Wire harness repair/restoration

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

Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan

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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

About your point relating to the gauges for the two orange wires, Suzuki made a very big mistake there. The one orange wire I showed at the main midjunction connector was the bigger gauge, but it only fed the rear section of the harness for rear brake switch and the indicator relay.
The other smaller gauge orange wire I also showed is in the small midjunction nine cavity micro socket feeding the three coils and the voltage regulator at the very end of that wire.
Its not difficult to see the coils and the regulator are going to have a serious voltage drop in this situation.
Lets look at this power feed wire laid out in stock form. A single 16 gauge wire from the ignition switch goes into a branch tap for powering the horn, lights, instruments etc, from that tap an 18 gauge wire leaves and goes out to the kill switch and then back to the main harness.
Once back it heads to the rear section where it has to go to the micro socket in the main under tank junction connector AND then split to the three coils and finally to regulator.
So with this small gauge wire design its not uncommon to measure voltage at the coils and find just a tad over 10 volts, same thing or worse at the regulator.
As you mentioned, the regulator tries to compensate and overcharges with the lower input sensing voltage.

Also the ignition switch on the 750 is a poor design, the 550 and 380 switches have a pair of switched contacts you can use to your advantage. Using one of those switches on the 750 you can put the coils and regulator on its own separate ignition circuit, and the rest of the electrics such as the horn, instrument bulbs and brake lamps etc on the other circuit.
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
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tz375
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Re: Wire harness repair/restoration

Post by tz375 »

Allan has made the point about crappy connections, including the main 3 round pin connector. I am rewiring a stock GT750 M/A and I had an intermittent fault as I tested circuits one at a time. So I started to wiggle wires etc to identify the problem and that 3 pin connector was getting warm with only a light load.

Many replacement connectors look sturdy enough but when I checked on the wire gauge that they are suitable for, they were mainly in the 22-18 gauge range and that's too small, so I went with a 1/4" for 14g which should just about do the job and now I'm going to splice in a couple of relays to reduce load on switches.

Thanks Allan. :up:
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Good you caught that resistance issue Richard, Looking at that main harness three pin connector under the tank, you will notice its the same design as those used on the first gen GS750 handlebar light switch harnesses.
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 was lucky that the lights went out momentarily when I was testing things and that led me immediately to that socket which you had pointed out and with just the front end lights on it was getting warm to the touch. I didn't check the amperage rating of that style of socket, but it looks pretty marginal to me.
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tz375
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Re: Wire harness repair/restoration

Post by tz375 »

Allan,
I have been sorting through a pile of harnesses and it took me a while to work out that J/K points lead was 4 connection (3 points plus neutral) and later models had 3 leads to the points (neutral is now in the gear indicator loom) and that Suzuki left 2 blue leads in the rear harness.

One blue lead pops out in the side cover to connect to the gear indicator loom and the one in the points socket is still there. So I removed that from a custom loom. Then I removed the redundant fan relay and thermo switch leads and cut into the orange lead that goes to the coils and regulator and spliced a relay in there and spliced a red 12V lead from the 3 pin plug to the relay.

Next step is to replace that redundant blue lead with an orange supply for the Newtronics and I'll plug that into the old points socket. That eliminates the ridiculously long Newtronics flying lead to the coils and makes it simple to go back to points if necessary.

It wasn't immediately obvious to me that there are 2 orange leads going back towards the rear. One is switched by the Run-Kill switch that goes to coils and regulator and the second feeds every other circuit at the back end. With the coil/regulator now getting its feed from mid harness and avoiding all the connectors and switches on the power side, maybe we'll have a better feed to the charging system and better regulation as well as stronger sparks.

I'll let you know how it goes.
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tz375
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Re: Wire harness repair/restoration

Post by tz375 »

Quick update. That lifted the voltage at the rectifier from 11.4 to 12.4 if it's warm enough tomorrow to open teh garage doors I'll run it and see what the regulated voltage is like at the battery.
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

If you look at the two oranges going to the rear of the harness you will see the bigger gauge wire of the two goes to the rear brake lamp part of the circuit, you might want to consider swapping it over to the regulator wire and vice versa.
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 »

Two photos showing the before and after internal switch wiring upgrade.

