through the exhaust.
I also rebuilt my bike originally in the house, but now I am happily married again 
I am forced to keep my bikes in the garage!
Enjoy!
On closer inspection that might be the cutout for the inner cylinder head bolt…I’ll get my coat!
Thank you very much Chris, Nik, Barry and Don. I have made some good headway today, with your help, in the lounge with my wife, doing her hobby at the same time. It is an experiment!
Chris you were correct it does have twin plugs heads and although the coils look grey they are a dull green and have twin lead outputs. I bought the bike as a stripped back Afrika Corp desert replica, (in pink camouflage) with most of the wiring removed. It’s my first Guzzi. Not the last! I now have a long abandoned Cali too,but the wiring is quite crispy and seems different in many ways with plenty of mods, it has a strada engine fitted.
The Sachse ignition system was in a box but without some of the instructions. The voltage regulator is an Electrex world RR500. Does anyone have experience of these? It has a Brown and a white wire that I don’t know the purpose of. I have also bought Greg’s relay kit as an added complication. I am moving the regulator to the front of the bike as suggested by Nik, thank you.
I am very much looking forward to riding it after what Chris said it should go like.
Thanks very much to you all, it’s very kind of you take the time to post stuff to help me.
I am near Chippenham in Wiltshire.
All the best, Jim
With regards the Rectifier / regulator, I have a RR451 on my California 3 and asked Electrex about an odd wire. There reply was as follows…
2 x yellow - Alternator
1 x red - Battery +ve.
1 x brown - RR451 has a voltage sense wire which is the brown one. This is connected to a switch live so that when you turn the ignition on the brown wire has 12volts to the regulator/rectifier. If you have no voltage due to bad connection in the switch or connectors, the unit will overcharge. (This senses the voltage in the system to see if the battery needs charge. I have connected this direct to the battery, it doesn’t need to be switched)
*1 x black Battery -ve.
1 x white - Charging light. (Mine is disconnected as it doesn’t go out till about 2K revs)
Looking through their website, I don’t see a RR500 listed. They are very good at responding to email queies about their equipment
info@electrexworld.co.uk
Edit, Just another thought, do you know what alternator you will be using as the standard Bosch system requires a voltage to be applied to the rotor to create the magnetism and that is usually fed from the standard Bosch Rectifier charging light circuit.
Thanks Don I have had a look at the alternator, it’s an Electrex ADP921-01. It seems to have just 2 yellow wires coming out of it. The bike has not been run for around 12 years so I don’t know whether it ever ran in this configuration.
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High output alternator 