Running Voltage Too Low, Now Too High

Hi All,

I was wondering if anyone has run into this issue before and could give me some direction.

About a week or so I tested my voltage at the battery terminals of my '82 650 Maxim, and saw that at 2,500 rpm I was only seeing 12.65V, which explained why my battery was draining on rides. Battery is less than a month old, AGM, kept on a battery tender, and does not seem to be bad.

This week I:
- cleaned up the copper ring on my alternator
- removed my stator. Inspected it for any issues with the wiring, and tested the 3 white legs. Between each read between .7 and .8 ohms.

Today I put the battery back in and this time when I tested the voltage at the battery, it was all the way up to 17.69V at 2,500 rpm. I quickly shut it down and pulled the battery again.

When I was experiencing low voltage I thought alternator, now with my current readings, it seems to be the R/R. The fact that I've seen both in the span of 2 weeks makes me think I could be missing something glaring and it is potentially neither.

 

Clean all the connections too. They are not sealed and poor corroded connections can cause under/over voltage situations easily. I've owned/worked on probably 100 bikes in my life and have only ever had an RR bad once, they're pretty reliable and tough components unless shorted or subjected to reverse polarity.

 

Thanks Jayrodoh, looks like I've got some more tests to run.

Concerning that the stator coil resistance should be .46 when I'm seeing .7 to .8 (it is 40 degrees here rather than 68 for what that's worth).

 

28 degrees is not going to make a huge difference in your readings. Assuming your meter is accurate, yes that is not a good reading and could indicate a short somewhere in the stator winding.

 

Test for a voltage difference between your brown wire and red wire (and throughout the harness, so at the RR, in the fuse box, at the battery etc).

Note that the voltage that the RR regulates comes from the Brown wire, and it duty cycles the voltage on the green wire to energize the rotor brushes. This duty cycling regulates the voltage output on the red wire.

Note that the RR does not regulate off of the red wire (to battery), it regulates off of the Brown wire (switched power). If there is a significant drop in voltage in switched power, you're RR would detect a low voltage and keep feeding power to the rotor, over charging the battery. The voltage between the brown and read wires should be very close (within 1V or less).

 

I fired up the bike and it looks like the voltage between the red and brown are very close (red and black = 12.65 brown and black = 12.86) at idle.

At idle the voltage at the battery sits in the high 12's and low 13's. If I give it just a touch of throttle (~1,600 rpm) it reads in the 14V range but quickly jumps into the 15-16 range at any higher rpm.

Attached is my view of the connector

 

rule of thumb. low voltage is an indicator of brushes. you cleaned the rptor rings and noh have high voltage that indicated voltage regulator.

read about charging system in this thread and things to check and clean

The Ultimate Relay, Switch, Sensor, and Diodes Guide

 

Yep I had low voltage before cleaning and now, after cleaning, have high making the brushes seem an unlikely culprit. It's the fact that I've experienced both that makes me question the indication that it would be an issue with the R/R. From what I've read they are pretty much bullet proof, so I've been trying to find any possible issues with the wiring itself.

The connections don't seem to be the cleanest things ever, attached is a picture prior to hitting them with a brush, but don't look to be non-functionally corroded. After taking a brush to connections and making sure nothing had come loose I'm still seeing the same unchecked voltage ramp up. I need to pick up some di-electric grease to hit these points before I'll rule them out.

 

The voltage regulator clamps the voltage and keeps it from going higher than it should. I've had voltage regulators past the diode test using a meter it's still allowed to higher the voltage. Change the regulator voltage back where it belongs.

 

Interesting. I wasn't aware that I could change the regulator voltage.

 

The voltage regulator is that finned aluminum box that goes on the other end of that connector. It is replaceable. the only parts on the bike that aren't replaceable directly other ones manufacturer no longer makes.

 

Go to the website Yamaha parts Nation look up your bike it look up your parts you will see schematics drawings. Voltage regulator would be under electrical 1 or electrical 2. The schematics are great for giving you an idea or insight interparts of the bikes and how they're assembled. I use partzilla myself because you would click on the part number and see what parts cross reference to other bikes

 

The importance of a repair manual. If you look at the pictures posted by, jayrodoh lower left graft chart shows voltage output of the voltage regulator and tells you right underneath it if the voltage levels on proper replace the regulator. Not trying to give you a hard time or anyting just pointing out the importance of Emmanuel

 

I think I'm misunderstanding you. I thought you meant that I could somehow change the voltage at the regulator, which I didn't think could be done. Yeah, I could try swapping out a new regulator and see if that's the fix. It's just odd because from what I've read on here those things are usually the last thing to have problems.

 

They are usually the last thing to fail. Again, if you've tested your harness, and get the same high voltage in the connector between your Red wire to the RR connector and ground, and your Brown wire in the RR connector to ground, then yeah, the RR is definitely suspect. Unless (and this is a bit unlikely), your green wire is somehow getting voltage from somewhere else, like a short. I'm not exactly sure how to test that, except de-pinning it and making sure it doesn't have voltage when it's not connected and the engine is running (you should get zero charging in that situation). But that's just pulling a test out of you-know-where

The RR are super easy to swap out. If there's anyone in Colorado nearby, or has a spare, maybe you can confirm. I've got a couple of spares but I'm in VA.

