Modern regulator-rectifier concern (CB400f)

[timeconsuming]

Hey guys

Recently threw in a modern regulator-rectifier in my 75 cb400f and after testing the voltage at the battery and I saw these results:

Bike off: 12.6 V - 12.7 V

Idling (1k-1,200 rpm): 14 V - 14.4 V

Revving (5k - 6k rpm): up to about 15.3 V at the highest, but steady around there while revving.

My main concern is (since I've been riding it around regularly) will this damage any of my electrical? If so what should I be looking out for? Warning signs, etc.

Second concern is that my old Honda regulator had a ground wire and the instructions with the modern regulator/rectifier said I didn't need to worry about grounding that wire, as the ground in the rectifier cluster would take care of it... Could this cable no longer being grounded be causing my high voltage? I plan on wiring in a ground cable to test but figured I'd ask while I'm here.

Also this leads me to believe that I need to get a good ground when mounting the regulator-rectifier but am not sure where to put it since it's bigger than the old rectifier (so it won't fit in the original spot next to the battery). Right now it's bolted to the side of the air box, which also currently holds my other electrical... The air box is bolted directly to the frame so I'm wondering if that's enough?

Thanks!

 

[Dingo]

Don't take my word on this, but your voltage levels seem fine, anything over 16V and you could fry your battery (probably).

BTW, what type of regulator-rectifier are you using? I might change that thing on 400f also.

 

[AlphaDogChoppers]

To begin with, you MUST ground your regulator.

Peak voltage a little over 15V is not unusual on these old bikes, though it is a tad high. Flooded cell batteries are OK with that voltage, because we are able to add water to them as needed. AGM batteries will dry out if run at voltages above 14.2V

 

[Bert Jan]

values seem ok, and like adc said, ground the unit. ALWAYS.

 

[bjbuchanan]

Your new setup should have a fine adjustment knob on it, the modern reg/rec setups usually do. You could lower it a little so you don't boil off the battery

Does the new unit ground thru its attachment or what, I'm sure there is a good reason it says you don't need the ground wire

 

[mydlyfkryzis]

See the green Ground wire? The regulator, if like this one, needs the case grounded to the chassis. The green wire on my CB360 is not the ground for the regulator, it is the ground for the rest of the green wires in the harness. I also ran a ground wire from that green wire to my neg. battery terminal so that it has a better ground then the chassis. High resistance in the grounds can cause the regulator to allow slightly higher voltages. Honda's spec for the stock regulator is 15.0 Volts, +/- 0.5 volts. So Factory charging system can be anywhere from 14.5 to 15.5 volts.

My stock regulator was at 15.5 volts. Even though it is "o.k." by Honda, I did go through a lot of electrolyte at those higher voltages.

 

[carnivorous chicken]

Your new setup should have a fine adjustment knob on it, the modern reg/rec setups usually do. You could lower it a little so you don't boil off the battery

Does the new unit ground thru its attachment or what, I'm sure there is a good reason it says you don't need the ground wire

I'm guessing it does ground through where it's mounted -- or at least it's supposed to. Depends on how/where it's mounted.

 

[mydlyfkryzis]

Yes. Goes to ground on the mounting bolt. I don't like the path to chassis ground through the tool case mounting bolts, as well as the bolts and rivets holding the regulator mount. I ran a wire from the mount to the battery negative to give an excellent ground. A high resistance path to ground will cause the reference 12V to be misread, and cause higher regulated voltage then desired. My mount had broken the weld (25 years ago) and I pop riveted the mount back to the tool case. The original regulator is wired to ground through that green wire. Since my harness is old, I ran the second wire to the battery, providing a better ground then the long path through the harness.

 

[timeconsuming]

Thanks for the responses guys, I'll snap some pics of my hideous wiring pile sometime soon to give you a better idea of what I'm working with, but I'm relieved to hear my voltage isn't too insane.

I found my reg/rec here: http://www.aliexpress.com/store/product/Voltage-Regulator-Rectifier-For-HONDA-CB350F-CB400F-CB500-CB500K-CB550F-Four-SuperSport-CB550K-Four-CB750-CB750F/605149_606899572.html

Was a little sketched out by the straight from china deal but I couldn't beat that kind of a price and it seems to work fine, though I'm probably in need of a lot better grounding is all.

 

[neevo]

I think that grounding wire is not required as the combined rec/reg unit uses the single ground that once went to one of the units (when they were separate) and shares it across both.

