Topic: Melted wiring - Help me find the cause?

[apehanger 550]

  +1 on the digital multimeter. I get my cheapo meters free at Harbor freight and use them where I do not want to risk the nice meter I have.
  You just never know about wiring ,including the colors. My bike had a black wire leading away from the voltage regulator,and I found out the hard way that it was actually a ground wire. Previous owner and all that rot.  I got off easy,because I was not running the bike ,but just trying to get the wire connections cleaned up.
  The regulator ground wire did not burn up,but two of the small diameter ground wires burned up from their grounding points toward the battery

[lucky]

It is common to see black ground wires.

Green or black.

[LesterPiglet]

It is common to see black ground wires.

Green or black.

But not on Hondas. 

[TwoTired]

It is common to see black ground wires.

Green or black.

Where?  That is the issue.  Care to guess what the black wires in house wiring do?

[LesterPiglet]

I must admit black was ground/earth on the old british cars I tinkered with but that's probably the last time I seen it.

[TwoTired]

I must admit black was ground/earth on the old british cars I tinkered with but that's probably the last time I seen it.

The point is, assumptions around electricity can get you killed, or damage more parts if you get it wrong.

Colors mean NOTHING to electricity.  They don't need no stinkin' colors.  You must know who assigned the colors, and what they intended to convey with those color choices.

Lots of low voltage stuff uses Black as the common or NEG return.  Sometimes, it is even an earth reference.  But, it is NOT ALWAYS the case.
Such assumptions can cost you, financially and physically.

I speculate that Honda maybe took cues from house wiring NEC code, where black is hot and green is earthed connection.

Other, manufacturers may have used a multicolored dart board, using amateur tossers.   

Cheers,

[adamlwvdc36]

Not sure we have the full story here... .... the bike will run with the battery installed backwards ( reversed polarity ) but the rectifier will short-out PDQ and melt wires as photos show.... and fuses wont blow as headlight/ignition/taillight circuits are not overloaded ( and will work fine if wired in reverse ). The clutch diode might melt some wires too, btw...... all = . The bike might run for 100 feet or so until the dead short on the battery pulls the voltage down PDQ below enough to make the plugs fire.
If you unplug the rectifier and pull the clutch diode out of it's holder, you can connect the battery backwards and everything on the bike will work as normal...no burnt wires or anything and you can ride away no problem until the battery dies as the battery won't charge.... , but otherwise no damage.

The shop manual says pretty much exactly this.  I know from personal experience when my polarity marks on my 550's battery wore off and I didnt run the bike for a couple of years... I went to jump the bike and put the polarity backwards...  needless to say, I had this EXACT thing happen to my bike... also shorted out and DESTROYED the Neutral safety device (also explained in the shop manual).  In this state the bike wont even crank... luckily for me (and maybe not for you) I had another 550 as a parts bike that I was able to harvest the entire wire harness... she runs good now and the harness only takes (me) about an hour and a half to replace.

[Blitzburgh207]

So bottom line is:  I reversed polarity somewhere along the way.  Correct?

Still waiting on my harness from Canada.  Who knows how long that will take.  And a BUNCH of parts from DCC that shipped 6 DAYS after I ordered them  .  But hopefully I can get to work on this soon.

Thanks again.

[apehanger 550]

So bottom line is:  I reversed polarity somewhere along the way.  Correct?

Still waiting on my harness from Canada.  Who knows how long that will take.  And a BUNCH of parts from DCC that shipped 6 DAYS after I ordered them  .  But hopefully I can get to work on this soon.

Thanks again.

  I saw it mentioned somewhere that a big box store sold some [pre-charged] MC batteries that were reverse polarity. I usually buy dry charged,but now I will be checking any battery that I buy in the store with a multi-meter

[adamlwvdc36]

So bottom line is:  I reversed polarity somewhere along the way.  Correct?

Still waiting on my harness from Canada.  Who knows how long that will take.  And a BUNCH of parts from DCC that shipped 6 DAYS after I ordered them  .  But hopefully I can get to work on this soon.

Thanks again.

  I saw it mentioned somewhere that a big box store sold some [pre-charged] MC batteries that were reverse polarity. I usually buy dry charged,but now I will be checking any battery that I buy in the store with a multi-meter

AMEN to that man