Wire harness repair/restoration

All to do with wiring, charging or just trying to figure out whats gone wrong.

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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Good for you Neil, and if you have any questions about restoring any parts don't hesitate to ask, as we are all here to help fellow members.
I've got to get the last rear harness set up to this stage of being sectionally taped so it may be done in the next few days.
Its time consuming stripping any harness all down to its individual wires and cleaning the casings terminals and sockets, and besides I don't sit and fiddle with it nonstop, I prefer to do some then come back and do some more in stages until its done.
At least its good to know the wiring will be up to scratch and functioning properly once its done for the bikes using these updated harnesses.
Two strokes, its just that simple.

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MikeH1A
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Re: Wire harness repair/restoration

Post by MikeH1A »

Allan, you never cease to amaze me with the level of knowledge and breadth of skills that you have ... not to mention the patience for such tasks :up: Another great job Sir!

I'm thinking it may be easier to just lay all the bits of my Buffalo out on the garage floor and wait till you come to this neck of the woods on vacation and then get you to sort her out LOL.

Mike
Burt Munro + John Britten + Kim Newcombe + Ivan Mauger = Kiwi Street Cred

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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Thanks for your kind comments Mike, I'm hoping others seeing these electrical wiring posts might decide to take up the reins and give them a try.
The third rear harness I mentioned did not get done yet as I got another harness to do just today which will make four in total so I need to get cracking at it.
I stopped because some other work got in the way, mainly regular things, and some gauge restoration which is good as that helps fund the ebay buying.

I also recently bought some waterproof cylindrical high end car audio fuse cases so I can use the traditional glass fuses, these ones have gold plated contacts in the case and on the fuses as well, for proper conductivity.
I also bought some single flat pin connector sets to replace the bullet type for the actual fuse case pigtails I plan to make up for this section of the harness updates.
Once I get around to making up the fuse case with the wire pigtails and connector sets I'll post those photos.

You just gave me an idea about laying a buffalo out on the floor and then taking a photo of the sum of its parts. :up:
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
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76 Suz TS400
76 Suz GT750
81 Suz GSX1100
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

I had some other harnesses out for inspection recently and so I set about fixing these as they are simple and quick to do.
After stripping these temp gauge harnesses down completely and cleaning the brass connections, eyelets and socket, then on went some new 7mm black sheathing which gives these results. The old sheathing is a bit short so I extended the new ones to 11 1/2 inches.

Image
Three in a row.

Image
Bagged until ready for use.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Taking a look at the gear indicator harness for restoration, you first need to test it if its a used one you obtained.
If you know its working then you can skip the test portion and go right on to the restoration.
For testing the display you will need a 12 volt supply, or a simple 9 volt battery can work to make things easy on the bench.

Touch the orange wire to the positive terminal of the 9 volt battery or DC 12 volt power source and the other wires in this order to the negative terminal, once you have removed them from the socket and marked their locations.

Orange and white/yellow # 1st gear
Orange and red/brown # 2nd gear
Orange and green/Blue # 3rd gear
Orange and yellow/ blue # 4th gear
Orange and brown/red # 5th gear

To remove the terminals you need to press down on the little tang on each terminal and push the pins out of the white connector towards the wire side.
Usually the sheathing is hard and broken so you will need to replace it, but remember to add about an inch more as it shrinks when it hardens.
Clean the wires, socket and unit of old dirt with a product such as Simple Green and blow it off with compressed air. Don't worry about wetting it, the units have all the connections sealed in the display so you wont destroy it.
You will also need to dip the terminals in vinegar and scrub the ends with a soft brass brush to clean them up.
Make sure to bend the tangs back up by sliding an exacto blade under them.
Once its all finished your unit should look like these ones shown here which are for the 75-76 models. The 74-75 had a slightly different style of display unit as did the 77 model.

Image
Three 75-76 gear indicator displays now tested, cleaned and ready for use.

Image
Three types of unrestored gear display units shown here, from left to right: the 74 to early 75, the late 75 to mid 76 and the very late 76 to 77
Surprisingly the middle unit seems to be the most durable, both the 74 and 77 types have a high failure rate on the segments of the '8'.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
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jackyman
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Re: Wire harness repair/restoration

Post by jackyman »

Great informative thread, just about to embark on giving my harnes some TLC so its certainly looking to make the work a lot easier. Just one point Id like some help on, what do you use to shift them pins from the sockets? I know there are specialist tools for removing them, but what do you use? Any tips/techniques that could prevent us from going grey or insane would be a great help.
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

To shift the pins from the sockets simply grind the end on a paperclip into a flat tip, its simple and effective. Push it into the slot and press down to flatten the locking tab to remove the terminal. Use an exacto blade to raise it back up when putting them back in.
Rick the terminals were quite easy to make and work perfectly, thanks for your kind comments.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
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Re: Wire harness restoration

Post by Cliff »

Suzsmokeyallan wrote:Heres the gear indicator units restoration in progress:

Image
As usual, a scrapyard fresh item, its scruffy looking appearance with the usual grime and age related issues are as seen here in the photo.


