Topic: Jumping the headlight ON/OFF switch??

[Chuck Hahn]

Bike in question is a 74 CB550 FOUR.. I had a post a few months ago about low charging with the headlight on versus with the headlight switched off.  Headlight on and around 1500 i see around 12.59 at the battery. switch the light off and it jumps to a respectable 13.89 in a few seconds.

I was wondering is there a mod to the headlight ON/OFF switch that will allow the 13.89 regardless what position
the switch is in??   If so what two wires do I jump together to achieve this???

[Chuck Hahn]

Just tried a few things as the manual says in the charging section.

First, OHMS between the green and white wires from the field coil reads 1.1

Second, I unplugged the stator wire at the electrical panel and set the meter on AC VOLTS.  Hooked the black wire from meter direct to the battery negative and started the bike.  At each of the 3 yellow stator wires it reads 45 at idle and runs up to 80 at around 4500. If Im understanding it right, the stator is throwing good voltage, but the field coil is out of spec and is bad???

[madmtnmotors]

3-position micro toggle from Radio Shack. I used the center position for "Off"

[Chuck Hahn]

Yeah....not gonna do a butcher job to my bike.  Sorry.

[madmtnmotors]

Butcher? 

It fit the opening in the stock control housing. I can put a stock switch back in its place if I were so inclined. In hindsight, I would have painted the base black and it would be a near invisible mod. Sorry to imply that you might be inclined to stoop to my level... 

[Chuck Hahn]

First off your on the high / low switch which wasnt my question.

Secondly, the right hand switch housing has a switch that allows one to turn of the lights..headlight, tail liight, turn signals and dash go out when you flip to the off spot.

I dont want to have to turn the lights off while riding just to get a good solid charging number out of it is my goal here.

[Chuck Hahn]

Calj737...  this bike is so nice I would like to keep it stock original as much as I can.  I had my laptop right on the bench and did the checks by the letter.  I am so close to finally being able to ride it before winter weather sets in and I cant trust it wont leave me stranded somewhere..

[Chuck Hahn]

This is the first thread I started a while ago.  Headlight is the right one, I have cleaned all the connections in the headlight bucket, replaced the rectifier with a new original Honda part off Ebay..so the rectifier is for sure not the issue.

http://forums.sohc4.net/index.php/topic,160511.0.html

Checked the gaps in the points on the regulator and they are spot on per the manual.  Regulator does change the charge at the battery but with the adjuster screw all the way in it still isnt getting anywhre near what the manual says I should be seeing

This is the manual PDF I am using...

http://www.dotheton.com/downloads/CB500-550_Manual.pdf

[madmtnmotors]

I dont want to have to turn the lights off while riding just to get a good solid charging number out of it is my goal here. thats a lot more clear. Probably a better explanation than your original post.

+1

If I'm understanding it right, the stator is throwing good voltage, but the field coil is out of spec and is bad???

If I understand the charging system correctly, this is not possible. For the stator to be "throwing good voltage" requires a good magnetic field from the field coil. If the field coil were weak, voltage from the stator should also be weak, no?

At this point, your assessment seems to be field coil. No switch positions are going to resolve your charging issues if you also want to run your headlight.

+1

[Chuck Hahn]

Diagnosis on the rectifier.    It wasnt reading anything reverse or forward. The replacement rectifier was new out of the box and the diodes OHMed like the manual said it should. The old one had no readings what so ever either way.

[madmtnmotors]

Diagnosis on the rectifier.    It wasnt reading anything reverse or forward.

That sounds more logical than the field coil based on the stator output, but optimistic based on the charging voltage you are seeing at the battery. If the rectifier were failed in the way you descripe (no voltage pass through) then how are you getting any charge voltage to the battery at all?

Headlight on and around 1500 i see around 12.59 at the battery.

According to the manual you linked to in this post:

This is the manual PDF I am using...

http://www.dotheton.com/downloads/CB500-550_Manual.pdf

Your charging system is working properly at 1500 rpm. What values are you seeing at 3000 or 4000 rpm? From what I see in the manual, is that the CB550 is similar to the CB750 charging system in that they both operate at a loss below 2500 rpm (or thereabouts) and don't really start charging well until about 3000rpm. Just the nature of the beast. If your voltages are good above 3000rpm then you need to spend less time puttering around town and spend more time out on the open road "letting 'er rip". 

How are you testing the rectifier? Are you using a digital meter? If so, are you using the "continuity" setting or the "ohms" setting? Many digital meters have a continuity setting because they are not sensitive enough to reliably test continuity across some diodes. The diodes only have to pass voltage one direction to convert alternating current from the "alternator" to direct current to charge the battery. 

[b52bombardier1]

Why not test the rectifier in action while mounted on the bike with the engine running?

