I have a 1987 FLHTC that the charging system just up and quit the other day.

It has a higher output alternator/stator (34 amp I'm thinking it is) I replaced the voltage regulator with a new one and it is still not charging.

I have checked the AC voltage at the stator plug and I am seeing 35 volts @ 2,000 RPM

Battery is fully charged and the voltage reading I see at the terminal with the lights on is 12.01 volts, where my other Harley (1988 FLHS) is 12.8 - 13.3 volts with the same amount of lights turned on.

Is it possible that the stator could be internally shorted? YET still producing the 35 AC volts, but not charging as it should?

I am lost

John

 

What is the voltage across the battery with the bike running?

 

With engine running at 2000 plus RPM the voltage is 12.01 with the headlights and running lights turned on. The voltage keeps dropping the longer they are left on, givng more of an indication it's not charging.

 

jniekamp, i just went through what you are going through. My 96' Heritage had the same problem. There are three checks for the stator. 1) voltage output, should be somewhere in the 15-18 volts ac for every 1000rpms (mine checked out at around 40vac with rpm around 2000-2500, which is what my manual called for) 2) is the continuity test. with meter on lowest ohms setting should read about 0.1 - 0.4 ohms between the pins of the plug from the stator, ( mine read 0.2ohms which is what the manual called for) 3) is the windings to ground test, with the meter on high ohms setting, one test lead goes in either pin on the plug that is sticking out of the motor that the voltage regulator plugs into, the other lead should be on any good ground of the frame or motor. there should be no continuity from either pin, (mine had short to ground on both pins, which is a fail). Even though i passed the first two tests, the third was a bad reading, and if any of the three test are bad, the stator is bad. I just replaced my stator and the charging system is back to working as advertised. I have attached a link that will explain exactly how to test your charging system, stator, voltage regulator, battery, etc. Hope this helps.
http://community.jpcycles.com/articl...g-systems.aspx

 

I will check this out tomorrow, I'm not really looking forward replacing the stator. Just had the inner primary off a few weeks ago replacing the seals in it. I guess I should have went ahead and replaced the stator when I had it apart.....well atleast I have built the tools to pull the clutch basket off and so forth.

Thanks for the input I will read over the JP cycles article over a couple of times before I make the decision.

John

 

I got lucky when i did my stator, the chain had enough slack so when i got the nut off the comp. sprocket it cleared so i didn't have to pull the clutch hub. Bad news is i am at the max ajustment for the chain, so will need a new primary chain next time it needs to be adjusted.

 

Sure it's the chain and not the nylon shoe worn? On my 88 FLHS I have only had to adjust it one notche in 24 years and 47,000 miles. The 87 FLHTC with 76,000 miles I just had to replace the shoe.

Then stop to think of it, I had to replace the belt for the first time on my 88 a couple months ago and the chain was to tight that I still had to remove the comp sproket and clutch hub. So I bet your right if you was able to get the cahin off without having to take the comp sprocket off your chain is most likely getting loose at that.

Still all in all, it's amazing how long they last, I guess running in oil helps tremendously.

 

Well unfortunately on his year bike the primary needs to be pulled off completely dew to the stater cover magnet will not fit through the inner primary.

 

You should be reading around 14 v dc

Testing Harley Davidson Charging Systems

Important information about Harley Davidson full wave charging systems (covering 70-05 Touring, 84-07 XL, 84-00 Softail, 91-03 Dynas, All FXR’s)
1. Battery Test:
The battery needs to be a fully charged battery that has been load tested to ensure proper readings. If you are not working with a fully charged and functional battery, all other voltage tests will be incorrect. Most places like Auto Zone, Advance Auto, and Pep Boys will charge and test motorcycle batteries for free. Standing battery Voltage should be 12.5-13.2 DCV.
2. Charging System Voltage Test:
Start motorcycle, Measure DC Volts across the battery terminals (you should have a reading of approximately 13.2-15 DC Volts).
3. Check Connections/Wires:
Inspect the regulator/stator plug, and check the battery terminals for connection/corrosion. If everything seems to be in order, move on to number 4 below to determine if there’s a failed component.
4. Stator Checks/Rotor Check:
Each of the following tests isolate the stator & Rotor, If AC Output test Fails and Resistance Check, and Stator IB Test Pass then Rotor is at fault (Pull Primary covers and inspect rotor for damage).


AC Output Check:
1. Unplug the regulator plug from the stator
2. Start motorcycle and change Voltmeter to AC volts.
3. Probe both stator wires with your meter leads.
4. The motorcycle should be putting out approximately 18-20 ACV per 1,000 rpm. (Reading will vary depending on system, check service manual specification)
5. Generic Specs:
· 22 amp system produces about 19-26 VAC per 1,000 rpm
· 32 amp system produces about 16-20 VAC per 1,000 rpm
· 45 amp system produces about 19-26 VAC per 1,000 rpm
Stator Resistance Check:
1. Switch your multi meter to Ohm x 1 scale.
2. Probe each stator wires with meter leads and check resistance on meter.
3. Resistance should be in the range of 0.1-0.5 Ohms. (Reading will vary depending on system, check service manual for specification)
4. Generic Specs:
· 22 amp system produces about 0.2 to 0.4 ohms
· 32 amp system produces about 0.1 to 0.2 ohms
· 45 amp system produces about 0.1 to 0.2 ohms

 

Just a follow up, my stator was fried, been up graded twenty years ago from a 22 amp up to a 34 amp and I guess after 76,000 miles it decided to crap out.

I bought a new one from Mid-USA for 50 bucks and had it installed and it's working perfect once again.

The mechanic said that he's seen all kinds of charging system failures this year for some reason, more so from any other year all the way from old bikes like mine and even newer ones.

His only thought was the high extreame heat this season causing premature stator and regulator failure. However, mine was probably due to age and miles.

Whatever the reason is, it's fix!

Thanks for the help and advice and link to the check proceedure!