I went out to start my bike on this wonderful warm day and found the battery totally dead. No lights, nothing. I put my battery tender on it and it is charging. I had this same problem at the end of last year and installed a new battery. Obviously, something's not right. Where do I begin?

 

Id charge the battery back up,then get the bike started
And check to see if the charging sys. Is working with a volt meter.
With lead on each batt. Post it should show an increase
In the volts when you blip the throttle.

 

Dr Hess will be along soon! He published a guide a while ago to checking charging, but it's buried in another thread. Hopefully he can point you to it.

 

https://www.hdforums.com/forum/evo-c...ok-a-poop.html

 

This what your talking about Graham? I keep it on my iphone.
TO CHECK CHARGING SYSTEM
The first thing to check if you suspect a charging problem is the battery and the wires attached to it. If the wires are loose, make sure to tighten them up. If you see any corrosion, disconnect them and clean them off with a wire brush before re-attaching. Check each cell on the motorcycle battery to make sure the electrolyte is covering the plates, if not, carefully add distilled water until the fluid reaches the "top" line on the side of the battery. If your battery is less than fully charged, use a low amperage charger (1 to 3 amps) and charge it until the indicator says it's full. If it doesn't take a full charge, replace it with a new one.
When your wires are clean and secure and the battery fully charged, you can get started checking the system. Perform the following checks:
Battery: Turn ohmeter 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 multimeter 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 alot higher when you rev the engine, you could be overcharging due to a voltage reg 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 multimeter 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 multimeter 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 multimeter 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 doesn't increase when the motorcycle is running, the regulator isn't doing it's 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.
Second way to test:

Step 1. First and foremost load test the battery. Even if it measures over 12.5 vdc it can still be bad under a load. Battery is typically rated at 19 amp hours and 270 Cold Cranking Amps (CCA).

Start the engine and measure DC Volts across the battery terminals, the regulator should be putting out 14.3 - 14.7 vdc at 3600 rpm and 75 degrees F.


Step 2. To check the regulator unplug it from the stator. Take a test light and clip it to the negative terminal of the battery and then touch first one pin and then the other on the plug that goes to the regulator. If you get even the slightest amount of light from the test light the regulator is toast.

To do this with a meter: black lead to battery ground, red lead to each pin on the plug, start with the voltage scale higher than 12vdc and move voltage scale down in steps for each pin. Any voltage is a bad regulator.


Step 3. On the other part of the disconnected regulator plug. Set the multimeter for Ohms x1 scale and measure for resistance across the pins of the stator. You should read something around 0.1 to 0.2 ohms for the TC88 32 amp system.


Step 4. Then check for continuity between each pin on the plug and frame/engine ground. The meter needle should not move (infinite resistance)(digitals will show infinite resistance) if the meter needle does move (indicating continuity)(digitals will show some resistance), recheck very carefully. If the meter still shows continuity to ground the stator is shorted (bad).


Step 5. Set the meter to read A/C volts higher than 30 volts (the scale setting for voltage should always be higher than the highest voltage you expect or you may fry the meter). Start the bike, and measure from one pin to the other on the plug (DO NOT cross the multimeter probes! - touch them to each other). You should read roughly 16-20 vac per 1,000 rpm.


Step 6. If the battery was good under load test, if the stator is NOT shorted to ground, and the stator is putting out A/C voltage, then the regulator is bad (most likely even if if passed step 2).


Generally the following is true:
22 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.2 to 0.4 ohms.
32 amp system produces about 16-20 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.
45 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.

 

Hmm thought the fist post was Dr Hess's test , probably was.
But here's his for sure
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 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. 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. 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, typicaly. Check resistance between the two stator plug pins. Should be fairly low, like a few 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.
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.
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Thank you. I really appreciate the effort some of you have gone to to provide answers. I'm a real novice when it comes to working on my bike, but I know it's possible. Thanks again.

 

You guys are fast.

 

Ya I got it stickied.

 

Yeah, I must apologise for Lynn, he really went over the top!