Image
Here you see the sheathing has been removed and the terminals and wires are now clean, along with this the terminal face has been lightly sanded with #400 paper to dress the surface level for the wire contacts.
The outer metal body and centre barrel has been cleaned up as well as the harness clamp and the connector block.
I've got to fit on some new sheathing and get a new sealing o-ring, once thats done the connector will be refitted and this part will be back in service.
I just changed my unit today (I have spares!!) because it was leaking oil at the connector! Now I see that there is an o ring under the connector! Thanks for the picture!!
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Cliff that o ring is a difficult size to locate, and Suzuki dont offer it, but I did manage to find some after doing some searching. If you need one let me know.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Onto the front harness for a Buffalo and here's whats going on with this one. To simplify the restoration and updates I plan to make to match the rear ones I updated, I stripped it bare to individual wires and began the cleaning process of all the terminals.
The splice joints will be re-taped next and then the sockets cleaned up to begin reassembly.
Some wires will be upgraded for gauge size and some like the orange feeder with its branch circuits will be completely replaced with a different layout.
The photo shows the sum of the wires, minus a few, the main red battery wire, the orange wire with its plethora of branched circuits and the orange/white wire, all of which will be replaced.

Image
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Since I'm doing some work on other GT750 main harnesses I thought I'd show this.
Looking at the rear harness for the GT750 heres an issue that defies logic. The first photo is of two orange wires shown against each other for a gauge comparison, these are the main switched power outputs to the rear section of the harness.
The upper wire shown with a bigger gauge sends power to the rear brake lamp switch, indicator relay and fan relay if fitted, while the smaller gauge one shown below it, sends power to the three ignition coils as well as the voltage regulator.
You would think they would have used the larger gauge wire for the more important ignition coils/regulator circuit, but nope thats too easy; and this is a common design issue.

Considering the importance of the ignition coils and regulator circuit, a micro connector is not the best size to use in this situation either.
As for the later main under tank three pin connector block, changing it from the original separate bullet connectors to the small zinc plated pins of later bikes was,,, well if you've been around enough GT750s you've seen plenty of them burnt out or melted.

Image
Wire gauge dilemma, what were they thinking.

Image
After stripping the rear harness for the restoration/upgrades, the wiring shown in the left bag is to be replaced/updated. The wiring shown in the right bag will be retained and is shown already cleaned.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Watch out for things such as this when checking over your wiring. This is a right side switch I bought off of Ebay for restoration, and upon opening this was noticed.
Look at how close the orange ignition wire strands by the solder joint are to the body housing on its right side, its less than a millimeter away from the metal housing.
You can also see some green corrosion on the same side of the solder joint which means its possible this would be arcing to the ground when water was in the switch.

Image
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
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tz375
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Re: Wire harness repair/restoration

Post by tz375 »

Nice work Allan. I went through 3 or 4 right switches recently and that confirmed for me that the ignition circuit needs a relay. Now my right side switch carries very little current and the ignition has its own fuse and relay. IIRC I don't think I routed any of the ignition electrons through the main switch either. That just carries the relay latching power and the other circuits are fed directly from a fuse panel carrying 12v straight for the battery, but my system isn't stock looking and that could be an issue for some restorers.
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Richard the virtues of using relays are excellent and I applaud you for doing so. In the case of these simple schematics on the bikes moving up in gauge size to the next one for these undersized wires is so simple it defies logic not to do it.
I want the harness to look simple and stock in its appearance yet be an improvement for power distribution. Most people wont even strip a harness and rebuild it, far less add some switched relays and the circuits they power.

As you know, with a relay you still have to switch the load onto bigger gauge wires to the location you are powering, so in the case of the ignition, the wires from the relay to the coils for example have to be increased. If you're doing that section of harness upsizing why not simply upsize the remaining wires in that harness circuit for simplicity and forget the relay.

Suzuki did not learn anything obviously in 40 years and still build harnesses to a price point, lets take a look at the Bandit kill switch. The wires from the connector to the switch are even longer than the GT as it connects at the front of the fairing. The kill switch wires are even smaller than those on the GT.
So would it not be easier to simply upsize them as a retrofit like I'm doing on the GT kill switches and solve the issue quite easily.
All it takes is two lengths of orange wire at 14 gauge over the two stock ones at 18 gauge.
I have some of those Bandit kill switch harnesses to do so I'll post up a photo to show what they did at the factory and how the retro fit I did turned out in comparison.
Good musings on the topic though, to relay or not, it all comes down to a personal preference.
Two strokes, its just that simple.

69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
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tz375
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Re: Wire harness repair/restoration

Post by tz375 »

I didn't keep the calculations but last time I did it the wires from switch or relay to the coils was adequate. You are correct that I ran a large main feed wire to the PC8. Coils are not carrying load all the time. They are switched on and off and just to illustrate it, if they were closed for say 120 degrees, effectively only one coil is drawing power at a time. I don't use points, I use a custom DYNA set up that draws a lot of power for a very short time and DYNA use tiny wires on their system.

With fat wires, you still put full power through the switches and with a relay you dramatically reduce the current flowing through the switch. That is reason enough to use a relay or three IMHO. Stock wiring worked for most people and I applaud you for rebuilding the harness and showing us the details. There are many different ways to improve on what was designed and manufactured in the 70s

I was thinking about the two gauges of wire in your earlier pictures. Was the oddball large one connected to the regulator as the voltage sensor by any chance. When I modified the wiring harness on mine, I found that the voltage at regulator input was consistently lower than the rest of the system which results in overcharging because the regulator "sees" a voltage lower than the battery. If that's the fat wire, perhaps Suzuki also realized that. If it's not, it explains a lot.
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