 

[timeconsuming]

Alright so today I did about a 50 mile ride and at the end of it, just a block from my place, my electric went dead while pulling away from a stop sign... Ignition off and back on, no signs of electric life.

I park the bike and grab my multimeter from my place down the street, come back and test the battery and it read 13.3V, with the ignition off.

So I'm assuming this has to do with the battery getting overcharged? The fluid was on the low end:

So do I just top it off with water and go about my merry way?

 

[Sonreir]

If you're reading voltage across the terminals, the battery isn't the first place I'd check. Sounds like maybe a loose connection or bad ground or something like that...

 

[AlphaDogChoppers]

That is a perfectly normal reading from a battery that has been in a charging condition. A battery has to "settle" for 24 hours before you can get a legitimate voltage reading from it.

 

[timeconsuming]

Haha I'm obviously pretty new to electronics and voltage. Thanks guys... really curious to hunt down the culprit for this power outage.

 

[timeconsuming]

Pretty embarrassed to admit that I found a split fuse this morning. One of the first things I checked but I guess not thoroughly enough.

It's a 15 amp fuse labeled as MAIN... any idea what caused the split?

 

[SONICJK]

ANybody have a shot of the stock reg/rect? i *think* mine came with a combo unit but I am unsure as its my first 400f

 

[AlphaDogChoppers]

Pretty embarrassed to admit that I found a split fuse this morning. One of the first things I checked but I guess not thoroughly enough.

It's a 15 amp fuse labeled as MAIN... any idea what caused the split?

Shit happens.
Replace the fuse. If it blow again, then look for a problem.

 

[mydlyfkryzis]

Let me tell you about glass fuses.
If the glass is smudged on the inside, the fuse is blown.
If the metal element is broken, the fuse is blown.
If the fuse looks perfect, the fuse may be blown.
Sometime the metal fuse element separates from the metal cap (on the inside). Externally it looks fine. The caps may be strongly attached to the glass too. But the fuse can be bad,

The only proper way to check a fuse is with a VOM. Check resistance un-powered, out of the socket, or check for battery volts on both sides of the fuse if it is powered up. Some fuses do not have power if, for instance, the ignition switch is off, or the lights are off, etc... Taking it out of the socket, visually inspect, then check for continuity is the only way to be sure a fuse is good.

And then, even if it checks out, it may be bad only when installed, or a certain angle, so replace it with a new, known good one, twice if necessary.

Those glass fuses are fickle. I spent plenty of time troubleshooting, thinking the fuse was good. It took as while, but I finally learned. Reagan said it about nuclear disarmament with the Russians : "Trust, but verify".

Trust a new fuse, but verify it with a VOM anyway....

 

[mydlyfkryzis]

I think that grounding wire is not required as the combined rec/reg unit uses the single ground that once went to one of the units (when they were separate) and shares it across both.

Neevo, if you look at the stock rectifier, it has 4 wires. The green wiore is the ground from the chassis. If you look closely at the bottom of the rectifier, you can see a copper ribbon that goes from the ground (green wire ) terminal to a ring around the mounting bolt. The green wire on the rectifier is not really the rectifier ground, as it grounds through the mounting bolt. The green wire is where the rest of the chassis green wires find their ground point. So the green wire on the rectifier plug/harness, should be grounded to chassis. so should the new rectifier body. My new reg/rect is mounted to the aluminum plate which is mounted to my tool box. The tool box regulator mount was spot welded to the top wall of the tool box, and the weld brokes years ago. I pop rivented the reg. mount to the tool box. Inn a addition, the tool box mounts to the frame with four bolts to the chassis, all are which painted. So between the mounts, rivets, and paint, I am not comfortable that the electrical path to the chassis (the battery has one ground wire going to a motor mount on the chassis). So I added an additional green wire, from the reg/rect mounting bolt, to the battery negative terminal.

This insures that the reg/rect has a good ground, and insures the wire harness on the rest of the bike is well grounded.

Most of the problems with these old bikes are bad electrical connections, and grounds in particular.

Reliability goes way up when you freshen and verify the connections.

 

[timeconsuming]

I swapped the new reg/rec with the old two pieces since I can't find a good mounting point to ground the new one to the chassis. Seems my stock charging system is actually in decent condition.

Definitely plan on making a little aluminum tray mounted under my seat for my electronics, glad to hear people have grounded their reg/rec on those successfully.