Testing ST1300 alternator-idea time.

Joined
Oct 6, 2007
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523
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Kenly NC
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07 ST1300A(P)
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7649
From what I've been able to discover, the main reason you can't test one of these things by regular means is that there is no way for a shop to spin it. My NTM alternator arrived with the drive shaft attached, and it got me to thinking......if I attached a pulley to this shaft, and a grub screw to lock it to the alternator, would this suffice to be able to physically spin it up on a bench tester?
What say the huddled masses......if so, I may go ahead and fashion this thing, and add it to the loaner tool list.
 
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It will work but add a load across it, like a battery first. ;)
 

paulcb

- - - Tetelestai - - - R.I.P. - 2022/05/26
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8735
Doesn't a bench tester do that?
Yes. With the pulley, an auto parts store should be able to test it. The only glitch might be the wiring harness.
 
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Ozzie
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Oct 6, 2007
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523
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Kenly NC
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07 ST1300A(P)
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7649
Just got back from the alternator place. He confirmed my theory, a pulley on the shaft will simplify testing. FWIW, mine tested 13.5 and 14.5 under load. He just ran a belt over the shaft and spun it up. He removed the main wire and attached a lead, and then attached another lead to the other harness. Guess what I'll be working on this weekend.....if work doesn't get in the way? Now, could a big box store test it? Doubtful, because they use preset harness's, and their machine is set up as a plug and play, and they won't list one for an ST1300, but a dedicated alternator shop?...no problem.
FWIW, it was the rotor coil that went bad on mine.
 
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paulcb

- - - Tetelestai - - - R.I.P. - 2022/05/26
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Thanks for the follow up Ozzie.
 
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I wouldn't take a chance with a "big-box" store checking my alternator. If it checked bad, you would never know when it went bad; before or after you carried it in for testing.
 

wjbertrand

Ventura Highway
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Just got back from the alternator place. He confirmed my theory, a pulley on the shaft will simplify testing. FWIW, mine tested 13.5 and 14.5 under load. He just ran a belt over the shaft and spun it up. He removed the main wire and attached a lead, and then attached another lead to the other harness. Guess what I'll be working on this weekend.....if work doesn't get in the way? Now, could a big box store test it? Doubtful, because they use preset harness's, and their machine is set up as a plug and play, and they won't list one for an ST1300, but a dedicated alternator shop?...no problem.
That's how they tested mine too. This was a local alternator rebuilding shop, not an Auto Zone, etc. They just looped the belt over the splined shaft tightly enough to give it a spin.
 
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Ozzie
Joined
Oct 6, 2007
Messages
523
Location
Kenly NC
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07 ST1300A(P)
STOC #
7649
Been looking at what I've got to work with. I'm going to find a sealed bearing to replace the open one, then fab a plate up to protect it, and I'll try to stop by my local bearing warehouse and find a pulley, a multi rib, because thats the most common one nowadays. I'll post pics as this progresses.
Right now I'm working on reinstalling the good alternator, That's in, but......I took pics on the I phone when I disassembled it all, and the I-Phone suffered a major failure, so I'm working from memory. At this point I'm way past confused, all those hoses in the valley..........I may put out a call for help on this one......Beer and burgers.....or sweet iced tea, apparently my wife makes good tea. I don't know, can't stand the stuff.
Still attempting to get that pesky bottom bolt in the alternator......getting it out was easy.......
 
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Ozzie
Joined
Oct 6, 2007
Messages
523
Location
Kenly NC
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07 ST1300A(P)
STOC #
7649
Went for a beer right after typing that. Sat down, drank it, went back to the ST, jammed my hand down into the valley with bolt jammed between two fingers, lo and behold, it dropped right into it's assigned place, used my swivel and extensions, alternator is now 100% in place. Now to figure out all these dangley things.......
 
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Went for a beer right after typing that. Sat down, drank it, went back to the ST, jammed my hand down into the valley with bolt jammed between two fingers, lo and behold, it dropped right into it's assigned place, used my swivel and extensions, alternator is now 100% in place. Now to figure out all these dangley things.......
So did you have to remove the radiator...? I have read in forums 2 or 3 guys who figured out how to alternator out without removing radiator by removing the back 3 bolts and plate cover off and it came out through top? Anyone ?
 
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