Image

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 »

Heres a few photos showing three ignition switches for GT750s I've restored and upgraded to work with the updated wire harnesses.
In the large three pin socket is an orange wire in each lower cavity and a pair of red ones in the upper. The red pair split the battery input at the socket into two switched circuits inside the switch, which means this switch also has two seperate switched outputs, being its got two independent orange powered wires. The brown wire is park and the gray wire the instrument lights. You have to get these connectors through the hole in the ignition switch bracket so sizing is somewhat resctricted. All of the red and orange wires shown are now 14gauge 18 strand copper.

Image
After some re-engineering these switches are now how I want them to be.

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No key tumblers are fitted at this time to the switch barrels.

Image
Wiring on assembled/restored ignition switch before sheathing and the cover is fitted.
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 »

Restoring/upgrading the alternator.

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As it was when removed from a spare engine I bought.

Image
There is nothing good looking about this old alternators appearance.

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I cut the three yellow phase wires off and cleaned the stator winding assembly first.

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I also cleaned and resprayed the rotor. The commutator rings were lightly dressed in my lathe then I tested them, thats why there are carbon marks on the rings.

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Now to fit the new wires and sheathing.

Image
Now looking like new again with a renewed cover, new sheathing as well as upgraded 14 gauge wires.
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 »

Rectifier restoration/rebuild, in this case one diode pack was bad and so I used another one from some other spare parts I had to make this one servicable.

Image
Media blast the old paint off the diode/heatsinks.

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Two of the heat sinks now painted, I covered the terminals and used that area to hang them by.

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All new 14 gauges wires and a slightly revised wiring layout on the terminals.

Image
New wires, new sheathing and a new socket and terminals. At this stage you can touch up the soldered areas with black paint if you wish.
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 »

Here are some new wiring loops for the electrical panel, as well as a photo showing the updated section at the rear of the harness. Again new 14 gauge wiring was used for all of the important circuits in this section.

Image
New yellow and green wire upgrade to improve current flow for the charging circuit, this is way better than the wimpy factory wiring.

Image
The back portion of an upgraded harness, notice the new gauge of wire size in the three sockets in the centre of the photo. The regulator socket, the rectifier socket and the alternator socket connection.
They are all now 14 gauge, with the battery red one being a 12 gauge wire.
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 »

I use points on a few of my Buffalos and have no issues with them. To upgrade the wires meant I needed new flag terminals which seem to be hard to find, so I made my own. Remember to orient the terminals correctly as the one on the white wire goes on opposite to the other two.

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Brass stock from K&S, its the exact width and gauge

Image
A terminal after being roughed out.

Image
New 16 gauge wires added to the home made flag terminals.

Image
Yellow band simulates the black with yellow stripe wire.
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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jabcb
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: Wire harness repair/restoration

Post by jabcb »

Suzsmokeyallan wrote:...
Also the ignition switch on the 750 is a poor design, the 550 and 380 switches have a pair of switched contacts you can use to your advantage. Using one of those switches on the 750 you can put the coils and regulator on its own separate ignition circuit, and the rest of the electrics such as the horn, instrument bulbs and brake lamps etc on the other circuit.
A improvement to consider is to use two fuses with the GT550/GT380 ignition switch.
This isolates the two circuits, and the bike will continue to run if you have a problem with the lighting wires.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
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Suzsmokeyallan
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Re: Wire harness repair/restoration

Post by Suzsmokeyallan »

Yes agreed, and these compact in-line fuses are something to consider. They allow easy compact placement inside the headlamp bowl for independent fusing for the head lamp filaments as well as ignition circuit and others.

http://www.ebay.com/itm/271581000188?_t ... EBIDX%3AIT" onclick="window.open(this.href);return false;
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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