I have a 86 evo and my battary keeps dying.
I went thru many forums to troubleshoot the problem.
I even replaced the regulator thinking that was the problem, and no luck, so here is whats happening.
With the bike off I get 12.6vdc. With the bike running the best I get is 12.8vdc at 2500rpms.
It seems like the stator just cannot produce enough amps to charge the battary.
Is there anything I can do to find out why this could be happening.
The bike only has 27k miles.
I have done the meter tests while off and on, checked for good ground, checked for good wires.
I did find the old regulator had cracks in the wires and the back of the reg had holes in it where the wax is, thats one reason I swapped it for a new one.
I am just without ideas and I am trying to troubleshoot without pulling the primary off unless its the last resort.

Please help....

Thanks in advance...

Jeff

 

You should-a come here first.


Dr.Hess' How To Diagnose Your Charging System

Buy about a $10-20 digital multi meter. Fully charge the battery (overnight on a 1 Amp charger).


Scale on DC Volts, around 20V max voltage scale. Nominal readings are given in brackets. Check voltage across battery terminals (12.8). Turn bike on. Check voltage (less than previous, ~12.0+, depending on headlight, accessories). Start bike and let idle. Check voltage (could be 12.0 to 15). Rev to about 2500. Check voltage (should be more than observed with bike on but motor not running, and more than with bike off. Ideally between 13 and 15.) Turn high beam on. Should be about the same, give or take a little. If the voltage is over 15 or 15.5-ish with a headlight on, I'd consider replacing the regulator and/or checking all grounds (battery to frame, regulator to frame in particular). If the battery voltage with the headlight on, bike not running is less than around 11.5-ish, I’d replace the battery. If it’s 10, it’s past it’s prime.

If you pass the above tests, your system is most likely fine, including the regulator and stator. If you don't pass, then:

Bike off. Meter set on Ohms, medium-ish scale, like 20K or 200K Ohms max scale, depending on your meter. Pull stator plug. Ground the meter black lead to a good chassis ground, like a bolt or even the battery negative. With the red lead, touch a different part of the bike, like the engine case at an unpainted part or another bolt. Meter should read low ohms, like 0. If it doesn’t, you didn’t ground the black lead. With the red lead, touch each contact on the motor side (stator) of the plug (the part stuck in the case). Depending on if your case has a male or female plug, if you can't see the metal part/pin of the plug, you can put a paper clip in the hole and touch the paperclip with your meter red. Meter reading should be infinity on all pins. If it isn't, your stator is shorted to the case, replace.

The following is for single phase systems. I don't have a multi-phase and haven't had to diagnose anyone elses, so I haven't dug into those systems.

Set meter to lowest ohm scale, like 200 Ohms, typically. (Note: Not 200K ohms). Check resistance between the two stator plug pins. Should be fairly low. My Book says 0.2-0.4 ohms. The spec is in your shop manual. If it is infinity, stator is blown open. If it is 0, stator is shorted to itself.


Set meter to AC Volts, 100V scale. Attach each meter lead to a stator pin. You may need to rig up some type of temporary plug. It is important that nothing can short to ground or to each other accidentally, or you will blow the stator if it wasn't blown before. An old plug off of your last regulator is a good way to do it, but, get creative and be careful. I can do it holidng the leads on the pins once the bike is running, but I don't like to. Start bike. Voltage should vary with engine speed. Specs are in your shop manual, but 35V at a couple thousand RPM is probably about right. My book says 19-26 V / 1K RPM.

If you passed that stator test and failed the first test, your regulator is shot. If you failed any part of the stator test, replace both regulator and stator.

 

Dr. Hess' excellent instructions pinpointed Bertha's problem recently - the regulator.

You also need to check your rotor, to make sure all of the magnets are still firmly attached and haven't come loose and shifted around. There was another thread here in the last week where the rotor turned out to be the problem with weak stator output. His rotor magnets had come loose and shifted, and this messed up the magnetic fields that are designed to be generated by the action of the rotor rotating around the stator. He was only getting 12 VAC from the stator, but after he replaced the rotor with a new one, he got about 60+ VAC.

