Charging System

[DesignBuild]

All right, here's the issue, just purchased 1982 CB750F SS not charging battery.

I have read a lot of post and such regarding this issue but haven't ever really gotten a good answer as to why the thing doesn't work.

I have charged the battery 12v, holds that after several days.
checked continuity on stator, all three read good. Checked voltage from stator while running, plenty of AC charge (can't recall the exact reading)
brushes have plenty left, if not brand new.
while running battery reads 13-14v when given a little throttle (would lead me to believe the R/R is doing its job)
checked for corroded grounds, doesn't seem to be any. (i have yet to actually pull the DVM out again and check to ground)

one device that i did find, that i cant single out on the wiring diagram for the life of me, here - http://www.oregonmotorcycleparts.com/Diagrams/CB750F_dohc.jpg
is this little round thing with a Grey, Green/White, and Dark Green (ground) coming off of it. Problem is the Dg (assuming this is the ground) isn't grounded. I don't know what this thing is or if it needs to be grounded or not so if anyone knows what im talking about, info would be appreciated.

if anyone has any ideas, that can keep me from inevitably replacing the whole charging system and still have the issue, it would be greatly appreciated.

Btw, I'm actually a Electrical Controls Designer, so don't be afraid to use big words.

Thanks.

[cbRider]

Hey electrical Controls Designer, how about a picture of that little round thing with a Grey, Green/White, and Dark Green (ground) coming off of it? So we can all see what you're looking at.
It sounds like your charging system is okay.

[DesignBuild]

Haha, I would of posted one earlier but I'm at work busy "Controls Designing" I'll snap a few pictures when I get off work, and try and figure it out myself too, I only spotted the thing on lunch so I didn't have a whole lot of time. As I recall it might only have the Green/White and Grey wire coming from it, it almost looked like the ground was coming from somewhere else in the harness.

 

[DesignBuild]

the ground does appear to pop out of the harness that the other two wire go into, so it might not go with this device. I would still like to know what it is though, since there doesn't seem to be anything that matches these wires on the diagram. (these are the best pictures i have until i get my camera to where my bike is)

thanks for the help.

[Polymer-2]

Thats your turn signal flasher.

[cbRider]

Sure looks like that thing is your turn signal flasher. That green wire goes to the Voltage Regulator / Rectifier. Don't know it's function, it isn't connected anywhere. I wonder if it could be a test lead. Maybe someone can fill in here.

Karl

[Polymer-2]

Here is the link to the charging system section of the manual. PDF


http://www.fileden.com/getfile.php?file_path=http://www.fileden.com/files/2008/11/1/2168673/16%20Battery%20and%20Charging%20System.pdf

[DesignBuild]

i thought at first it was the turn signal relay also, but the other wire didn't match up (it appears to be Grey) although seeing as how the bike is 26yrs old it could just be faded all to hell.

Thanks for confirming what it is.

I still wish i knew where that (Dg) went, its got a connection on the end of it, i suppose its possible its a test. I'm going to run some point to points with the voltmeter and see if i can match it to anything, if not i'm just going to ground it and see if that fixes anything.

If that doesn't work i suppose ill have to start hack and slashing my wiring harness till something stands out at me, be it a short or something. It's frustrating considering everything else is checking out.

I'll post what i find.

thanks again.

[Polymer-2]

DON'T CUT YOUR HARNESS! That rarely works out. That wire is a ground but is left unconnected. I think it'd a ground for a 3 terminal flasher. Make sure your regulator is grounded (dark green at the regulator) and has power to the black wire (I think. Check the diagram) with the key on and do the tests in the manual.
You said it's 14v running. That should charge the battery. Put a the meter in series with the battery without it running and see if something is drawing power with everything off. If so suspect regulator.

[cbRider]

Thanks polymer for the link to that charging system section of the manual. PDF
It's a good thing to have.

Karl

[DesignBuild]

alright alright, i wont cut anything till i check everything again.

i have tested the battery while on the bike after 2 days time left sitting and it holds its charge though. but i will check out that ground from the R/R and make sure the black is hot.
and before i cut anything i will most likely clean all my grounds and make sure none are corroded and they have a good connection, i should have some time to work on it today so ill post afterward.

its possible that it just comes down to my battery draining ridiculously quick when the engine isn't running and the key is turned or is at idle. That was one thing i found odd when i had the DVM hooked up, it was draining at about .5v a sec without throttling, i thought this was just because my idle was too low though, and since have brought my idle up to 1k-1.5k, but ill investigate that some more.

 

[DesignBuild]

alright, checked some stuff out.

grounds are good, R/R is grounded, R/R black is hot.

removed the headlight with key on and bike off, slow decline in battery (expected because neutral and oil light are still on)

ok. so i'm running low on ideas of what could be wrong.
If i understand what the R/R does though is that it is two parts housed in one piece. regulates flow from stator to battery to create charge, then keeps flow from reversing and heading back to stator from battery to avoid draining the battery. Right?

So if that is correct, is it possible that the part that brings flow from stator to battery is working properly (seems to be since i get a 14v charge) and that the part that keeps it from flowing backwards is broke, creating a leak while the bike is on and drains my battery?

that's all i got, and that only came from the post polymer made about charging system testing.
other than that im spent, help?

[tj]

hi are you sure brakelight switch is not stuck on ive seen this a couple of times on hondas (yes i worked in a honda shop) i know it sounds odd but the charging system wont overcome the brakelight stuck on.just a thought.good luck T J

[DesignBuild]

Thanks for your reply and interest, but i had thought this thread came to more of a close, i guess not.

it's been awhile, but this ended up being a bad battery, it was just at the end of its life so it was hard to diagnose.