New rectifier issue on my 81

[81-twin-power]

Purchased new rectifier / and noticed the black and green wires are reading opposite from my original

 

[Jan_P]

There are different types
Pre 1980 and after I believe ( It can differ a couple years little )
But most likely you got the Wrong one

 

[81-twin-power]

There are different types
Pre 1980 and after I believe ( It can differ a couple years little )
But most likely you got the Wrong one

I had a hunch it was wrong, I read the black lead on my old unit and it was blocking as it should, but the new one had no reading, until I tried it on the green wire, then it was blocking as it should. It’s like the green and black wires are transposed on this new rectifier. Thank you for the update.

 

[81-twin-power]

I had a hunch it was wrong, I read the black lead on my old unit and it was blocking as it should, but the new one had no reading, until I tried it on the green wire, then it was blocking as it should. It’s like the green and black wires are transposed on this new rectifier. Thank you for the update.

Also one more question? Who would have the correct fit without issues?

 

[Jan_P]

Also one more question? Who would have the correct fit without issues?

Mikes XS in Florida should have something .But I am in Europe so I don't know the best deal over there
e -bay also. Should have something
I once ordered wrong the other way .. got the new model for an old bike --. from China
There are other solutions as well
Perhaps find solutions there
http://www.xs650.com/threads/regulator-rectifier-conversion-again.49964/

 

[Jim]

Have a read here.

 

[5twins]

What do you mean by "it was blocking ....." ? You may have the correct unit but it just might be defective right out of the box. Many of the aftermarket units are low quality and expensive. Best solution is to build your own like in Jim's link.

 

[81-twin-power]

What do you mean by "it was blocking ....." ? You may have the correct unit but it just might be defective right out of the box. Many of the aftermarket units are low quality and expensive. Best solution is to build your own like in Jim's link.

What do you mean by "it was blocking ....." ? You may have the correct unit but it just might be defective right out of the box. Many of the aftermarket units are low quality and expensive. Best solution is to build your own like in Jim's link.

The black wire reads on my older unit, when blocking as in one of Jim’s video I saw on You-Tube . When connecting the meter on the new unit No reads on the black wire , but I tried it on the green wire and Presto I got a read . It’s like they are transposed. On the new unit.

 

[5twins]

I don't understand what you mean by "blocking". When testing electrical connections, that's not a term I'm familiar with. The black wire is the ground wire. I don't think you get any reading on it. The green wire is the output from the regulator to the outside brush. In the case of your later alternator, that would be a switched ground signal. The regulator switches the ground on and off to the alternator to control the charging output. I don't know if you'd get any reading on the green wire unless the unit was powered up.

Why are you changing this out? Did the bike stop charging?

 

[81-twin-power]

I don't understand what you mean by "blocking". When testing electrical connections, that's not a term I'm familiar with. The black wire is the ground wire. I don't think you get any reading on it. The green wire is the output from the regulator to the outside brush. In the case of your later alternator, that would be a switched ground signal. The regulator switches the ground on and off to the alternator to control the charging output. I don't know if you'd get any reading on the green wire unless the unit was powered up.

Why are you changing this out? Did the bike stop charging?

Yes the bike stopped charging , to the point where the new battery went dead, motor just stopped, I just purchased the machine a month ago here in Cincinnati. I checked the alternator rotor with it on the bike / making sure not to touch the stator housing for false ohm reads on the copper rings. It showed up at 1.7 ohms - I removed both brushes when doing this procedure last night. I thought for sure it was the rectifier unit, but the brushes are low I’ve noticed. I retested the old rectifier and it’s showing good, I purchased the new rectifier without doing Good research on this new forum I just joined.

 

[Jan_P]

Keeping it simple
You could also publish part no and where you ordered the one that is under suspicion.
Perhaps picture of Invoice or documentation.
Perhaps we can google it ..

 

[GLJ]

. It showed up at 1.7 ohms

1.7 is bad, should be around 5 Ohms.
@Jim can advise you where to get your rotor rewound. He does good work.

 

[Jim]

1.7 is bad, should be around 5 Ohms.
@Jim can advise you where to get your rotor rewound. He does good work.

Thanks Greg.

Yes, 1.7Ω's is bad. If you want a rewound rotor, have a read here.

 

[81-twin-power]

Thanks Greg. View attachment 186661

Yes, 1.7Ω's is bad. If you want a rewound rotor, have a read here.

Good afternoon Jim, thank you very much for the detailed info. I am interested in having my original alternator rewound, Today I purchased the BWD -R914 voltage regulator off E-bay . So now onto purchasing the Windy Nation 30-35A part. I’m located in Cincinnati-Ohio..

 

[Jim]

I am interested in having my original alternator rewound

Send me a PM to get the ball rolling.
Are you sure the R914 is a type "A" regulator and not a "B"? Your 81 needs the type A.

 

[5twins]

It looks like the same Fiat reg we've been using, just the BWD part number.