You will have to pull the primary cover, and the primary drive (compensator sprocket, primary chain, and clutch) to get to the rotor... sorry! BE CAREFUL with the rotor if you have to install a new one!!! Those magnets will grab hard onto the stator when you put it on, and you can pinch a finger easily if you have it in the wrong place! Handle the new rotor ONLY on the FRONT outside corners to avoid getting a finger caught when it grabs onto the stator!

 

A tried and true method to see if the stator is fried is to remove the derby cover and smell. If it's fried you will get a burnt smell that you will never forget. Checking as per the good Dr. is the definete way.

 

Yjanks for the replies, I have done all tests that can be done without pulling off the primary cover. I guess the next step is to get the cover off to inspect. I have heard that behind the cover is a lot of parts that require experience to handle plus special tools. Is there a DIY somewhere that will explain how to dissmantle properly and what tools will be needed. I have my repair maual but it seems to vague for someone who has never done this before. What should I expect for any concerns for alignment if I decide to tear this apart.
I just may take it to a shop for them to deal with if this gets to messy. Also if I have to replace the rotor or stator, what is a good vender to buy from for an 86 sportster evo, and does anyone have a ball park on what one of these would cost.

Thanks,

Jeff

 

You may find the following thread informative, even if it is not for the same bike. He does show his home made primary locking tool which is a must to take off the compensating sprocket. He has several good pictures. Make sure you follow the directions in the manual for your bike, because the rotor and clutch etc. removal procedure on your bike may be different, but looking at his pictures may still be very helpful.

https://www.hdforums.com/forum/touri...need-help.html

let us know what your find.


joe

 

Well I took a lookk at the reference directions, wow that seems like a lot of work and a lot of time, Thanks for the pointer on the primary chain tool.
I will need to do some studying on my repair manual to see how difficult this may be, Doesnt look like there is anyway to take a peak without a whole teardown.
I am not sure this is a job for me, I hate to get part way into this and get stuck and have to take it to the shop for them to fix my messup then when something goes wrong the shop will blame me since I messed with it prior to bringing it in, this might have to be a winter job.
Until then I must keep plugging away with the charger.
Jeff

 

Is this a 86 Sportster or Big Twin? When we say "Evo" we usually refer to Big Twin Evo motors, referring to Sportsters as Evo Sportsters.

Regardless, the directions I gave will pinpoint your problem. If you followed them (correctly), you will know what your problem is. If you didn't follow them, well, then, I can't help you. Note though that if you're bike is a Sportster, it may be difficult to check the stator output. You should keep the plug off the old regulator and use that for testing.

I kinda get the feeling this is all over your head. Pulling a Sportster clutch is no easy job. I've done it on an 87, which should be identical to yours, and yes, you need some special tools and it is a PITA. The stator is behind the clutch basket. I think it's time for some professional assistance.

 

Yes I have a 86 sportster 1100 evolution, first year.
I have done some more reading and I ran across something that I need another opinion on.
I mentioned I installed a new regulator, well I never really tested either the old one or the new one since the old one was cracked up and I took it for granit that the new one was good, well I read that when the bike is off do a meter test on the regulator by doing the following,
Take the black lead from the meter to a good ground, take the possitive lead from the meter to each side of the 2 pin connector from the regulator and one at at time thou, and set your voltage to dc and start going down to 0 dc on the meter, if you get any type of reading the diode is bad, and the regulator is is bad.
Well I did that and both sides I get about 7vdc from each pin.
Should this be happening, could this regulator be bad?
Is this instruction a good one to test the regulator?

Thanks,

Jeff...
P.S. I am not giving up until I have to go into the basket, then its over for me, I will take it to a shop to deal with, not worth it if I screw something up and it ends up costing me even more money if I do something wrong..
Thanks again for all your help here

 

May be over some heads, but not this one. Thats one of the most comprehensive charging system diagnostic breakdowns I've ever seen. A real keeper and It'll live forever in my shop notes.

Thanks Dr. Hess and thanks to everyone who's contributed.

Craneman1