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Old 05-16-2009, 10:19 AM   #1 (permalink)
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Help

Ok guys..im new to the forum and also new to HD. I recently purchased my first HD. I bought a 79 Sporty. Since then i have had problems go figure. I put a new S and S super E Shorty, New Voltage Regulator, Battery Plugs. Whats happening is that I fully charge the battery roughly 13V. I polorized the generator. WHen running the bike, i hooked my dmm to the armature post and tested between 9.5 to 10.5v at idle and roughly 13 to 14v at 2000rpm(apporx). Now I hook the dmm to the battery and see little if no flucuation. I backprobed the 3 prong connector after the voltage regulator and still nothing where it should be. I just put the regulator on yesterday. Im just lost now. Its also got a new 15amp circuit breaker, i checked my grounds which are good. Im not sure if the start relay under the bike would be of any concern? Also for example . I rode last night lights getting dim etc. Bike dies. I pull over and my buddy comes and jumps it. Fires up ride all the way home no issue. Shut it off and try to start it again Click. thats the second time its happened.
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Old 05-19-2009, 05:28 PM   #2 (permalink)
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i'd say have your generator checked out. the bike should run off power from the generator, not the battery, which it appears it's doing.
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Old 05-19-2009, 07:22 PM   #3 (permalink)
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yah i did all the tests today.. generator puts out a 2 to 2.5 v on maximum output test vs the 25 to 30 v it should.
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Old 05-20-2009, 08:58 AM   #4 (permalink)
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Are you saying the output voltage should be 25 to 30 Volts? That doesn't sound right. On the high side it should only be 14 to 14.5.
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Old 05-20-2009, 09:14 AM   #5 (permalink)
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Originally Posted by Jbo24 View Post
Are you saying the output voltage should be 25 to 30 Volts? That doesn't sound right. On the high side it should only be 14 to 14.5.
That's at the regulator.....at a high RMP.

Not off the stator...

The voltage reg bleeds off the unused voltage, hence the heat. The newer systems are different....they put out almost 20V per 1000 rpms, before the regulator on a 32amp system.

From another site:



CHARGING SYSTEM TESTING

Battery: Turn ohmmeter to the DC Volts setting that can read 12V or more. With your motorcycle off, read from Positive to Negative making sure the Red is +, Black is -- If battery is good you should get about 12.5 to 13.5 volts

Charging: Using same multi-meter range, start the motorcycle and run RPM's up to above idle. Voltage should increase to several volts above initial reading, usually to about 14.7 V. Voltage should not go much higher than 14.7 V. If voltage goes a lot higher when you rev the engine, you could be overcharging due to a voltage regulator problem. If voltage doesn't change, your motorcycle is not charging.

Stator: If your motorcycle is not charging, you need to check the stator. Locate the plug for the stator on the front of the engine block. Switch the multi-meter to OHMS range on the lowest setting, usually 10 ohms. With the motorcycle off, read between the 2 pins or holes in the block. These should show continuity. If your meter is accurate you could read 1 to 3 ohms, but cheaper meters will not be that accurate. As long there is continuity it passes this test.

Now change the setting on the multi-meter to the highest OHM range like 100K. Touch one probe to a pin or hole in the engine, the other to the engine case or a metal bolt on the engine. The meter should not move. Try the other pin the same way and it also shouldn't move. If you get any reading the stator is shorted and must be replaced. This requires special tools and you should consider taking it to a shop. If you get no movement on the meter, it's not shorted out so you need to check for output.

To check for output, change multi-meter to AC Volts setting over 100 Volts. With the alternator plug disconnected, start the bike. Use the probes (not polarity sensitive) to read between the pins or holes in the engine block. You should read about 20V per 1000 rpm's. At idle expect about 25V, as you rev the engine it will increase to 60 or 70 Volts. If it does your stator is OK, if you get no output the stator is bad and you will need to replace it or take it to a shop.


Voltage Regulator: If your stator is not shorted to ground and has the proper output, your regulator is most likely the culprit. If your stator checks out OK but battery voltage don’t increase when the motorcycle is running, the regulator isn't doing its job and needs to be replaced. It's an easy swap; just make sure you bring the old one with you to make sure they give you the correct unit. If the battery voltage goes too high when you rev the motorcycle the regulator isn't limiting the voltage and again it needs replacement.
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Old 05-20-2009, 09:23 AM   #6 (permalink)
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You're getting the proper output from your generator. With generator disconnected at 2000 rpm it should be 12-14v, idle should be 2 to 4v. It sounds like you have a bad voltage regulator. I know you just bought the regulator but there is no set life expectancy to them. You could have gotten a bad one. Have you tested the power side of the regulator? If you have 12v on the power side of the regulator then your problem is between the regulator and the battery. Check the schematic and look for open circuits or other problems. Good luck.
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Old 05-20-2009, 09:33 AM   #7 (permalink)
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Quote:
Originally Posted by 48emodelpanhead View Post
You're getting the proper output from your generator. With generator disconnected at 2000 rpm it should be 12-14v, idle should be 2 to 4v. It sounds like you have a bad voltage regulator. I know you just bought the regulator but there is no set life expectancy to them. You could have gotten a bad one. Have you tested the power side of the regulator? If you have 12v on the power side of the regulator then your problem is between the regulator and the battery. Check the schematic and look for open circuits or other problems. Good luck.
In a generator, I agree..... I posted up for an alternator/stator.

I said the same thing, in one of his other posts. There's 2 posts going on about this, which is getting confusing.

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Originally Posted by Dave63 View Post
It sounds like a faulty regulator. It works, but fails.... When it fails, the battery is the only power, until it's dead.

The regulator resets, and after jumping it, you're on your way.

Regulators, unless transistor, are mechanical and have point contacts in them, and can fail or mechaincally take a crap on you.

His response....:

Quote:
Originally Posted by 79SportyCustom View Post
hey i figured it out it actually is the generator. Sometimes it works sometimes it doesnt.. I did a maximum output test and instead of 25 to 30v its putting out a wapping 2.5v . So i found a new one at a local repair shop for 185. or i can buy a new armature and brushes for roughly 150..
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Old 05-20-2009, 11:00 AM   #8 (permalink)
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"79" Sporty - Bad Luck year. Wierd position for the rear master cylinder making getting drag pipes for it hard. everybody i know thats owned one and theres been quite a few had a host of problems. I say sell it and move on.... call me superstitous because I'm not trying to be a jerk but i have had the "79" Sporster conversation many times for many years....

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Old 05-20-2009, 11:03 AM   #9 (permalink)
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Quote:
Originally Posted by Dave63
In a generator, I agree..... I posted up for an alternator/stator.

I said the same thing, in one of his other posts. There's 2 posts going on about this, which is getting confusing.
We must have been working on it at the same time, you beat me to the draw. Good post more detailed than mine. Electricity gets confusing on it's own with out any help.

Good to see he's got it solved.
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Old 05-20-2009, 04:06 PM   #10 (permalink)
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I tested it according to the harley manual. When you full field the generator(jumper from negative to ground) with the armature and field wires d/c it is supposed to read 25-30v at 2000 rpm. The manual also states that at idle you should read 2-2.5 v with it being d/c from the bikes wiring. When i tested the generator at idle i put out .5v and barely 1.0v at 2000rpm. It to my knowledge is the original generator from 79 and hasnt been rebuilt. So im going to put a new one on for 180 and call it a day. I wouldnt dream of selling it yet i paid 2500 for it and its overall mint. New s and s carb new battery
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