Topic: checking my non-charging charging system

[Buffo]

Thank You for all your help TwoTired.

 

Buffo

[golden_child]

So, I am having the same problem with my bike, 72 CB750. The first month I had it 9april 2006) the the battery was lasting. I took it for a ride a week and a half ago and it died at a stop light by my house (I was lucky I was as close as I was). I charged the Batt over night and took it out the next day and it drained after an hour of riding. Lucky for me I felt the change in the engine and turned off the headlight and that gave me enough juice to get home. I could definiutely feel a change in the engine when I turned off the light. So, when I got back home I cut it off and let it sit for a minute or 2. I then kicked the engine to get it started again (no lights on) gave it a few revs the turned in the headlight and the engine stalled and died.

So, I've noticed that my headlight is draining my battery even when I am riding my bike (above 3k rpm). Can someone tell me where to start my trouble shooting? Should I have the batt checked first? It's a now a 2 month old wal-mart battery aka Never-Start, by a local motorcycle dealer.

a little history:
I bought the bike from I guy up in connecticut (over ebay). He has actually been very helpful so I have no reason to believe he was unloading a junk bike to me. The CB750 had been sitting in storage since Nov 2005 and sold to me April 2006. He said the only thing I would need is a new battery and an oil change. According to him it would get a tune up every year and a new battery. So, when I got the bike back home I purchased a new battery at Wal-Mart and filled it up. I did not do the initial charge, (a friend who was helping me said I would not have to worry about it).

In the mean time I was getting ready to pull the old battery out and figured "Hell, I check to see if the old battery still has a charge" so I flicked the lights and turn signals and they worked, to my surprise, I thoght the battery would be drained/dead from sittning. The only thing electrical that didn't was the horn (i just needed a new one). I didn't try to start the bike. So I changed the battery anyway and it worked well for about a month.

I am a new rider, so the first month or so I kept the revs kinda low and just putterd around the neighborhood. So a week and a half ago  I start feeling a little more confident in my riding. I wake up early on Saturday morning to beat any traffic in the area. I get to the stop light 250 yards away, down hill (a BIG hill) and then putter, putter, putter, silence (luckily at a stop light). I shut off all the electrics kick, kick, kick, wait 2mins, Kick,  Kick Vroooom. Clutch, first, a little gas, a little off the clutch, Dead again. Kick kick. nothing. let it sit and tried again and nothing. I left it there for a few hours and came back and nothing happened (I would have pushed it home but like I mentioned before it's a BIG hill). It just wouldn't start. Then I noticed that when I would try to sart the bike w/ the headlight on the the idiot lights were barley visible. So, I ficked to light on and off to see how much the difference was in brightness. It would go between somewhat visible and barely visible. So I took the batt out gave it a quick charge came back reinstalled it and the bike started right away. I got it home as quick as I could and charged the battery.

The next day, Feeling confident that everything was okay I took it out the next afternoon. Everything seemed fine lights on, signals working, horn beeping, me riding through Rock Creek Park. All of the sudden i could feel a change in the way the engine reacted to throttling and and changes in idle at stops. At stops I would give more throttle to keep the idle from dipping to low. At acceleration, if i would turn the thottle quickly it would putter a little then it would start to pick up, If i did it slowly it would get up fine. Next I turned the lights off and turned the throttle quickly and it was fine. So, I tried it with the light on again and the putter came back. I got a block from my house, off throttle, clutch in, down to second, slowly release clutch, dead to a rolling stop. I swear I didn't stall it. It felt like the bike just died. It was not violent like a, I don't know how to use a clutch, stall. Everything just died. So, I turned the headight off gave it a kick and it started. I went one block, headlight off at dusk and parked it in front of my house safely. Just to check it I started it up then turned on the headlight and the bike died.

any Ideas on where to start? I have the clymers manual and can't figure on a starting point. I would like to fix it myself if possible. but if I have to take it to a shop, then I will.           

Should I be checking the same type of stuff as posted here? if so, Is there a difference in the wiring harness and any of the wires?

 

[SteveD CB500F]

If you've read the posts on thisd thread, all  I can offer is my recent experience with Jim Shea's 750F1.

The battery was not charging at all and running at a total loss was fine for the first 40-odd miles....   Then the merest touch of the brakes causing the brake light to come on stalled the bike.

