Topic: rectifier wire melted. Common causes?

[gecko672]

CB750 K1

I know there are a few threats on replacement rectifiers, and I have read the post about building one yourself, but I may or may not need to replace mine. I noticed that the red wire from the rectifier has at some stage gotten  hot, the plastic insulation has deformed and in one area melted through to expose the wires. the other wires are fine and everything else visually looks perfect with it.
I havent tested anything on it yet and will do. Just was wondering what could have caused it? is this a common thing?
I dont want to put it back in my system unless I can work out why it did this. What are some of the places I should check up stream or down from the rectifier?
If the rectifier checks out could I shrink wrap the wire and reuse it?
The bike was non running when i got it and has not run yet.
The old wiring harness was a mess of splices and connectors, I have a new oem wiring harness and fuse box.
Cheers

[bollingball]

I think at one time someone hooked up the battery backwards Or when using jumper cables hooked them up backwards. Ken

[gecko672]

Interesting..would that also damage the rectifier?

[TwoTired]

I think at one time someone hooked up the battery backwards Or when using jumper cables hooked them up backwards. Ken

Agreed.
Another likely rare scenario, is that one or more rectifier diodes fails in the shorted mode.  This would, in effect, connect the stator coils directly to the battery with very little resistance to current flow.  If this occurred the yellow wire insulation would melt as well.

Replacing insulation on wiring is a given.  However the wire itself got pretty hot and may have melted some strands within it, or diminished the integrity of the terminals crimps.  Kind of a judgement call, here.  I'd closely examine the crimped terminal ends for damage and the advancement of corrosion.  If you have access to the same wire type as was originally used (very high strand count), then replace the entire length damaged segments, and any terminals/connector in the fried path.

I'm not saying it can't work with band aid path up.  But, the long term reliability is certainly at risk.

Further, if the red wire cooks off, the Green ones usually do as well.  Follow and check that path for integrity all the way to a solid frame connection.

Cheers,

[Davidov]

Further, if the red wire cooks off, the Green ones usually do as well.  Follow and check that path for integrity all the way to a solid frame connection.

Cheers,

I just dealt with a melted Green (ground) wire. I ended up cutting out the complete section.

[bollingball]

Further, if the red wire cooks off, the Green ones usually do as well.  Follow and check that path for integrity all the way to a solid frame connection.

Cheers,

I just dealt with a melted Green (ground) wire. I ended up cutting out the complete section.

You miss quoted.

[gecko672]

yeah the yellow wires look perfect, the green had a tiny area of wire showing  ( just 1 strand of wire wide about 1mm long) this looked more like  friction with the yellow wire than melting. But your right Im not really into band aids on this project.
Since I have never heard this bike run, and its a total frame up rebuild I may just have to replace the rectifier for peace of mind come time to get her fired up. I've been looking at the Z1 regulator and rectifier combo for $99. It looks like it already has the right connectors and just needs to be positioned.  or oregonmotorcycleparts.com

any opinions?

[TwoTired]

If the diodes measure properly on the test meter, I'd be inclined to just replace the bad bits and keep the rest in service.
But, I have a personal problem of throwing anything away that is still good or salvageable. 

I've been accused of "hoarding" because of that.  But, I'm not your model consumer that happily replaces what was thrown away last year or last week.  I also fix or make a lot of things without a trip to the store.
I think I inherited my mother's WWII save everything, mend everything, ideology.
But, I digress...

Cheers,

[gecko672]

Well, Im essentially the same, but electrical is something Im not very good at. I love the mechanical. I see how it works and I can wrap my head around it. When it involves electrons I cant see, doing things inside stuff that doesn't move, I get a little lost . Everything else Ive fixed, repaired and reused. 

[TwoTired]

I started out with the mechanical, cause I could see and lay hands on the physical (physics) operation.
Turns out electrical uses the same physics principles, and to "see" what it does just takes an instrument to display what's going where and when.

I speculate that carbs have a similar mystery for people because they cannot see what it does in operation.  The movement of the fuel and the air is invisible to them.  And, they can't imagine what's going on inside with only the physical things they can see that move.
Fuel flow and air flow are similar in conceptual movement as basic electron flow.  Some of it can get quite complex if you delve into the innards of either machine or electronics.  Nearly ALL electronic repair work is physical in nature, (unless you are doing innovative design work).  But, in a bike like ours, if something electrical doesn't work, it is almost 99% assured that a physical, mechanical device has failed, even if it is a silicon junction inside a diode.  All the electrics on the bike need mechanical bridgework to get from one point to another.

zzzzzzzzzzzzzzzzz....

Oh...
Cheers,

[Jerry Rxman Griffin aka MuthaF'er]

If the diodes measure properly on the test meter, I'd be inclined to just replace the bad bits and keep the rest in service.
But, I have a personal problem of throwing anything away that is still good or salvageable. 

I've been accused of "hoarding" because of that.  But, I'm not your model consumer that happily replaces what was thrown away last year or last week.  I also fix or make a lot of things without a trip to the store.
I think I inherited my mother's WWII save everything, mend everything, ideology.
But, I digress...

Cheers,

TT,

Do you have one of those thing a ma jigs that fits inside a sock so you can darn the heals of socks when they wear thin?

[TwoTired]

TT,

Do you have one of those thing a ma jigs that fits inside a sock so you can darn the heals of socks when they wear thin?

No...

Where can I get one of those?   

What I need more is an elastic rejuvenator...  To keep the ones without holes from falling down and gathering at my toes.