Electrical Issues

I know how people love electrical issues. I'm just wondering if anyone has had this issue, or has any ideas on how to solve it.

I have an 81 seca 750. Bought it from my boss, who had the bike sitting around for about 2 years. He said he had the bike running, but kept blowing a fuse, I think he said the headlight fuse. After he tinkered with it, it sat for those 2 years. Duing that time it sat outside under a tarp then in a barn. I bought it for cheap and have started to work on it now.

First thing I'm trying to do is to see if it will turn over. I hooked up a battery and all I had was the brake light came on, along with the back lights for the gauges. I had no other lights, and if you hit the brake pedal the break light did NOT brighten up. I figured the first thing to do is to change the fuse box. After replacing the fuse box the brake light now gets brighter when hitting either brake, and the turn signals turn on, but don't blink. As for the gauge center. The warning light is on, and all the items on the LCD display are on and don't turn off. The Fuel gauge works though. I have no headlight or aux light, and the highbeam low beam switch isn't doing much. I did hook up a volt meter to the headlight plug and had four volts, then when I would put it in high beam i had not voltage anywhere. The horns don't work, and I don't think i had voltage there when I would press the button. If you turn the run switch on you can see the tach needle jumps a slight bit. I don't know if I have relays that are bad, or if the control center is bad. I've checked all the fuses, and they all look good. I don't have my Haynes manual yet, but it should be here by the end of the week. I found a wiring diagram, but it isn't as specific as I was hoping it to be.

If anyone has any ideas or input it would be greatly appreciated. I'm going to school right now for electrical engineering so this stuff isn't really a pain to me, but I'm just curious. I have only spend about 2 hours with a volt meter on it.

 

Welcome to the site, and good move on replacing the fuse box!

The headlight and aux light may not come on until the engine is running, my '82 is like that.

Things to check on the signals are at each light bulb connection internally, the short pigtails that connect under the seat and in the headlight housing and of course the grounds. Make sure there's no rust/corrosion build up causing a voltage drop. In general you should be checking as many connections as you can in your wiring harness to verify good contacts.

The computer display is designed to show what's not working. The XJCD does have a section on the computer. When I was rebuilding my bike I was sure happy to check off each computer monitor as I went. I had bad bulbs, bad connections, and no battery sensor ( which I did locate one in my boxes of parts ).

You can look here for electrical diagrams, looks like copies from the Haynes manual .....
http://members.tripod.com/dave_jack/id39.htm

So start one section at a time and work thru them! If your computer is working it will tell you when it's happy with the wiring and connections.

 

Pull the Starter Motor
See if the Starter Motor will Operate by connecting 12V to the Pigtail and Case to Ground.

Pull the Left Side Crank Case cover and all 4 Spark Plugs.
Place 1/2 Ounce of Marvel Mystery Oil in each Spark Plug Hole.
Using the Square Flats on the end of the Ignition Rotor ...
GENTLY ... Jack-over the Engine using a wrench on those Flats.

Rock the Crank ... back and forth to spread the lubricant.

Then, Turn the Engine in the direction of the arrow on the Rotor for at least

8 Full Revolutions.

 

I think i have a bad neutral sensor or something. I have no neutral light when it is in neutral, so in order for me to get it to turn over I had to have the stands up and have the clutch pulled in order for it to turn over. Once I hooked up a gas tank the bike started right up but would only run for a few seconds. I have to rebuild the carbs, but I'm happy that it ran. Now I get to dismantle the bike and clean everything and repaint things. I'll add some pictures to my gallery sometime. Thanks for the advice.

 

Gummy, test your neutral switch by grounding the wire. If the light glows, the switch is bad. Otherwise, your chasing the wires.

 

Grounded wire and the light came on. Now it is time to take the carbs off and rebuild them, and clean the rest of the bike. I think we may pull the engine off the frame and clean the frame up. Thanks all for the help.