Battery charging problem Alternator Rotor?

I have an 81 Yamaha XJ550rh Seca I'm trying to restore and I just can't get the battery to charge. I'm only getting about 12 volts through the battery when idle at 1000rpm and I can maybe get up to 13.5 when I rev up to 4000rpms. So, the battery does charge a little bit when I just turn it on in my garage but when I ride it out in the streets and then test the battery after the ride the voltage will be less at maybe 11.5. I tested every single connection on the multimeter: stator connections, RR, brushes, ect and only one stands out as wrong-the green and brown wire connection from the alternator rotor reads at 5.6 and it should be around 4.5. So, I got new brushes and polished up the rings on the stator alternator rotor and I was able to get the ohms down to 5.3. Not quite there. I then noticed that the inner copper ring on the face of the alternator rotor was a bit receded, concave, and no longer flush with the rest of the rotor which meant that the carbon brush was unable to rest fully flush on it. And after turning on the bike it showed that the brush was in fact wearing down only on one side while the other brush showed equal sides of wear and tear. Could it be that since one brush lays fully flush on the outer copper ring and the other brush is only able to partially rest on the inner copper ring be the reason why I'm not getting a full charge? I am a newbie with motorcycles so feel free to talk to me like I'm a 5 year old.

I'm going to have my uncle who's a machinist resurface the copper rings before buying a new one but I thought I'd ask if anybody else might have come into a similar problem. i left a pic for reference. Thanks

Joshua Olkowski

 

So how old is the battery? You won't get a full charge voltage (14.5V +/- .3V) unless the condition of the battery is good and it is fully charged. Charging the battery and verifying its condition is the first step in the troubleshooting guide in the FSM for the charging system.

The slightly higher than 4.5 ohms at the connector seems to be fairly common and normally does not cause an issue. However, since you seem to be discharging when riding it certainly can't hurt to try to improve that.

What are your observations on the instrument cluster voltmeter when riding? Do you see it climb slightly when the rpm's are raised when you are out riding?

 

Rotor looks ok but what about the brushes?

 

Battery is fine. I've charged it to 12.7 volts at Autozone. I've had to do this a couple of times because we keep starting and stopping the bike to try it and the battery eventually goes below 12 volts. I replaced the brushes.

Can you tell me or show me the a link that says what the stator output should be when the bike is turned on. There is continuity at the stator connections but I want to check the output

 

Yes, I do see the voltmeter climb when riding but at idle it rests at 11 volts or so.

 

Bad batteries can hold a full charge but not deliver sufficient voltage for starting purposes due to an internal short when under load.
Put a meter to the battery posts and see what it drops to when attempting to start the motorcycle.

Also,

From: The Information Overload Hour (red emphasis mine)
Charging System Tests:

a) Adjust voltmeter to DC volts (20 volt range).

b) Place voltmeter leads to the battery terminals (positive to positive and negative to negative).

c) Start the engine.

d) Bring engine up to approximately 2,500 rpm's.

e) Compare the voltage reading to the specification given below:

For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):

* approximately 500-2000 rpms: 1.8 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)
* 3000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all XJ700-X and XJ750-X)


NOTE: the voltage reading must be approximately 14.0 - 14.5 volts to properly charge an AGM battery......anything less, and you will quickly kill these type batteries!

If your charging voltages are too low, suspect the alternator brushes first, then perform the alternator stator and rotor checks as described in the Alternator Section elsewhere in the catalog. Alternator brushes should be replaced whenever they are less than 11mm in overall length......the factory maintenance interval indicates that you should expect to replace these brushes every 8-10,000 miles. Factory brushes have "wear marks" (scribed lines) on the brush to indicate their wear limit; these aftermarket brushes also have the scribed wear line. Overall length of these brushes are 17.10mm, with 9mm of length from the wear bars to the contact end of the brushes:

 

With the stator connected and the bike running you should see about 11 VAC at idle, and around 13 VAC when revved when checking between phases - white to white.

If you want to check them with the stator disconnected:

Note that the charging system is running open loop and no load in this mode with the AC generator output disconnected - no voltage to the IC regulator so no feedback, and no battery to provide a load. That means maximum AC voltage will be outputted as the IC regulator supplies maximum current to the field coil trying to increase the output. I did not want to rev too high because of the open loop condition.

