I ma trying to get an old 750GT started that has not been run since 1985.
I am installing 5ohm Dyntek coils to go with the dyntek elctronic ignitoin. HOWEVER - as I look under the tank I see 3 wires coming out of the wiring harness in the area near the coils. One wire is white and the other two are conected together one being green and the other being blue.
I do not see any of these wires on the diagram in my "instructions for use and maintenance".
I think that one (or both?) are the power leads for the coils. But which one?
The wiring diagram shows one verde scuro (dusk green) wire going to one coil and then a piggy back wire giving power to the other coil.
Any help out there?
Larry
750Gt Extra wires
Extra white wire
I'm working on a 1973 750GT and came across the same question. Here's what I've worked out. Note: This only applies to my bike! As we know, no two seem to be the same.
1. There is a two-wire harness with one black wire and the other...dark green?...dark blue? These go from the terminals marked "1" on the coils to the points inside the engine.
2. From the fuse box, there is a bright green wire that runs to the terminals marked "15" on the coils. It pigtails at one terminal connection so it can also attach to the other coil. This is the 12V "+" side of the ignition.
3. Also attached to the "15" terminal at the same pigtail point is a blue wire that runs up to the dashboard and eventually attaches to a bulb that indicates the ignition is ON.
As to the small white wire: Near as I can figure, that wire is used for an electronic tachometer as was fitted to some bikes. (Mine has a mechanical Vegalia.) I suspect the wiring harness was built to accomodate all variations. It attaches to one coil on the points-side (the "1" terminal) and runs up to the dash. On my bike, it has a shielded female spade connector that connects to nothing in the dash...it is just loose in there. I put some heat-shrink totally around it to be sure it never shorts against anything, which one person reported happening on the BevelHead mailing list.
Hope this helps. If you have any other questions about the wiring, feel free to contact me, since I've been through mine pretty thoroughly and feel I understand how it all works.
1. There is a two-wire harness with one black wire and the other...dark green?...dark blue? These go from the terminals marked "1" on the coils to the points inside the engine.
2. From the fuse box, there is a bright green wire that runs to the terminals marked "15" on the coils. It pigtails at one terminal connection so it can also attach to the other coil. This is the 12V "+" side of the ignition.
3. Also attached to the "15" terminal at the same pigtail point is a blue wire that runs up to the dashboard and eventually attaches to a bulb that indicates the ignition is ON.
As to the small white wire: Near as I can figure, that wire is used for an electronic tachometer as was fitted to some bikes. (Mine has a mechanical Vegalia.) I suspect the wiring harness was built to accomodate all variations. It attaches to one coil on the points-side (the "1" terminal) and runs up to the dash. On my bike, it has a shielded female spade connector that connects to nothing in the dash...it is just loose in there. I put some heat-shrink totally around it to be sure it never shorts against anything, which one person reported happening on the BevelHead mailing list.
Hope this helps. If you have any other questions about the wiring, feel free to contact me, since I've been through mine pretty thoroughly and feel I understand how it all works.