Topic: '76 Honda CB550F: Suggestions for Better Battery Life?

[magner]

First find where the white field is connected.

Here is the view under the shift plate and the wires that come out and a #$%*ty diagram i made https://imgur.com/a/gghFcZm

I can see the 3 yellow from the stator, and the green and white from the stator, and a green/red wire and a red wire from unknown components. All 7 go into the housing to go up to the top of the frame, but only 5 come out the top of the housing (2 towards the front of the bike, and 3 that go into the white wires for the rec) so I guess 2 must stop somewhere in the housing. Thanks for all the help, I’m really not sure what to do here. Thinking about taking it in to a professional...

[Deltarider]

Without having overread all the above, here a warning in general for CB500/550 owners. Where the wires exit the top of the left crankcase cover (aka sprocket cover), there's a chance the harness becomes chafed. Easy to address with some vulcanic tape.

[flatlander]

Thinking about taking it in to a professional...

don't do that, most shops won't have the knowledge to deal with these old bikes properly or won't take the time for it.
the advice you get here will help you to sort this out yourself, better than a shop could do. you will learn as you go, it will take some time and effort but that's the joy of owning a vintage bike.

[calj737]

First find where the white field is connected.

Here is the view under the shift plate and the wires that come out and a #$%*ty diagram i made https://imgur.com/a/gghFcZm

I can see the 3 yellow from the stator, and the green and white from the stator, and a green/red wire and a red wire from unknown components. All 7 go into the housing to go up to the top of the frame, but only 5 come out the top of the housing (2 towards the front of the bike, and 3 that go into the white wires for the rec) so I guess 2 must stop somewhere in the housing. Thanks for all the help, I’m really not sure what to do here. Thinking about taking it in to a professional...

Hang tight-
You have the 3 yellow wires that head to the Rectifier (I think Scottly saw and diagnosed those as turning to 3 whites). What you need to trace is the WHITE and GREEN that come out of that bundle from the shift cover. The GRN/RED striped wire is your NEUTRAL switch wire and that should run forward. There’s a BLUE/RED striped wire there too and that is the OIL pressure switch wire, it too heads forward.

So, locate the WHITE and GREEN. The WHITE is the field coil and it and the solid GREEN generally head to the Regulator with a solid BLACK from your key.

[scottly]

The green wire with the red stripe is the neutral light, and the blue wire with the red stripe is the oil pressure light. If they both function normally, it means the white and green field coil wires aren't connected. This would certainly explain why your charging system isn't working.  You will need to either slide the shrink tubing or cut more away to expose the area where the stock wires are spliced to the new to verify. Don't give up; you're almost there.

[magner]

Thanks for the encouragement! I’ve confirmed  that the neutral light and oil pressure light wires are cut and stop within the housing (makes sense as I don’t have those lights), and the white and green field coil wires splice each into new blue wires. Of course the new wiring harness uses this same blue wire for all wires so it’s hard to trace and I’m trying to avoid cutting open all of the harness housings unless I absolutely have to... I am certain that the field coil wires run to the front of the bike along with a bunch of other blue and black new wires. I studied the stock wiring diagram to try to deduce which wires are which. Out of these wires in that housing, 2 run into the coils (I assume these come from the points), 2 into the ignition key switch, and the rest run into the headlight bucket where they connect to the headlight switch, front brake switch, headlight bulb, tach, and the into the right handlebar control. Should I hack open the harness to see exactly which thing it runs to?

PS: Is it appropriate to message the PO about this, seeing as how he sold em a ready to ride bike which I have yet to be able to ride...

[BomberMann650]

Probably won't get much sympathy from the previous owner.

Some people

[scottly]

Try this: there are bullet connections for the white and green field coil wires under the shifter cover. Try to slip the positive meter probe under the clear sleeve on the white wire so it makes contact with the bullet, and connect the negative meter probe to the green wire the same way. With a charged battery, turn on the key and note the voltage.

Since it looks like the shrink tubing wasn't shrunk, you may be able to identify which blue wire goes where by pushing and pulling on the wire in question, and checking for movement on the other end.

I would contact the PO and ask how he wired the charging system; ask him if he wired it for an excited field system or a permanent magnet field. 

[magner]

With a charged battery, turn on the key and note the voltage.

With the key turned lights on and reading from the posts on the battery i get 11.9V, and reading from the bullets on the 2 field coil wires I get 10.6V

I was able to identify that the white field coil wire travels into the headlight bucket and solders into 3 wires that look to be original (2 blacks and a green with red stripe). These 3 wires go into a shrink tube along with gold/white stripe, red/yellow stripe, and black/white stripe; and all 6 of these go into the right handlebar control (which is stock). I guess this means there’s no regulator?? Could this be the issue? Not sure why that wire splices into 3 separate wires for the handlebar control...

[Deltarider]

I was able to identify that the white field coil wire travels into the headlight bucket

Are you sure? White wire in the headlight bucket normally is the headlight low beam.

[magner]

I was able to identify that the white field coil wire travels into the headlight bucket

Are you sure? White wire in the headlight bucket normally is the headlight low beam.

It’s not literally a white wire, as most of the wires in the harness are blue wires that have been spliced into the original colored wires. I found the new blue wire that the white field coil wire was plugged into and traced it to there.

[TwoTired]

Is the battery in the headlight?

White wire to alternator, attaches from the vreg.  Is that unit in the headlight?

On the stock bike, battery, vreg., and alternator are far from headlight.

I'd have to assess your bike is wired by rank amature, and wouldn't trust much of it to be correct.  Small wonder your bike doesn't charge the battery.

Methinks you'll need to make a wire diagram accurate to your bike.

