loss of electrical power

I lost all power to my 1981 yamaha special II. No lights or ignition. What could it be?

 

Welcome to the site mustangc78, kinda vague question....

Dead battery
Bad or loose connections
Blown Fuses
Bad Fuse block
Poor Ignition switch connections (external or internal)

 

I agree with Nick. Would need more info on it.

 

well i had it running and i was making adjustments on the carb because it has been running rough. and then it shut off and i lost all electrical power

 

Welcome MustangC, I'm going to hazard that you have a loose/corroded connection on the battery or ground cable. This is merely a guess given the description you have provided but it wouldn't hurt to look into your fuse box either. Let us know what you find. If your still stuck, let us know what works, what doesn't and what you have done in the investigating effort.

 

ok, I have checked all fuses, I replaced my ground wire and checked the power wire. I tried jumping it off of another battery with jumper cables. And I still get no power at all. NO lights, horn, turn signals or ignition. I followed the power cable coming off of the battery and it connescts to a junction box with two terminals on it, and also 3 smaller wires coming off of it that run to the handle bars on the bike. The power cable conitinues past that junction and goes to the lower part of the engine where it says 12volt generator. I tried putting power to the cable after the junction and the bike turns over but does not start. because there is still no power going to the ignition.

 

I have a 30 amp main fuse on mine under the seat. If you blow that fuse it will kill the bike lights, ignition and all.

 

I'm not familiar with the Specials but electricity is universal. Earl-R, sounds like you have some experience with the layout of this XS. I hope your advice helps get Mustang back on the road.

 

ok, Is that the fuse thats right behind the fuse box under the seat? I believe it says lighting relay on it... Is there a way to test it because it is solid plastic, and where can I get one to replace it?

 

go buy a simple multimeter (like walmart has them for $15), and test from battery to fuse box, et al, and find what is not working.

 

Another thing that I was having problems with, when it was running was that the idle wasnt steady, it would fluxuate between 2,000 and then down to 500 and sometimes stall out. and when I road it down the road it was surging and would back fire. I started to adjust the screws on the top of each carburetor which is the air fuel mixture screws and it didnt seem to get any better. But thats when I lost all power to the bike and haven't been able to get it running again. The funny thing is that for the first month of the summer it road great and then I took it out one day and it started to back fire, and it has gone down hill since then.

 

Here's a question. When you say no lights, do you mean no headlights, or no lights anywhere on the bike? If you have lighting (speedometer, neutral light indicator), then does it at least click when you press the start button? What do you mean by "no lights"?

If you have nothing at all, then you need to test connections w/a multimeter. Simple way to find where the issue is.

 

I have no power at all, Lights, ignition, no neutral light, no turn signals, no horn, everythings dead. Even when i jump it off another battery.

 

Check your ground cable at the batery follow it back to the engine case and check that conection.

 

Yeah, something is not connected. Could be your ground connection, but if you can't tell what's where, get a multimeter to test and find out... Easy way to fix it, and something you will need many times in the future.

 

I did check it, and I also grounded it out with another cable just to make sure. still nothing

 

I go out on a limb and say you have something wrong with the contacts in the Ignition Switch.

Test the wires going INTO the Ignition Switch Pigtail with a Test Light.
If you have 12V present ... then, test the wire From the Switch.
If you get 12V ... there's some additional troubleshooting to do.
If those wires aren't +12V -- Switched -- depending on the Position of the Switch ...

Your Ignition Switch has gone bad!