With the motor running,  place the multimeter probes on the battery. Flip the multimeter knob to AC volts and see what she says. Hope for around .1 volts AC or less - a tiny amount. Much more AC than this will eventually kill a DC loving battery.

This will directly tell us how much AC is leaking past the rectifier diodes with the electrical system in normal operation. Go to half throttle and see if it gets better or worse.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk

[b52bombardier1]

I understand that his stator is providing 45-80 volts AC as an input to the rectifier. For the health of the rectifier, I'm interested in how much of that AC leaks past those old diodes as a rectifier output to reach the battery.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk

[madmtnmotors]

I'm interested in how much of that AC leaks past those old diodes.

replaced the rectifier with a new original Honda part off Ebay
http://forums.sohc4.net/index.php/topic,160511.0.html

[b52bombardier1]

Yes, but he could have checked his old rectifier using a much less invasive test while it was still mounted on the bike. Then do a rectifier diode continuity test if he saw much AC leaking towards the battery.

I'm trying to make our lives easier around here for electrical system checks, not harder.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk

[madmtnmotors]

I'm trying to make our lives easier around here for electrical system checks, not harder.

As am I. 

We are still waiting for DC voltage readings at the battery at 3000-4000rpms. At 1500rpm the voltage readings at the battery are within spec. My contention is that there may not be a problem with the charging system at all, but merely a perceived issue based solely on the voltage readings at the battery at 1500rpm, which again, per the manual, are well within spec. 

[rotortiller]

Why don't you guys put a solar switch on it. LOL Go to home depot and rip apart an automated flood lamp
At least you won't go off the road in the dark when you mess up  switching to high/low!

rt

[Chuck Hahn]

Everything went over again for then tenth time..by the book and by the links that were posted in my other thread. everything checks out 100% though......rectifier check with the meter on the diode setting is as it should work.  Stator checks right when OHMing it out and shorting to ground.   Holding a feeler gauge against the alternator cover and it gets magnetically sucked in ike the turtorial says should happen  etc etc etc.  Adjuster screw on the regulator does change the voltage at the battery but it just will not go above 12.7 volts at 5000 RPMs....and thats with the screw turned in as far as it will go.

So I am gonna replace the reg with this one from Oregon.  Second one down here....

http://www.oregonmotorcycleparts.com/SOHCfours.html

[madmtnmotors]

will not go above 12.7 volts at 5000 RPMs....

That's what we needed. Something is definitely not working properly. Based on the AC volts from the stator I would agree that the regulator would be the most likely culprit.

[Deltarider]

With the motor running,  place the multimeter probes on the battery. Flip the multimeter knob to AC volts and see what she says. Hope for around .1 volts AC or less - a tiny amount. Much more AC than this will eventually kill a DC loving battery.

Not to hijack this thread, but could you inform us a bit more on this. I did search the internet, but I've not found any confirmation of your method so far. Today, out of curiosity, I did what you suggest and @ 3000 rpm my DMM measured 29 volts AC.
Now, if this is alarming (and you suggest it is) this could be because of my old battery which is near it's end (actually I'm surprised of it's stamina). It could also be that one has to perform your test with an analogue meter which dampens eventual spikes. BTW, there are a lot more situations where an analogue meter is much easier in use. Oh... and 29=14,5 x 2. I hope to learn more.

[b52bombardier1]

Measuring 29 volts of any kind of power at the battery is not good.  Take your meter to your car and start the engine - take the same measurement at the battery.  This will allow you to be confident that your meter and knob settings are working correctly. Try DC first and then flip the knob to AC.  What do you see?

  At idle, hope to see around 14 - 14.5 volts DC.  And let's keep our fingers crossed that you see less than .1 to .2 volts AC.  At least this is how things work using my Fluke 17B multimeter.   I have heard that the lower priced meters struggle with measurements of AC. The low end Harbor Freight meters struggle with AC and it is not until you get to the $20-25 Centech models that it seems to work for AC measurements.

Rick

[Chuck Hahn]

This is a Craftsman fancy smancy digital meter Im using.

[Deltarider]

  At idle, hope to see around 14 - 14.5 volts DC.  And let's keep our fingers crossed that you see less than .1 to .2 volts AC.  At least this is how things work using my Fluke 17B multimeter.   I have heard that the lower priced meters struggle with measurements of AC. The low end Harbor Freight meters struggle with AC and it is not until you get to the $20-25 Centech models that it seems to work for AC measurements.

This is what I also read elsewhere. I don't have a Fluke or similar and I think that explains it. I have a couple of cheapies that have AC (200 and 700V scale). I could try the other 2 but I think the result will be the same. Then I have a special automotive DMM with dwell, tach, duty cycle, but that one doesn't have AC. Doesn't need it as it has a diode test.