 

Gotcha. Well I just picked a used one up on eBay for next to nothing so I'll give that a test as well. If it's not the culprit I'll add it to the bonus parts collection. Thanks!

 

This is a good thought but it would be more likely the green wire was shorted to ground. With 12V on the brown wire the regulator pulls the green wire low to sink current through the field coil (rotor), this is the V2 test noted above in the service manual. As the RPM increases the AC Generator output increases so the V2 voltage is adjusted upwards by the regulator to reduce the current through the field coil to maintain the correct voltage output.

With an overcharging condition and checking the V2 voltage if it is at zero with the bike not running or does not rise with the bike running and an increase in RPM then either the voltage regulator is pulling it low or the green wire is shorted to ground, perhaps between the AC generator cover and case.

 

Update: The R/R unit I picked up off eBay came in today and I'm cautiously optimistic; I'm not seeing the spike in voltage that I was experiencing and seem to stay within the 14V range. I do want to verify with a better multi-meter before I put the issue to bed though as I don't think I should trust mine (AstroAI AM33D) and the readings seem slightly higher than they should be.

 

Troublesome Update: Took the bike out for a spin but thought I noticed something funny on the gauges, pulled into a covered parking garage to see in the shade and confirmed that my High Beam light flickers on.

Not sure if there is any particular action causing it to flicker: revving, braking, etc.

Could be from when I swapped out the gauge cluster housing a couple weeks ago, could be from when disconnecting/dropping in the new R/R unit, or maybe it could be that I'm still getting too many volts off the battery?

Will take the meter to the bike again and see if I have any wonky connections in the headlight bucket and back end.

Anyone else ever experience this?

 

test output voltage above 2krpm try at 3k rpm

 

Got out to the garage today and fired up the bike, with the meter on the battery I watched as the voltage slowly crept up towards 15 and saw the high beam lights flicker on. Seems that while much lower than with the previous R/R unit, I am still exceeding standard voltage.

This time I did not notice a particular increase above 2k rpm or 3k, even ran it up to 4k.

Rooster and ManBot mentioned earlier that I could have my green shorting to ground, I think that will be my next test.

 

Regulated voltage spec is 14.2-14.8V above 2500 rpm. So if you didn't go over 15V, and there was no increase at higher revs I think you're all set.

 

Unfortunately it does creep into the low 15's voltage-wise. It seems like revving actually brings the voltage down rather than up, likewise when I give the brakes a squeeze. Once in the low 15V range, the high beam light flickers on an off and can remain on for some time.

Cleaned and greased connections today but couldn't follow the green wire coming from the connection (that connects to the R/R unit) as it was tucked behind my battery case. Will need to remove to inspect, clean, and grease.

 

Borrow a friend's multi meter and see if you get the same results. Your meter may be off.

 

Agreed, I believe my meter is more or less giving me ballpark figures and will test with a better meter as soon as I can.

Searching the site I haven't found anyone mentioning their high beams coming on, charging system problem or not, so I am also curious if I'm barking up the wrong tree on this one and really just need to take a look in my headlamp basket. I mean I should definitely verify my voltages, but I may be looking at two unrelated issues.

 

does high beam come on and low beam go off?
or are both on at same time?

 

Good question, unfortunately with the recent cold snap here in CO I don't think I'll be able to fire up the bike for a couple days to verify. From behind the handlebars it looked the same as if I had switched over to my high beams, but I didn't get in front of it to see if both were running at the same time.

Do you think one situation would indicate something different than the other?

 

The hot wire from the headlight relay runs up to the switch in the control and when you turn from low to high the light momentarily goes out then the high beam comes on the low beamm is extinguished with the switch action. Both the high-beam and low-beam share the same ground.

 

I'm thinking maybe I need to check that relay or maybe try to clean up the switch. Today I fired up the bike and saw the same flickering action, tried to take a video:

It seems like when I give it some throttle it's fine, but as it backs down the RPMs the high beam flickers on, and sometimes seems to stay on. Tried the same action with the high beam switched on and noticed nothing out of the ordinary.

 

Have you checked your headlight switch?

 

Where in Colorado? I'm in Colorado Springs. Got a couple of good meters.

 

I have not but that's a good idea, I'll try cleaning the contacts and hitting it with some di-grease

Thanks for the offer! I'm in downtown Denver so not terribly close, maybe too far to cruise on the bike before I'm sure what the issue is. What I really need to do is get a better meter and retire this cheap one, can a good one be had for under $100?

 

Sure. Amazon has some pretty decent cheap ones. I have this one, which I bought to just keep in a saddlebag on long trips, but it compares just fine to my Fluke 287 for DC accuracy. https://www.amazon.com/gp/product/B079LY2LPF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

Thanks for the recommendation, I'll pick this one up and see where my voltages are at with more confidence.

 

Took a look at my headlight switch today. It didn't appear damaged or corroded. I did hit the 3 wires with di-grease where they make contact, though it did not seem to affect the issue.