Idle of about 1100 RPM = 18.5 VAC
Rev to about 2100 RPM = 30.5 VAC

This is measuring phase to phase, and should be equal between any of the 3 wires.

If you want to check the field coil / regulator it can be done like this. A bit complicated but it gives a good indication of current being supplied to the field coil and therefore the condition of the assembly, including the brushes.

 

With my 81 Yamaha XJ550 Seca engine running at 2000 RPM and a voltmeter connceted across the battey terminals the alternator output will not go above 12Vdc.

• The voltage regulator/rectifier is brand new
• The battery is in good shape and takes and holds a full charge off of a charger.
• The alternator bushes are brand new (17mm overall length)
• The resistance between the three legs of the alternator stator are within spec
• The stator AC voltage output between all three legs are consistent
• No shorts between stator windings to ground
• No shorts between rotor windings to ground;
• The resistance across the rotor slip rings is within spec
• The rectifier diodes are all good
• Continuity is good on all the wires and connectors involved with the charging system
• The continuity from the tip of rotor brushes to the two pin connector is good
• No short to ground on any of the wiring.

Now here's the thing that got me. With the rotor cover (and brushes) on and the wiring connector for the rotor brushes disconnected I am measuring about 12 ohms across the two pins on the engine side of the connector.
However, the resistance right at the slip rings is about 4.5 ohms. Like I said; the brushes are new. Also, the slip rings are bright and shiney. Brush spring pressure is good. All terminal screws are clean and tight. Seems the brushes are not making good enough contact. Any suggestions on how to resolve this?

 

tell us all the measurements you have made.
read about the charging system in this link.
https://www.xjbikes.com/forums/threads/the-ultimate-relay-switch-sensor-and-diodes-guide.27543/

battery is battery acid battery or sealed type
"with the engine and all electrical accessories off, the battery should read a minimum of 12.8 volts DC. If not, the battery is either not fully charged, or it is bad (it is incapable of holding a full charge). Charge the battery fully and check again; if the reading is less than 12.8 volts, the battery is bad and should be replaced."

brushes
about 12 ohms across the two pins on the engine side of the connector.......However, the resistance right at the slip rings is about 4.5 ohms.

measure the resistance from wire to end of brush look for loose, corroded or dirty connections.
are the slip rings smooth or grooved?
did you replace just the brushes or the holder/brush assembly ? springs may be weak or brushes sticking in the holder.

,,,

 

Battery is fine. Holds a charge up to 13.1 volts. Brushes and springs are brand new. The slip rings are very smooth.
Thanks for helping. Any other ideas would be greatly appreciated.

 

Doesn't mean it is working

And the readings were? Was it checked open loop or closed?

And in your other threads questions were asked and never answered, which makes it difficult to respond with helpful suggestions.

 

did you ohm from connector to end of brush?? you said you had 4.5 ohms on the rings but it went up to 12 ohms when reading from wire to wire when assembled. so you are picking up 8 ohms through the connectors wires and brushes (thats called out of spec). crimps may be corroded internaly along with the wires.

also use crocus cloth and clean the grounds. start with harness ground on coils the ground is connected to mounting bolts. then clean the frame ground from engine to frame . it is the screw located on bottom right side of battery box. that wire runs back to motor and is part of the battery ground cable. next is to clean the motor ground where that wire connects. Clean and tighten battery terminals too. battery can not charge if there is no ground path the motor is isolated from frame at least not well grounded to frame through its mounting bolts

 

To add to Rooster's comments; keeping things in one thread is really helpful.
It quickly becomes difficult to give good advice when information is spread across multiple threads.
If we miss something important it wastes your time, and may cause unnecessary frustration.

 

set your idle to 1200 rpm. 1050rpm is spec.
do not trust voltmeter in cluster.

the concave copper ring is a problem , maybe the brush will wear down and make full contact with ring

 

other threads
https://www.xjbikes.com/forums/threads/battery-charging-problem-alternator-rotor.119858/

is copper ring still concave?? that would be a problem may fix itself if brush wears to shape but I wouldnt count on it.

 

I figured out the problem. Turns out, the fuse box was no good. In short, the main fuse connections were old and brittle and couldn't carry enough current thereby not giving enough power to the rotor to excitate. I didn't realize that current was needed in order to make the rotor/stator to work. I, as a newby mechanic, thought that it produced it's own current. One day, the main fuse burned a hole through the casing which indicates that there is resistance at the connection where the fuse sits. I replaced the entire fuse box and voila. Battery is now charging and the bike is fully functional...….let's not talk about the fact that I was so excited I took the bike for a canyon ride and crashed it. Good times.