The fault was eventually traced to a wiring fault on the +ve feed to the regulator and hence to the field coil of the alternator.
Working backwards, no charge on the battery, nothing out of the rectifier, nothing out of the alternator. Not because the alternator was faulty, but these guys need voltage on the field coils to work. So, no voltage on the field coils, no output from the regulator caused by no INPUT to the regulator (now why didn't we check that first?)

The switched 12V to the regulator comes from the front of the bike by way of a black wire that also connects to the winker relay.

There was a break somewhere in the loom between the front of the bike and the regulator.

Fixed the connection, fixed the problem. 

[TwoTired]

GC,
The spark voltage is proportional to the battery voltage.  As you have experienced, when the battery gets low enough, the ignition doesn't develop enough voltage to jump the spark gap at the plugs.

In marginal weak battery cases, the lighting steals enough power from the battery to dip the voltage below the spark voltage threshold.

Your symptoms are indicative of a failed or weak charging system. You can either look at the electrics FAQ, or post questions for a step-by-step.

Charge your battery before doing system checks.  Kick start your bike (electric starter draws 150 amps) and get a votlmeter to measure the battery terminals with the engine reving at idle, 2000, 3000, 4000, and 5000 RPM.  Do the test again with the headight on.  Write the findings.
If the battery cannot reach 13.5-14.5 volts during some part of the above testing, your charging system has failed.  And, you will have to do further troubleshooting to determine cause. 
The process branches depending on findings.  So report back for the step-by-step.

[Jay B]

Buffo, I think oyu already found your problem. If you are getting charge with the black and white wires touching, you have a bad regulator.

[Bodi]

Buffo - the resistance reading is normal. The top contact on the relay gives full battery power to the field coil (the field terminal connects to the moving relay contact) when the battery voltage is low. When voltage gets a bit higher the moving contact lifts off the top contact and field power comes through the big wire resistor on the bottom of the regulator, providing some alternator power. If voltage gets too high, the bottom contact is connected to the field, it is grounded so no field power is supplied. In actual operation with a charged battery the contacts bounce around either between full and low or between low and off, depending on the load power.
If you measure resistance from F to G (or E) you'll see that when you push the contact all the way down you get zero ohms. Measuring from B (or I) gives confusing readings because you measure the coil and resistor - you can't really tell that the field gets grounded out at high voltage.

I installed an "Oregon" electronic regulator last month. It works great. I have some reservations about how the wires come out of it, I'm afraid they'll break off from vibration so I globbed silicon rubber all around them. I could have come up with my own using a car alternator regulator assembly, but I'm too busy to do that so I just bought it.

[golden_child]

GC,
The spark voltage is proportional to the battery voltage.  As you have experienced, when the battery gets low enough, the ignition doesn't develop enough voltage to jump the spark gap at the plugs.

In marginal weak battery cases, the lighting steals enough power from the battery to dip the voltage below the spark voltage threshold.

Your symptoms are indicative of a failed or weak charging system. You can either look at the electrics FAQ, or post questions for a step-by-step.

Charge your battery before doing system checks.  Kick start your bike (electric starter draws 150 amps) and get a votlmeter to measure the battery terminals with the engine reving at idle, 2000, 3000, 4000, and 5000 RPM.  Do the test again with the headight on.  Write the findings.
If the battery cannot reach 13.5-14.5 volts during some part of the above testing, your charging system has failed.  And, you will have to do further troubleshooting to determine cause. 
The process branches depending on findings.  So report back for the step-by-step.

Okay. I finally got around to it. Here are the numbers. I did the test twice. The first time the battery #'s seemed low so I topped off the charge for 2 hours and re-tested.

Headlight off.

2000- 11.97 / 12.22
3000- 11.98 / 12.23
4000- 11.98 / 12.23
5000- 11.99 / 12.23

Headlight on.

2000- 11.77 / 11.95
3000- 11.78 / 11.95
4000- 11.77 / 11.95
5000- 11.77 / 11.95

--golden_child

[TwoTired]

GC,
With those numbers it is clear that your charging system isn't working.  The bike will only run until the battery is drained.  You can run for longer periods if you disconnect the headlight fuse. However, the Electrics FAQ ought to help you find out what is wrong with it.  If you get stuck, confused, or need futher help, ask the forum.