Is there somewhere else in the switch I should be checking?

 

the switch comes out of the housing check contacts for shorts or arcs. you could test the 3 wires for continuity or ohms to each other.

one wire brings power to switch the other 2 bring the power out to light high and low beam.

it is a make break make switch. when low beam is on and you switch to high the power goes out to low before connecting to high.
when you switch from high the low goes out during switch travel then the high comes on leaving low off.

do you have a link to your light?

I think your high and low are ending up grounding through the indicator bulb if both come on at same time

could be the main ground is poor /dirty.

 

pull your high indicator bulb see if issue goes away

 

Thanks for the insight and advice! I'll pull the switch out of the housing for closer inspection and check the 3 wires for continuity.

Apologies, I'm not very technically literate.

When you say link to my light, are you asking what bulb I'm using for the headlight?
When you recommend pulling the high indicator bulb, do you mean the small bulb in the gauge cluster indicating the high beam is on?

 

are you using a standard H4 or sealed beam head light bulb or an led setup?

yes pull the high beam indicator bulb.

if you look at the wiring diagram you see a green (low beam) and yellow (high beam) wire going to bulb then the bulb goes to ground.

you also see a yellow wire running from high be
am input side of bulb to high beam indicator.

I think you may have a bad ground wire for the head light bulb, and the voltage is feeding back through the highbeam filiment through the indicator bulb making ground connection and lighting the highbeam up causing flickering .
it could be you have wrong indicator bulb but i do not think so . is indicator an le bulb?
it could be the main ground for the headlight is bad, corroded, loose or contacts in connectors bad corroded or loose. this would cause higher resistance than the indicator bulb has and force the flow of voltage through the indicator bulb, which would make highbeam come on and flicker

this is the only way I can see the flicker of high beam happening unless there is a problem with the high low switch

 

Thanks for the breakdown! I will check the ground wire for the headlight bulb as well as try pulling the indicator bulb. I replaced my gauge housing a short while back and could have potentially muddled something up in the process there. Still need to pull the switch out of the housing and inspect, but this seems like a likely culprit.

As far as bulbs go, I don't have any LEDs, just standard.

 

do you have the headlight pigtail extention? part 23 in this drawing I do not think the main harness connector actualy fits properly to headlight.
I think the pigtail was made to be scaraficial so the main harness was/is not dammaged due to heat.
https://www.partzilla.com/catalog/yamaha/motorcycle/1982/xj650j/headlight

 

Pulled the headlight switch apart, everything appeared in working order but took a couple quick pictures.

The headlight is https://www.amazon.com/Wagner-Lighting-H6024-BriteLite-Sealed/dp/B000C90MNE

I do believe I have the noted pig-tail extension, it seems to run from the bulb to under my gas tank so I believe I will have to pull it to check the far end. Odd side I've noticed is that the highbeam flicker seems to happen exclusively when at the ~1,600RPM range. Above and below it doesn't occur.

Planning to pull indicator bulb and seeing if it fixes.

 

EDit i went and pulled a headlight or 2 and the connector you have does look like a pigtail should be 4 inches long and have a white connector to connect to main harness.


switch contacts look good any wire strands on other side poking out where they should not be?

if you take off the pigtail and look into it you will see a tab push tab with a tiny sscrew driver or large sewing needle and you should be able to remove metal contact for ground on both ends clean them inspect connector bodies to see if the show signs of melting. also check the main harness connector for melting.
clean contacts a little dielectric grease and reassemble

 

Oh I see what you mean. No apparent melting but I'll pull the contacts and try cleaning them up and re-assembling

 

Cleaned and re-assembled the pig tail as well as pulled the highbeam indicator bulb (it is standard not LED).

At ~1,600RPM the highbeam does not come on but the low beam flickers and dims.

Could it be that this is still an overvoltage issue? I'm still waiting for a more reliable multimeter in the mail, but my questionable meter is showing low 15's voltage at the battery.

 

15 volts at the battery points towards the voltage regulator being bad that is typical of an over voltage situation. Sometimes doing the test you see in the book of measuring the diodes doesn't necessarily show a bad voltage regulator. I have the same problem with the over-voltage put it in VR in the problem went away.

Bring the RPM up to 3000 and see if the voltage goes higher. The both of you are looking for is in the high for is 14 point eight volts.
You can try another meter but eventually you have to just learn to trust your equipment.

 

I recently changed out my R/R unit. With the original I was seeing voltage up to 17V, with a used one I got off eBay I'm seeing voltages in the mid 15's.

It sounded like having a bad R/R is rare, I would assume more so to have 2 in a row. Do you think I should pick up a third?

 

maybe get a new one

 

Plugged in a 3rd R/R unit today and saw the same results, 15V at the battery and the same highbeam flicker at ~1,600RPM (which remains on until the revs go above or below).

Either I'm very unlucky with R/Rs or I need to consider that maybe there's something I'm missing. Will be inspecting other elements of the charging system and seeing if there is anything out of place. This is turning into quite the headscratcher.