 

Sorry to all if I am all over the place. I figured out the problem. Turns out, the fuse box was no good. In short, the main fuse connections were old and brittle and couldn't carry enough current thereby not giving enough power to the rotor to excitate. I didn't realize that current was needed in order to make the rotor/stator to work. I, as a newby mechanic, thought that it produced it's own current. One day, the main fuse burned a hole right through the casing which indicates that there was resistance at the connection where the fuse sits. I replaced the entire fuse box and voila. Battery is now charging and the bike is fully functional...….let's not talk about the fact that I got so excited I took the bike for a canyon ride and crashed it. All that work restoring a classic bike down the drain. Good times.

 

Well, at least you are writing about it and here is hoping you don't have any major bumps or bruises.

That is an odd one. The rotor excitation is at max only a couple of amps but with the headlight and other accessories running current through the main fuse it is quite a bit higher. It's kind of surprising it would even start if the main fuse connection was that bad.

 

At least you’re alive to talk about it

 

I agree. I just started trying things because I was at a loss. There were several issues with the bike starting I might add. Sometimes the motor would crank really strong but there was no spark and the battery would be at 13.1 volts. Other times the battery would be at 12.1 volts and start up right away. My only guess is that the fuse connection would get really hot and not conduct as well when it was cool. I will say that after installing the new fusebox (bought off this site, btw) the bike had so much more power and just ran smoother overall. And as a newbie rider these Secas are really fun bikes.

 

Very true. Very humbling experience. I just came off an 800 mile bike ride on a BMW GS1200 and I started getting a little too cocky. Thought I could do anything after riding that beast.

 

Very much also agree that I'm still alive to talk about it. Common sense went out the window. Very humbling experience.

 

Have you ever dumped your bike in front of 1500 high-school students on your way home from work?
I have.
Weeks, and weeks of reminders followed...lol.

 

Or do like I did back in my first year of riding ? Catch a bump and fall off the seat trying to bump start a Virago (must've done it in wrong order).. Then watch it drive, unmanned... wobbling to the ground back in front of the motorcycle shop that I'd just picked it up from. ...Just can't make this stuff up!

Glad you're ok! I hope you don't give up on these old bikes, though!

 

the battery charges through the main fuse. when the bike is running every thing runs off of the alternator and the battery charges back through the main fuse

 

That makes even more sense why it wasn't charging.

 

I'm a substitute teacher so I'm right there with you.

 

Thank you for responding. I am going to try what you said. I thought the fuse box worked but I'm still having a charging issue.

 

Hi and thank you for replying. The fuse box change did not fix the problem so I'm back to square 1. Maybe you can help me. Today I hooked up a brand new battery just to see what happens. Well, I can honestly say I'm getting better results but I'm still not at spec. I decided to drive around and see if anything changes I measured the new battery before I left which read 13v, took it for a ride, and when I got back I measured the battery with the bike off and it read 12.79. I then checked it at idle (1500rpm) and it just continued to drop. However, I revved the bike up to 5000rpms and the volt meter read 14.1volts which is the highest I've seen on this bike. Could you walk me through the wire to end of brush continuity check? I'm not exactly sure which wire it is. Thanks.

 

unplug the rectifier connector
at the connector you will find a dark green wire and a brown wire
set your meter to ohms lowest setting
from the connector touch probe lead to green wire then the other probe to end wire where it connects to brush , then to end of brush on the surface where it contacts copper ring of brush.
then test for the brown wire.
you should be getting zero ohms.
also test your meter by touching both probes together to see what you get for a probe to probe reading again this should be zero.

test specs
The Ultimate Relay, Switch, Sensor, and Diodes Guide
Your charging system output VOLTAGE should be checked, again at the battery terminals, while the engine is running. The measured voltage should be:

* 14.2 - 14.8 Volts at about 2,000 rpms for all non-X models, and the same voltage for "X" models, but at about 3,000 rpms. Again, you would measure these voltages at the battery terminals with your voltmeter.

test is done at 2k rpm
12.8 volts should be the standing voltage of the battery (first test before starting battery sits overnight )


is copper ring still concave?? or did your uncle fix it
I'm going to have my uncle who's a machinist resurface the copper rings before buying a new one but I thought I'd ask if anybody else might have come into a similar problem.

