Help reading 78 GL1000 color schematic

[EdK]

Hi,
I need some help understanding this schematic:

1978_79_GL1000_Colour_Schematic.jpg (149.92 KiB) Viewed 344 times

As I said in another thread, I am in the process of replacing the harness. In the upper right corner of the schematic, there is a 6 pin connector, just below the coils. This is the black connector that plugs into the box with the diodes behind it. I can see the 4 wires connecting to the coils, but I don't know what the other two wires (black, brown/black) running to the resistor do. On my bike these are cloth insulated. One of these wires is broken, and one connects to an orange wire which is jury rigged . At any rate, I don't see that resistor anywhere. Does anyone know the location of the resistor, and what it's purpose is?

Thanks,
Ed

[Whiskerfish]

Ballast resister should be mounted to the side of the Coils. Without that two wires connected you will never get spark

[Whiskerfish]

Large white ceramic heat sink mounted to it.

[pidjones]

The ballast resistor is mounted between and behind the two coils on a '78. Its purpose is to reduce the current consumed by the coils when running (helping the coils run cooler). The resistor is bypassed when starting to give a hotter spark, (Start button pressed). It is about 4 inches long and about 3/4 inch square and is rated at 3 ohms.

[EdK]

Thank you!

[Shadowjack]

The ballast is actually in there to keep the points from burning out so quickly. The coils are made to deliver full rated power at about 9-10 volts, because that's what the battery delivers when the starter is cranking. Once the system goes back to 12-14 volts, the points are conducting too much current and burn fast. So the ballast is switched in once you release the starter button.

[EdK]

Here's what I'm seeing:

I don't see a resistor mounted on the coils:
Left Coil:

Left coil again.jpg (61.4 KiB) Viewed 296 times

Right Coil:

Right coil.jpg (47.54 KiB) Viewed 296 times

Here's the broken wire I believe is supposed to go to the resistor:

Broken wire supposed to go to resistor.jpg (52.52 KiB) Viewed 296 times

Here's the other wire supposed to go to resistor, but rewired back into the white/green and light green wires coming from the harness, that I believe feed the fan temp switch:

Resistor wire fed back into light green and white-green wires from harnes.jpg (52.15 KiB) Viewed 296 times

It looks to me like I don't have a ballast resistor and there was some kind of workaround. The bike was running and starting fine before I had the fatal short. I'm unsure of myself when it comes to this stuff, so I'm looking for advice on where to go from here. This is the last issue before I install the new(used) harness.

Thanks!

[desertrefugee]

The ballast resistor is long gone off my '78 (Dyna ignition), but a glance at the schematic shows a black wire and a brown/black as going to the resistor. The bike will run fine without it, but as noted, you'll go through points quicker and the coils will run a bit hotter. Some folks have done this to yield a little hotter spark. (Probably easier to dink with plug gaps)

If you want to put it back in, it goes in the 12V line that's common to both coils. The other side of the primaries are driven to ground through the points. Running without the resistor, you'd simply join the black and the brown/black wires together.

[Whiskerfish]

Those are not stock coils. Stock 78 coils do not have removable plug wires.

[heraldhamster]

Those are not stock coils. Stock 78 coils do not have removable plug wires.

good eye, boss!

they are stamped with something on the side and the molded exterior resembles a DYNA coil but they're seemingly black and not the green 3.0 ohm rated for a GL. might be wrong ohm rating (5.0 ohm possibly, based on color and IF it's a DYNA) for our bikes but also shouldn't need the ballast resistor for proper operation (it seems).

[EdK]

Interesting.... definitely running points.

[robin1731]

Those are 5ohm coils. You can just make it out in the 2nd pic. They probably put those on and eliminated the resistor. But then the wires to the resistor need to be connected to each other. There looks to have been some "creative" wiring done in there. Look close at the diagram and close at what you have. Following wires to see where they go.

.

[EdK]

FYI, I took a closer look and they are stamped "Dyna Coil".

[EdK]

Another question please:

I want to test the diodes located behind the junction box. So I pulled them and checked for continuity by placing my multi-meter probes directly on the diode leads, and checked for continuity - both ways. I have two on my original harness and two that came with the new used harness, and all 4 do not show continuity. Am I doing this right? Does this mean they are all bad? Before my fatal short the neutral light was working fine.

Thanks!
Ed

[desertrefugee]

Should be open in one direction. Reverse the leads and check again, i.e. the other direction. Most diodes will then read anywhere from 700 to 1500 ohms when forward biased. So have the meter in the 2k range.