84 Sabre VF700S Electrical Issue

Hello!

Let me preface this a little, I'm an idiot, I can generally take care of mechanical fixes on cars, but for the love of god don't let me touch anything that's got a wire plugged into it under the hood, I need some help here.

This is my first post, this is my first bike, and if its NOT ok to post anything about the Sabre's here, let me know, this seems to be the closest place I've been able to find in getting help, no love for these bikes.

What I have here is a 1984 Sabre VF700S with 20,400mi on it, seems like a fantastic bike, I've certainly had fun toodling about with it, with few issues, but more on those issues later.

The issue:

I pulled out of traffic yesterday on the way home since the bike suddenly got hot, ran the revs up and got moving down a side street to try and cool it off, turned into a parking lot after that didn't do much, turned the bike off, and sat down. Fast forward 10 minutes and I go to start the bike, turns over twice and its dead, brand new battery, no go, had to get a jump after letting it cool down for an entire hour.

Today, I got home, took off the seat, put a multimeter on the battery and got 12.58V, healthy, started the bike, it started the instant I hit the button, checked the voltages at the battery around 2k-2.5k rpm when the choke was on, was getting around 13.5-13.75V, great! its charging hurray!

Thats when I noticed smoke coming from the multimeter, but it wasn't coming from the multimeter, it was coming from /under/ the multimeter, this connection!



Which lines up to the following in the Clymers manual:



Why are the wires from my alternator(magneto?) getting too hot to touch and melting this connector?

Is there is ground issue?

Can someone please take pictures of where the grounds are on this bike so I can replace ALL OF THEM if that might resolve the problem, and if someone is really just an awesome person and can assist someone dumb like me who can't easily sort out where all the ground wires might be?

... Help! Please!?

Also, if you are in the Sacramento area, and you can help me out with a few little things on this bike, might be able to make it worth while!

 

If you look a bit lower in your photo, you'll notice that the wires exiting the white connector are burned; I suspect that might be where the smoke was coming from.

I don't about the butt splice connectors that you circled with regard to whether or not they are stock; I suspect not, judging by the crimps. Regardless, the white connector is shot. Most people just get rid of the connector and wire the regulator directly to the alternator, which is probably the best thing to do. I would probably cut the upper wires above the existing butt splices, cut back the lower wires to the point of finding clean copper and non-crispy insulation, and splice in some new wire of the equivalent gauge (probably 12 or 10).

The reason the connector melted is that the connections became corroded. When that happens, they become an electrical load, i.e. a heating element. It's a pretty common failure.

 

I will do that tomorrow, soon as I can.

The strange thing to me really is that the entire wire from the alternator up till that point was just BLAZING hot, I'm surprised it wasn't melted all the way down to where its coming from. Thinking about it now, if there really is that much resistance at the single point where that connection exists, it sort of makes sense that the whole wire would warm up from that point back.

I'll replace it, see what happens.

Thanks!

 

I feel stupid again, about to go take the plug out and wire everything direct, but, does the order of the 3 yellow wires matter in any sense?

I'm not sure, the regulator should take the 3 phase power in any order from my thought on things, but then again, see above, if its on a motor vehicle and its got wires, I can, and will break it.

Thanks

 

It shouldn't matter, but I would label them and keep them in order anyway. Oh, be sure to use some quality heat shrink over the connections or seal the ends with some silicon RTV after you verify that everything is working the way it should. Moisture is usually what starts doing in high amperage connections.

 

Well, its ugly, not nearly as nice as I wanted it to be, but the connector is cut out, and the wires are joined, soldered together. The heat shrink tube I got from radioshack was totally worthless, absolute crud, I gave up on it and wraped each nice shiny soldered joint with electrical tape and gave it a sudo-shrink-wrap treatment with a butane torch. Not pretty, not how I wanted, but the wires stay mighty cool after this and the voltage to the battery while running seems to have increased a tid bit.

I was in very high hopes this would be the cause of the bike stalling out when its hot and at idle, however if anything it seems to have made it worse, least my crotch won't be in danger of bursting into flames while going down the road and that I can dig.

Thanks!

 

I soldered mine together years ago and have had zero problems since. Still have the original rectifier.