 

So, I actually went out and bought a new battery. After properly prepping it I hooked it up and started the bike. Unfortunately, it was somewhere around 12.68volts or so at idle (1500rpms). Not spec. However, I revved up to 4000rpms and I received 14.1 volts which is the highest reading I have gotten so far, but still not spec. I decided to ride for about 5 minutes or so but I measured the battery first and it said 13.1 volts. When I came back the battery measured at 12.78. I thought, oh well back to the drawing board. The next day I said screw it and decided to try my luck and go on another ride but I measured the battery before leaving which was somewhere around 12.8 volts. After a ride of about 30 minutes I arrived home and measured the battery again. 12.84! Not bad. I went for another ride about 3 hours later. This time only for about 15 minutes and I measured once more upon coming home. 12.98volts!!! The battery is staying charged!!!! I also noticed that the needle on the volt meter on the bike rests right on 12 volts when idle but when I ride it consistently shoots up higher to 14volts!!!!! Wasn't doing that before. I came across some information about a batteries "internal resistance" where it may be able to hold a charge when left on a charger but when on the bike it doesn't have the ability to charge as fast because of internal resistance. Nevertheless, the bike still does not idle at 13.5 nor does it ever reach 14.5 when I rev it up to 4000rpms. So, what gives? Did I just have a bad battery before? Is the new battery just performing better because it's new but will quickly die out because I'm not reaching spec? In any case, I will try your wire to brush test and get back to you. Thanks for your help.

 

You must have a functioning fully charged battery to reach the 14.5 +/- .3 volts.

It should reach the 14.5 volts at a lower rpm, but only if the battery is fully charged. Expecting 13.5 volts at idle is not going to happen with the standard setup.

Here is a link of a working system that was posted some time ago. Note the comments (post #20) about the charging voltage vs a fully charged battery:

https://www.xjbikes.com/forums/threads/battery-and-reserve-power.14177/#post-588051

 

I read the post and from what I can tell I guess I'm fine but I'm still confused. What should the battery be reading at idle? According to the manual it says 13.5. And there's absolutely no way I'm getting 14.5 at 2000rpm. At this point I should just be happy that the bike is not losing a charge. I just checked the green and brown wire at the RR harness and it says 70ohm!!!! I checked it last week and it said 5.9. I just don't understand anything anymore. So, I did the test checking the ohms from the end of the green/brown wire to the brushes and I do have resistance but not a lot. I first touched the probe to the brush holder (brand new) and it basically read about 0.5 ohms on both. Then I removed the wire from the holder and measured it again at the copper ring holder thingy and the results were the same. Then I actually touched the probe to the tip of the brush. It bounced around but eventually stabilized around 1.0ohms on each. Are these figures bad? I happen to have and extra harness that I grabbed from another bike (see picture) and the readings are basically the same. I sprayed some electric spray on both to clean it up but it didn't work. I'm wondering if the culprits are the copper ring pins that actually hold the wire. Please see picture. Should I replace these? If they do need to be replaced is there some tutorial on how to take those off without losing the wire. As you can see I tried once and in trying to preserve the wire it all just fell off. Thanks again. Josh

 

It kind of depends on what the idle speed is. You can see in the video referenced in the above link that the 750 breaks even at just above 1000 rpm with just the headlight and tail light active. Activate the brake light and it takes a few more revs. That said, a properly functioning charging system should reach the stated 14.5 +/- .3 volts at just above 2000 rpm with a fully charged battery.

You can also tell when the charging system has reached the break even point with voltage. It is not as accurate as actually doing the current test as the system is a bit dynamic and a good battery will quickly charge.

1.Turn the key on and note the battery voltage.
2. Start the bike
3. Slowly rev the engine, when the DMM voltage equals the reading in step 1 the charging system is supplying the power to run all the electrics.
4. Continue to slowly rev the engine, when the DMM exceeds the reading in step one the charging system is running the electrics and supplying charging current to the battery.

Wow, 700 ohms with the DMM gives the impression that it would not work, however you are close to getting good charging numbers so obviously that is not the "real" number while the field coil is rotating. Did you ever have the slip rings cleaned on the field coil cleaned up as asked by XJ550H?