We will need:
-Alternator stator resistance measurements.
-Alternator field resistance measurements.
-Rectifier diode resistance measurements.
-Evidence that voltage is getting to the field coil (white and black wires on Voltage Regulator).
-Verification that the interconnecting wires to components and the connectors, etc. are functioning without undue voltage loss, or with higher resistance than acceptable.

Happy hunting!

[Jerry Rxman Griffin aka MuthaF'er]

Two Tired,

From following all these posts you are helping with, there seem to be 3 things in common:

1) You're one hell of a guy for all your knowledge, patience, and help
2) Damn near everyone has, had, or will have SOHC4 electrical problems
3) There seems to be a common misunderstanding about the battery

Can you talk a little about the battery itself ? I think this should be a seperate subject itself within FAQ (if not already there).

Such as buying one brand vs another - pros and cons - will any battery do so long as it's the correct size ; Proper handling of the battery prior to installation - ie filling with acid & pre-charging pros and cons ; what to expect of the battery voltage-wise once installed if it's if not ridden much ; what to expect of the battery voltage-wise when you return from a ride ; how to properly charge a battery - ie 0.5A, 2A, 10A, trickle charge, float charge ; what to expect after a charge - ie what voltage should it charge to and what characteristics to expect as far as maintaining that "full" charge just sitting there ; how to determine if your battery is toast - ie cloudy appearing cells from sulfation, residual voltage loss/maintain ; when is it time to exchange your battery for a new one

I hope I haven't suggested something that you or someone else already have posted.

Jerry      

[golden_child]

Thanks TwoTired.

I'm thumbing throught the clymers book nd it says I need a rotor puller to to test the coil. Or at least get to what I need to test. I haven't poped the cover on it yet (i'm at work) but can I get the alternator off w/o a puller?

[TwoTired]

I'm thumbing throught the clymers book nd it says I need a rotor puller to to test the coil. Or at least get to what I need to test. I haven't poped the cover on it yet (i'm at work) but can I get the alternator off w/o a puller?

The CB750 has stationary field and stator windings that come off with the cover.  The rotor doesn't need to be removed for resistance testing.  In fact, testing the resistance of both the field and stator can be done from exposed wiring without removal of either component.

The field wires go to the Vreg (White and green), disconnect and measure.
The stator wires go to the rectifier (the yellow ones), disconnect and measure.
Same process for the rectifier itself, measure from the exposed connector.
Use the schematic diagram and a meter to verify connectivity.

Cheers,

[TwoTired]

Two Tired,
1) You're one hell of a guy for all your knowledge, patience, and help

Aw shucks.... (kicking the dirt)

2) Damn near everyone has, had, or will have SOHC4 electrical problems

ME TOO!!

3) There seems to be a common misunderstanding about the battery

Can you talk a little about the battery itself ? I think this should be a seperate subject itself within FAQ (if not already there).

Such as buying one brand vs another - pros and cons - will any battery do so long as it's the correct size ; Proper handling of the battery prior to installation - ie filling with acid & pre-charging pros and cons ; what to expect of the battery voltage-wise once installed if it's if not ridden much ; what to expect of the battery voltage-wise when you return from a ride ; how to properly charge a battery - ie 0.5A, 2A, 10A, trickle charge, float charge ; what to expect after a charge - ie what voltage should it charge to and what characteristics to expect as far as maintaining that "full" charge just sitting there ; how to determine if your battery is toast - ie cloudy appearing cells from sulfation, residual voltage loss/maintain ; when is it time to exchange your battery for a new one

I hope I haven't suggested something that you or someone else already have posted.

I agree batteries as well as things electrical have many common misunderstandings.  But, batteries aren't unique to the SOHC4.  Perhaps that's why we don't have a battery FAQ.  But, there certainly have been some prior discussions.
These links should answer most of your questions and many more.

http://vmaxoutlaw.com/tech/battery_maintenance.htm
http://yuasabatteries.com/faqs.asp
http://www.uuhome.de/william.darden/

I'm a fan of the Yuasa Yumicron batteries.  I believe their "sulfate stop" is actually EDTA.  Which does a fair job of reversing sulfation, which begins to occur anytime the battery is not maintained at peak charge.  You could add this to any standard battery to reap similar benefits.  I can't find it offered in the states online, though.  EDTA Tetrasodium is what to look for.

