1986 aero nb50 ground wires melted

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Txaero121
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1986 aero nb50 ground wires melted

Post by Txaero121 »

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So picked up a my 86 aero 50 was checking everything over before my tires come in and new petcock so I can run it have not even gotten that far yet !. I was looking at the regulator/ rectifier actually was only looking at it to maybe snag a spare to have a extra on hand and noticed the green ground cable that hooks up to it was melted by the back taillights had melted. upon inspection I opened a good section of the harness up and the green ground had melted a good ways down where it stopped was about half way up from the floor pan around where the seat is another thing it did not pop the 7amp fuse located on the side of the battery box . i have no idea what the previous owner did with this scooter i got it for 100$ as is .

-The rectifier underneath it was a bit corroded I cleaned off the base of it with some sand paper along with cleaned the top where the ground mounts & the frame section under where it mounts bit and the bolt whole also just picked up a replacement copper lug for the green ground wire that connects to the rectifier/regulator
-someone on another site suggested the stator could be bad BUT i thought if the stator is bad it would not allow the bike to have spark .if i am not mistaken When the engine is turning over the flywheel +stator produce power that the CDI converts in the DC to send to the coil to cause spark at the spark plug .another suggested it could of been "ensure good ground everywhere.
bad regulator ground caused heat". i know it has spark i checked that 1st before i even noticed the melted ground
- i repaired the burn wires via soldering everything back .i just printed out the service manual to check the ohm readings with my Digital Multi-meter when doing this from what I'm reading the bike has to be on and running? or can i throw a battery in it and check like that.
I'm going to go through and check all the grounds any tips not melting the ground before i try and start this also any other insight on what to look for and where as far as grounds go .
mousewheels
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Re: 1986 aero nb50 ground wires melted

Post by mousewheels »

i just printed out the service manual to check the ohm readings with my Digital Multi-meter when doing this from what I'm reading the bike has to be on and running? or can i throw a battery in it and check like that.
No power should be applied for resistance measurements. Any power on the circuit would cause the measurement to be invalid.

Measure resistance as described in the manual. Components such as CDI, Regulator, Stator are un-plugged before resistance measurements. Else other components wired to them will cause erroneous readings.
-someone on another site suggested the stator could be bad BUT i thought if the stator is bad it would not allow the bike to have spark .if i am not mistaken When the engine is turning over the flywheel +stator produce power that the CDI converts in the DC to send to the coil to cause spark at the spark plug.
The stator has several independent coils. The Lighting and Charge coils may be good or bad, and you'd never see an issue impacting the CDI. Just check out your Headlight and that the battery charges when your scooter is back to running.
another suggested it could of been "ensure good ground everywhere.
bad regulator ground caused heat". i know it has spark i checked that 1st before i even noticed the melted ground
Bad ground or bad regulator ground I do not believe caused the melted wire, as the section of wire close to the ring terminal is intact.

The fact the insulation around the ring terminal and regulator is intact is because the terminal/bolt and regulator were cooler and acted as a heat sink.

Thus I'd guess it was an extreme high current fault - causing the wire to melt its insulation. That would be far more current that it takes to blow the fuse. It's also more than the stator could generate. I think the fuse was bypassed during the period of time the wire damage occurred. Everything could be fine now, as you are not reporting fuse issues.
Txaero121
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Re: 1986 aero nb50 ground wires melted

Post by Txaero121 »

Thanks for the input I will do those things here over the weekend . I saw on another page a guy had this happen when using a battery jumper , also saw a post i think on here about someone connecting the battery cables backwards who knows the life behind this bike previously..it was filthy dirty and not well kept i just know these parts should not be melting wires even if they go bad that would make no sense. ! I checked everything other than the regulator not 100% on how to do that via the chart and the process ,but the stator, resistor, coil where all in ohm spec . last thing I need to do is check the oil pump the old oil in the oil resi seemed to have turned into some goopy slime looked like tooth paste most was in the top tank and got caught at the filter but I don't trust it I wana pull the pump and clean it good then Well see if wires start melting again lol I cleaned all the grounds via wire wheel as well just to make sure.
mousewheels
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Re: 1986 aero nb50 ground wires melted

Post by mousewheels »

I checked everything other than the regulator not 100% on how to do that via the chart and the process ,but the stator, resistor, coil where all in ohm spec
This is my take on the test:

In Row 0/Col 0 is the text "-/+". That defines which DMM Probe (-) Black/ (+) Red used for each test. Runing the tests row by row is convenient:
  • Row 1: Connect Black Probe to "A", Iteratively connect Red Probe to "B, C, D", verifying each reading
  • Row 2: Connect Black Probe to "B", Iteratively connect Red Probe to "A, C, D", verifying each reading
  • ...same pattern for Rows 3 and 4...
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The reason the regulator test is complex is some readings vary due to meter polarity.
For example when testing terminals A/C:

Black (A), Red (C): Expected result = 0.5 - 10k ohms
Black (C), Red (A): Expected result = infinity ohms
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