You need:
Three yellow wires from alternator to rectifier need connecting. Rectifier green and red (minus and plus) need to connect to battery minus and plus respectively.  This connects power from alternator output to battery input.

Next you need to control the alternator output strength.  This is done with the voltage regulator.  It needs power from the battery during run time, stock bikes provide this via the black wire ( switched battery POS) and green wire  (battery NEG). The vreg then needs a green and white connection to the alternator, green is normally handled by frame and engine connections, ultimately connected to battery NEG terminal.  The white wire is the control line from reg to alternator field. The reg sends power to the alternator, so the alternator can make power based on the battery voltage level.  Battery low condition sends full battery power, battery full condition and the white wire voltage is throttled back, which reduces alternator output, in order to keep the battery from frying.
Clearly the wires colors only matter from an human I.D. Point of view.  The internal copper inside the sleeve all looks the same to electrons, which are mostly color blind.

Your job is to ensure your bastardized bike wire connections conform to proper design function.  You will also need to find the voltage regulator and rectifier components.  The stock bike had these as separate units. "Modern" replacements may have combined these functions into one unit, with yet another color scheme for wire colors.  You still need these functions if you want the alternator to charge the battery.  Locate them on your bike or purchase one to make your bike distance rideable on the roadways limited only by your fuel supply.

Good luck!

[BomberMann650]

In case Magmar needs a visual aid.

Here's Mr. Weeks diagram for the OMP vvrem4-sohc.  Simplified, shows where things should go in order to work.

[magner]

Thanks that diagram is very helpful. Is it safe to just go ahead and order a new reg/rec unit? I don't want to waste money if it's not the issue, but it seems like the one on this bike sucks anyway. It only has 4 wires plugged into it; the 3 from the stator coil, and 1 red wire from the positive post on the starter solenoid. It is not getting any wires directly from the field coil like in the diagram. There is no reg unit in the headlight bucket so I have no idea why its the white field coil wire is going into there and then soldering into the 3 wires for the stock right handlebar controls.

[BomberMann650]

I will shamelessly plug the Oregon Motorcycle Parts reg/recs as the lifetime investments they are.

At some point, it might be smart to order and M-Unit too.  Get an actual set of color coded wires in place of mystery blue. 

[Gene]

just logging on to see how it turns out. I have a 20 mile each way commute in Los Angeles/Orange County - ride the bike almost every day - no problems. Has to be the wiring as has been discussed here. Since the PO cut everything up, including the electrical system, your problem is in there somewhere.

[Deltarider]

In case Magmar needs a visual aid.

Here's Mr. Weeks diagram for the OMP vvrem4-sohc.  Simplified, shows where things should go in order to work.

Mr. Week needs to have another look at it. He mixed up lo and hi beam as far as color wires, but that's a minor detail here. Actually that diagram is quite instructive in its clarity. Thanks for posting.

[bryanj]

The unit with 4 wires is only a rectifier the regulator must be somewhere else

[Gene]

There is no reg unit in the headlight bucket so I have no idea why its the white field coil wire is going into there and then soldering into the 3 wires for the stock right handlebar controls.

I don't know your bike but I had a 360 where the regulator was bolted onto the frame under the engine. worth a peek?

[scottly]

With a charged battery, turn on the key and note the voltage.

With the key turned lights on and reading from the posts on the battery i get 11.9V, and reading from the bullets on the 2 field coil wires I get 10.6V

Disconnect the two field coil bullets, and setting your meter to the lowest ohm scale, measure the resistance across the white and green wires: this is on the ends of the wires that go to the stator cover, not the harness.

[magner]

With a charged battery, turn on the key and note the voltage.

With the key turned lights on and reading from the posts on the battery i get 11.9V, and reading from the bullets on the 2 field coil wires I get 10.6V

Disconnect the two field coil bullets, and setting your meter to the lowest ohm scale, measure the resistance across the white and green wires: this is on the ends of the wires that go to the stator cover, not the harness.

I’m getting right around 4.1

[scottly]

With a charged battery, turn on the key and note the voltage.

With the key turned lights on and reading from the posts on the battery i get 11.9V, and reading from the bullets on the 2 field coil wires I get 10.6V

Disconnect the two field coil bullets, and setting your meter to the lowest ohm scale, measure the resistance across the white and green wires: this is on the ends of the wires that go to the stator cover, not the harness.

I’m getting right around 4.1

The voltage reading may mean that the PO wired the charging system for a shunt type regulator, which diverts any excess voltage to ground. The resistance reading is a bit low; it should be about 5 ohms on a 550, IIRC. By running a constant voltage to the field, instead of reducing the voltage to the field to limit the voltage, the field coil *may* have been over-heated, resulting in the 4.1 ohms?
Next test: first, with your meter set on the lowest ohms scale, touch the leads together and note the reading. Next, unplug the connector with 3 white wires, and measure the resistance between all three wires on the stator side of the connector: A-B, B-C, C-A.

[bryanj]

Difference in battery voltage and field wire voltage is too high meaning a high resistance joint somewhere.

[BomberMann650]

Difference in battery voltage and field wire voltage is too high meaning a high resistance joint somewhere.

OP's rectifier is toast and the PO's rewiring is suspect anyway.

[scottly]

Difference in battery voltage and field wire voltage is too high meaning a high resistance joint somewhere.

OP's rectifier is toast and the PO's rewiring is suspect anyway.

Bryan, this may be a matter of the battery voltage dropping between the time with the lights on at the battery, and then at the field. Not a smoking gun..
Bomber, we have yet to determine if the rectifier is toast; first we need to verify the stator wiring. If it checks out OK, the next test is the rectifier.