I'm also a believer in the automatic battery maintainer.  My current fave is this one.
http://www.chaparral-racing.com/Chaparral/productr.asp?pf%5Fid=321%2D2101Y&gift=False&HSLB=False&mscssid=ACDC644B34054D64A4EF311A90C41AEB

I plug my batteries into the charger whenever they are in the garage.  With routine auto maintainer use, a standard battery of just about any brand will last quite a long time.  If however, you do not use an auto maintainer, the Yumicron batts will last longer than a standard one, particularly if you routinely let the bike sit unused for weeks at a time.

I think this and the links cover it pretty well.   Pointed questions?  You still think we need an SOHC4 battery FAQ?

Cheers,

[golden_child]

Thanks for the info on testing. I'll check when I get home after work.

BTW,
Thank you for all your help and knowledge on this.

now back to reading the previous post.

[Jerry Rxman Griffin aka MuthaF'er]

Two Tired,

I do think we need some battery info in FAQ. The links are really helpful and the guys could get the answers they need.

Jerry

[golden_child]

Well, I still haven't gotten around to it yet. I hope to check sometime this week, except today it's raining. Can someone tell me if I should expect any fluid to run out of where the casing where the stator is? I only ask because I live in a condo complex and they just posted a notice of a a note with a bunch of things including "No Vehicle repairs on on condo property" By the way I hate living in a condo. The next place I buy is definitley going to have a garage or at least a car port.

If there is a possibility of this being a messy job I might have to take it to a shop.

[Bob Wessner]

Yes, you can expect some oil to come out. Shouldn't be much, but you would need a pan or something under it to catch what does come out.

[golden_child]

Thanks. I'll finally get to check the system when it dries out. My plan was to do it this weekend but the damn World Cup took up my weekend. I just hope I don't end up puting it off till July 10th.

I need a garage w/ a television.

[dusterdude]

world cup???whats that?

[golden_child]

Ok, I'm slowly getting there.

This what I have so far. Battery tested at 12.14v

Regulator: Black lead on Green terminal
on white wire: 11.41
on green wire: 11.46

Rectifier (looking at the harness the red/white wire on the top, left corner and the green in the top, right corner.):
Red lead on red/white connection:      OL / OL / OL
Black lead on red/white connection:  .485 / .456 / .480
Red lead on green connection:          .463 / .472 / .477
Black lead on green connection:         OL / OL / OL

I tred to get to the Stator and Field Coil plugs/wires but was unable to. I took the rotor cover off but the stator wires are tucked away behind the plate were the gear shift lever is. Is that normal? and do I take that cover off get to the exposed wiring? Also, should I expect oil to come out of here as well?

Thanks for the help and patience.

[Bob Wessner]

I took the rotor cover off but the stator wires are tucked away behind the plate were the gear shift lever is. Is that normal?

Yes.

and do I take that cover off get to the exposed wiring?

Yes.

Also, should I expect oil to come out of here as well?

Yes, should be a small amount though.

[TwoTired]

This what I have so far. Battery tested at 12.14v

I tred to get to the Stator and Field Coil plugs/wires but was unable to. I took the rotor cover off but the stator wires are tucked away behind the plate were the gear shift lever is. Is that normal? and do I take that cover off get to the exposed wiring? Also, should I expect oil to come out of here as well?

GC
No insult intended, but you're just not understanding the basics of electical troubleshooting or how test equipment functions.  Also, you do NOT have to remove the stator or the field coil to measure their resistance.  Their electrical connections are all accessible from the wire harness connectors.
Let's begin again and start with the basics, okay?

First, tell us the make and model of your test meter, post a picture of its face, or give a web pointer to where the unit is described.
Second, do you have a wire diagram for your bike?  You will need it.  Tell us where you got it.
Once this is taken care of, we can tell you where to place probes to gather and relay meaningful data.

So far, all I can tell you for certain is that your battery needs a charge.  Do you have a battery charger?

Cheers,

[golden_child]

Bob--
Thanks for the fluid info. I'll make sure to get an oil pan under there as well.

TT--
No offense or insult taken. I'm testing using a Fluke 73 Multimeter.