With the resistance readings you got it would seem the wiring is OK. You can clean up the eyelet terminals with some 400 grit sandpaper and a spray and wipe with contact cleaner to remove any residue. To replace the eyelet terminal you would need to just cut the wire and get new terminals and the proper crimping tool. It's not really possible to remove the wiring from the existing terminals that have been crimped.

Do you have your own charger or battery tender? I can't stress enough that when evaluating the charging system looking for a predetermined voltage the battery needs to be fully charged.

 

And here is a video showing what the results are with a discharged battery. I did this at the time the other video was posted in the above link to the other thread by shutting the bike down and leaving the head light and tail light on for nearly 30 minutes.. Note that battery voltage at the 31 second mark is just over 12.5 volts with the bike revved to nearly 3K, but current input to the battery is over 13 amps (total of two meters). That's a charging system at nearly peak capacity - 13 amps to the battery plus approximately 5 amps to run the headlight, tail light and miscellaneous electrics.

 

Wait a second. Let me get this strait. Are you saying that I have to factor the electronics in when measuring total output? In other words, If my bike is at idle and it reads 12.5volts and then measure the electronics where I might get 1 volt then you're saying the max output of voltage would be 13.5? If this is true then I am well within spec.
To answer some of your other questions it was 70.0 ohms, not 700. Sorry, should've written that better. But I will say that everything is working superbly since I put in the new battery. I hate to say it (tail between my legs) but I've read probably 100+ posts of people saying to check the battery first when having a charging problem and I ignored them. I ignored them because the battery was able to start the bike so I figured it was fine. It now charges at idle and everything is working great. Keep in mind I really cleaned up the wires, changed the rotor, new brushes, and new fuse box but I wonder if I could've avoided a lot of misery and saved money by just putting a brand new battery in there in the first place. Live and learn.
Oh and I did manage to get a rotor off a Seca parts bike which looked better then mine and was well within spec.
At this point I'm going to let the electrical be and start focusing on other parts of the bike. Unfortunately, the previous owner welded the exhaust to the chasis. Ugh. Plus, because of the accident the handlebars are slightly bent and other various cosmetics need to be fixed.. I rode it into town and while parked some guy put a dent in my newly painted gas tank. It just never ends with this bike. But it runs and is still a head turner and for the streets of LA that's good enough for me.

 

you should not have to go through all the voodo math to get correct readings. I get the proper readings just testing the battery.

I belive rooster was showing you how your alt is putting out correct voltage but you can not see it because of the condition of the battery. he is also measuring current output of the alt.
get a 10$ battery tender keep your battery charging then test after a night of charging.

when you do change your rotor you will need new brushes,

 

Well, I am not sure I said exactly that. I was mainly trying to stress the need to have a fully charged battery when evaluating the charging system for a predetermined voltage - 14.5 +/- .3. The point is you will not get that voltage until the battery has reached near full charge. That said, you should be able to take the bike out for a somewhat extended ride (30 minutes or so) and when you return then check the charging system. The battery should be fully charged and you should get really close to the 14.5 spec. Or as XJ550H suggested, leave the battery on a tender overnight and then evaluate for charging voltage.

The other new parts did not hurt, but most likely the fuse box was the main issue. The weak battery likely exacerbated the problem causing the charging system to attempt to supply excessive current to the battery through the main fuse, which then went into thermal overload making the situation worse. The poor connection coupled with excessive currents eventually burned the box as you mentioned.

Agree live and learn. We have all been known to chase our tails a bit when restoring these older machines, but in the end the successes and learning experience can be what makes it all worthwhile.

 

$$ some times are worth the spending
new battery
new brakes
new tires If needed

 

Hi guys. I've made a new discovery with the stator that's a bit confusing so I'm hoping you can clear it up. I decided to take my bike in to a mechanic to see what he might say about the charging system. He said I needed a new stator. I could've sworn the stator was reaching all diode and charging specs. So I took it home and measured the coupler unplugged that comes directly out of the stator and sure enough it's reaching spec which is to say it idles at about 18volts (AC) and when I rev it up it goes off the charts. Now, in keeping the meter probes where they were I reconnected the stator to the coupler going to the RR, fired up the bike, and lo and behold all the numbers go DOWN instantly. It now idles at 10 or 11 volts (AC) and when I rev it up it maybe goes to 12. With the bike still idling I disconnected the stator again and sure enough all the numbers come back up to charging spec. Is this normal?

