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Ok, I am beyond pissed. I'm restoring an 86. I have not done any electrical work on the bike yet. I replaced the battery,Yuasa maintenance free battery. The bike worked with the old battery, as well as the new one. I go to fire up the bike and it wont turn over, so i remove the seat, and lo and behold the the F*&KING negative contact on the battery is melted off.

Please help me figure out why this has happened. I am about kill something...:BLAM:
 

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Ok, I am beyond pissed. I'm restoring an 86. I have not done any electrical work on the bike yet. I replaced the battery,Yuasa maintenance free battery. The bike worked with the old battery, as well as the new one. I go to fire up the bike and it wont turn over, so i remove the seat, and lo and behold the the F*&KING negative contact on the battery is melted off.

Please help me figure out why this has happened. I am about kill something...:BLAM:
Is it possible that it wasn't tight, or loosened off a bit?

More resistance (bad connection) will cause more heat.
 

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Excess amp draw from the starter or cranking too long and overheating the wires. Those are two ways to do that.
 

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Discussion Starter #4
I cranked it maybe 5 sec. Piss me off, I'm out $100. My wife just told me "Forget trying to restore it, just go buy a new bike". I'ts now personal. I wish money grew on trees.
 

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..have a vulcan good day!
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I cranked it maybe 5 sec. Piss me off, I'm out $100. My wife just told me "Forget trying to restore it, just go buy a new bike". I'ts now personal. I wish money grew on trees.
I would attempt to come up with a jeri-rig of cable attachment.

Clean Starter Positive connection and all battery-frame grounds.

:smiley_th
 

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Having a similar problem. Bike was running fine on flooded battery... Put in new agm and as I screwed in the positive the negative wires started melting... No clue what just happened!
 

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Negative terminal melted off too
 

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1986 VN750
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I would check all ground connections. Maybe disconnect them, clean the contact area, and re-affix them.
 

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Prowling Tiger
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Yikes! I wonder if there was a short somewhere and the terminal got too hot. That's the only thing I can think of, a short.
 

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Yikes! I wonder if there was a short somewhere and the terminal got too hot. That's the only thing I can think of, a short.
That's what happened with mine... Poor insulation on the positive wire created a ground to the frame :/

Shaggdog that battery should still be good. Test it to make sure it's still putting out juice and just rig up a new connection. Mine was not as bad as yours but I was able to mold the lead with a heavy duty soldering iron. But obviously you need to find the source of the problem first. If it works with the other battery I would think you also had an unintentional ground somewhere. Are you sure it was fine until you tried to start it? I.E. didn't already melt before that?
 

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I've never seen a loose ground (or positive) cause a terminal to melt, or even slightly warm up. If it's loose, it's not going to carry the amps.
 

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Sparky!!!
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I've never seen a loose ground (or positive) cause a terminal to melt, or even slightly warm up. If it's loose, it's not going to carry the amps.
I have seen too many batteries melt down due to a bad ground (never heard of it happening on the positive side though due to a bad connection) Here are two I have seen recently... I also have 4 more pics I can post tomorrow after I pull the batteries out of the truck I am working on. It is actually very common with a bad ground.


 

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How do you determine a bad ground caused the meltdown?

How did I manage to avoid this very common problem in the thousands of battery connections I've dealt with in the past?

How is it a loose ground can roast a battery into a puddle, but can't deliver enough amps to turn a starter?
 

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That would be known as a dead short. 100% of the battery's available amps going right back into itself. I don't see a loose ground connection turning into a dead short.
 

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Sparky!!!
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I know its called a dead short.... try this.... take off the negative battery cable, unhook the r/r and ignition box. Then turn the key on. Touch the battery cable to the frame. Watchnthe sparks fly and feel the cable get warm.

Sent from Motorcycle.com Free App
 

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It's not really from a loose ground, it's from an unintentional ground. In my case yesterday, thin insulation on the wire from the positive allowed the spark to burn through the sheath and the power grounded through the frame. Power went through the frame, up the ground wire(connected to the frame) to the negative terminal... Essentially connecting the positive terminal to the negative terminal of the battery. I got lucky as I was able to rig an attachment to the remains of my melted terminal and the battery still works great.
 
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