   

I do have a wiring diagram. It is from page 196 and 197 of the Clymers manual (M341) I am also getting visual information and additional instruction from Chapter 7 "electrical system"

I also do have a battery charger. It was purchased at Home Depot. It is a Husky branded automatic battery charger. it's either 2/6/10 or 2/10/55 either way I charge my motorcycle battery at the 2amp level. Sorry i couldn't find a bigger pic. I'll throw it back on the charger tonight.

   


Thanks for the help guys. I'm just trying to learn as I go along.

[golden_child]

I'll recharge and check again when I go home tonight. I hope I can find the harness which TwoTired is speaking of. I know where the regulator is and I know where the rectifier is now if I could just pin-point the other harness.

I know there are 2 large wires that are coming out of the engine just underneath the Airbox, I am correct to assume that one of those will lead me to the...

Wait hold on a second...The green and the white wire that are plugged into the top 2 positions of the voltage regulator are the Field wires I am am looking for, right? 

Wait give me another second... The yellow wires that I checked in the harness last night are connected to the Stator wires I was looking for, right? But not on the end I checked last night. The ones I checked last night were on the male end of the connector. I need to check the resistance on the female ends to get the Stator measurements, right?

Who knows, I could be wrong. I just kept rereading what TwoTired wrote in a previous post and it hit me after thinking about it all day.

If I am starting to get it can you tell me how to check the resistance? where does the red probe go? Where does the black probe go? Insert joke here.

thanks guys. I am trying hard to understand all this I swear I am. This is all new to me as is riding motorcycles.

[TwoTired]

Wait hold on a second...The green and the white wire that are plugged into the top 2 positions of the voltage regulator are the Field wires I am am looking for, right? 

You get an A!  Disconnect from the vreg and measure the field from those wires.  Measure from the green to the white wire.

You have the same meter I have.  Well, one of them.  Set to resistance scale and place the probe tips together.  The reading you get is the instrumentation measurement error (probe leads).  Remember this number and subtract it from any reading you make on the resistance scale.  This is especialy important for reading near zero ohms.

Wait give me another second... The yellow wires that I checked in the harness last night are connected to the Stator wires I was looking for, right? But not on the end I checked last night. The ones I checked last night were on the male end of the connector. I need to check the resistance on the female ends to get the Stator measurements, right?

If I am starting to get it can you tell me how to check the resistance? where does the red probe go? Where does the black probe go? Insert joke here.

Another A!  Pretty soon you'll be telling us how to do it!;D

Probe polarity is not important when measuring resistance of coil windings. The wires to the stator are yellow.  Measure from each yellow to the other.  Three measurements.  Then measure from each yellow to the engine case.

Probe polarity on the rectifier IS important.  Further, your meter has a special setting to measure diodes ---|>|-- . Use this setting to make the 12 measurments on your disconnected rectifier.  Yellow wires to green, both probe polarities.  Then yellow wire to Red/Wht, both probe polarities.

After we've verified your components are good we'll move on to wiring faults.

Well done!


 

[golden_child]

WoooHooo!!!! (pumping fists into the air)

Well here goes. I know I said that I would put it on the charger then take test at full charge but when I got home this evening I decided to take a few tests before I pulled the battery out for charging

Field Wire gets a resistance of 7.6

Stator, from the back of the Harness Green top left, Red top right. yellow wires starting left to  right 1-3.
1,2 : 1.3
1,3 : OL
3,2 : OL

1,block : OL
2,block : OL
3,block : OL

Rectifier, looking at male connectors, Red top left, Green top right, yellows on bottom giong left to right
Red probe on Red connector:
OL, OL, OL

Black Probe on Red Connector:
.498, .470, .493

Red Probe on Green connector:
.475, .484, .489

Black Probe on Green Connector
OL, OL, OL

Regulator, Ignition on Black probe on  green connector
Red probe on white connector 11.37v
Red Probe on Black connector 11.41v


Then I went back to the battery before I finally pull it out.

Headlight off
Idle:  12.06v
2k     12.3
3k     13.25
4k     13.65
5k     13.73

Headlight on
Idle:  11.68
2k     11.8
3k     12
4k     12.2
5k     12.25

The volts seem to want to climb more than in my previous tests.


I am slowly getting there, I think? Thanks for the help.