 

Yes it would be normal. With the battery (the load) connected it will limit the output voltage of the stator. Also, when connected and operating in closed loop the drive to the field coil will be reduced decreasing the stator output depending on the charge of the battery and the need to supply charging current.

Did he get specific about this and say how he came to that conclusion?

 

No he didn't but I'm wondering if he measured the stator at where the RR is rather then where it directly comes out of the stator hence the numbers.

 

In any case I just learned about load tests so I conducted one on the brushes where you connect to the positive lead on the battery and one on the positive brush. It read 11.75volts and as I understand it the difference should maybe be 1 volt. Is this correct? Is there a lot of resistance going from the battery to the field coil?

 

Not sure exactly what you are doing here, is everything connected and the key set to "ON"? With that connection and if everything is connected the DMM is measuring the voltage drop across the wiring, main fuse, and ignition switch, which should be quite low - perhaps <1 volt as you were suggesting. If the key is off you are going to measure close to battery voltage as you are measuring across an open switch.

There is virtually zero resistance between the battery and the field coil positive side. Switched voltage from the ignition switch is fed directly to the positive brush. On the other side (negative brush) the regulator will control the current through the field coil based on the value of the sensed voltage . By doing that it will control the strength of the magnetic field in the field coil and consequently control the output of the stator.

And just to add a note on the stator since this was not that specific before, you need to check the voltage between all three wires to verify voltage is present. It is possible to have just two phases working, which would result in a degraded charging system. The continuity check is the same in that you must check between all three (and to ground) to verify the integrity of the stator.

 

Thanks Rooster. Turns out I measured the wrong brush. The correct reading for the voltage drop test from the battery to the positive brush is 0.26 volts. I was reading an article about it and it says to check this if you're not getting magnetism at the alternator from turning on the keyswitch. I am not getting any magnetism when I held up a paper clip against the alternator cover. I was hoping the voltage drop test would help clear it up but the reading is pretty good. I'm still getting weak charge to the battery though.
I cleaned up the rotor surface until it was super shiny, attached it, and when I meter probed the green and brown at the RR coupler it read 5.6ohms. Not bad considering it was in the 16ohm area for a while. However, I took the bike for a spin and when I returned I measured it again and it went back up to 16. Not sure what's going on except maybe the heat is messing with the numbers a bit or the brushes are leaving a residue.
I have to admit I did not properly check all three phases of the stator but I'm pretty sure they are all good. I will check again. thanks.

 

The distance from the field coil and the weight of a paperclip is a bit too much. You can do that with a very thin feeler gauge (.002) placed very close to the cover (1/16 inch or so) and turn the key on and the feeler gauge should pull toward the cover. And since you were able to measure the stator AC output in open loop mode the field coil / regulator are working at least partially.

I was curious about the remark it is reaching spec, I don't recall any published data from Yamaha with specifications for testing the AC Generator in open loop mode. Did you find those in a service manual or somewhere else?

 

It was actually you. You're the one who told me the spec numbers for stator output. Thanks for telling me about the feeler gauge. I decided to stop buying used parts to fix the charging system. I tried a used RR and a used stator on this bike and they are both 35+ years old. I'm going to start putting down for brand new parts.

 

Oh, I see and yes I did publish some nominal voltages. I guess it's just the internet way of communicating (or not) as I was interpreting "spec" as black and white from perhaps a service manual.

So reading back through the thread it seemed the latest was you were riding and the battery was maintaining a charge, is this still true?

You also replaced the battery, what type and brand did you get?

And did you ever get a battery tender so you could properly charge the battery overnight and evaluate the system with a fully charged battery?

 

Unfortunately, the bike is not charging. It idles around 11.9 volts and when I rev it to 5000rpms it goes to about 12.40volts. It's interesting how when I put a brand new battery on the bike the numbers were way better. The battery is only about a month old. The brand is Super Start. I don't have a battery tender but I do have a charger that I have often used. My next stab at the problem is to replace the RR and Stator with brand new parts. I replaced them before but both times I bought used and these parts are 37 years old!!!! I'll try the RR first and if that doesn't work then I'll try a new RR. Here we go!