Topic: Upgrading The Charging System on a CB550

[dave500]

the stock units ive tossed in the bin have been faulty,it was easier to "upgrade" using a combination rec/reg from a boldor,if your doing a concours youll want the genuine thing,the rectifier and inbuilt type reg from an old auto alternator could even be used.

[cb750k77]

the only issue is that a 1157 LED to work for a tail light needs to be red... thats how LED's work! to make a "red" light it needs to be red... for a RED lenz..

so the trouble is that on our vintage honda's you have a clear part of the lenz... so if you install a red LED it will make your licence plate "pinkish red"

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95974

use that kit take it apart and install it in your stock tail light! use some hot glue and cut the "marker" light off the other side and you will have yourself a nice looking tail light

[HondaMan]

Hi HondaMan & Group
     Using a shunt type regulator when you can actually control the output of the alternator sounds very half assed to me. Mark by the way my Regulator is not a shunt type. At redline the regulator draws less than 1/10 amp and less under redline. There are problems with how Honda set the regulator up on the SOHC4 that need to be worked with but to just wire them wide open all the time?

There are some "reg/rec" units out there (OregonCycles comes to mind) that convert the alternator coils into a Kawasaki-like shunt regulated system. While this raises the battery voltage on the 500/550 bikes where we've seen it used here at SOHC4, it also severly increases heating of the windings, which has often resulted in failure of the enamel/epoxy insulation and shorted out the alternator coils. If the bike is only riden once in a while, like Saturday night to the local drive-in with friends, it may survive this method for quite a while. If it is used in commuter or touring service, it will probably see the alternator fail in less than one season, based on the last few years' experience we have here. 

You can "hot wire" the alternator to see if the regulator is acting up from burned/pitted points: jumper between the BLACK and WHITE wires at the regulator and ride for a while. This traps the field coil to full current to max out the alternator, and will not hurt it. It will also make the lights dim more at stopsigns, because the field load is not being dropped out at low speed.

Hi, Tom!
The "hot wire" technique is just a diagnostic thing. It's not intended to be left on all the time: just long enough to help identify the problem(s) that may exist. It will actually cause a lower battery charge if the (500/550) bike idles a lot, because the field coil is hot-wired to full current below 1800 RPM with this test, and the alternator makes less current than the field coil uses at that point.

The 750 is a whole 'nuther story: they have a sufficient alternator. 

[TomC]

Hi HondaMan & Grouop
     The "hot wire" as a check to see if bypassing the regulator gets the alternator going is a valid diagnostic tool. I was under the impression that You were saying that some of the regulators out there were running full voltage to the field coil all the time. Then shunting the excess output to ground. Maybe you can explain "Kawasaki-like shunt regulated system" in more detail.

Hi, Tom!
The "hot wire" technique is just a diagnostic thing. It's not intended to be left on all the time: just long enough to help identify the problem(s) that may exist. It will actually cause a lower battery charge if the (500/550) bike idles a lot, because the field coil is hot-wired to full current below 1800 RPM with this test, and the alternator makes less current than the field coil uses at that point.

The 750 is a whole 'nuther story: they have a sufficient alternator. 

     I brought up the CB750 to show that Honda could have done this correctly but choose not to. That extra 75 watts more or less makes a world of difference.
     TomC in Ohio

[HondaMan]

Hi HondaMan & Grouop
     The "hot wire" as a check to see if bypassing the regulator gets the alternator going is a valid diagnostic tool. I was under the impression that You were saying that some of the regulators out there were running full voltage to the field coil all the time. Then shunting the excess output to ground. Maybe you can explain "Kawasaki-like shunt regulated system" in more detail.

     I brought up the CB750 to show that Honda could have done this correctly but choose not to. That extra 75 watts more or less makes a world of difference.
     TomC in Ohio

Well, keep in mind that this bike was designed in 1968 and 1969: at the time, this WAS the state of the art. Kawasaki introduced the shunt style regulator in the 1975 KZ1000 bikes. Honda had the highest-output alternators on bikes, back then! 

The shunt-style regulators divide the 3 alternator windings into two different types. The field coil is run at 100% current all the time. One of the alternator windings is run at 100% output all the time, directly thru the rectifer to the battery. The other 2 windings are connected back to the next winding in the rotation sequence by way of an SCR. This device is triggered (or not) on each power peak by the voltage sensing circuit that is monitoring the battery voltage: as the voltage rises, the SCR is triggered earlier and earlier to shunt that coil's output into the next coil of the alternator, where it becomes heat instead of power. Thus, 2/3 of the alternator's output can become heat after the battery is fully charged. Most of the bikes that are set up this way also have the lights on all the time to help burn off the extra current instead of just making it heat. The alternators where this method is used must also have superior wire insulation and are usually NOT oil-bath type, so as to not catch the oil on fire in an electrical short situation. Honda's first version of this method was in the ill-fated CX500/650 twin series, and we all know how reliable those didn't turn out to be... 

This was done in response to the DOT laws in the U.S, circa 1972, that suddenly required all motorcycles have their headlights on. I think this law was struck down from the federal level, back to the individual states, in the mid 1980s again. The KZ1000 became popular as a police bike because it had this high-output shunt system (the Police Special had even more power) to run radios and other lights, too, which actually cools off the alternators in those applications (since less shunt current is sent back to the alternator). The CB750 fell out of police use primarily over this issue. Only the CB750A addressed it, in both the civilian and police versions, by adding the higher-current field coil to boost the CB750 standard alternator: it still used the conventional regulator to prevent engine fires from overheated windings. 

[dave500]

ive even used a rec/reg from a vf400,these have a permanent magnet field and dump excess to earth so the field was wired to the key on,it worked ok but after a year i didnt like the idea of the field on full voltage so went with the boldor one.

[TomC]

Hi HondaMan
     No difference in basic design between the CB750 and the smaller fours. Just a less powerful version of the alternator.

Well, keep in mind that this bike was designed in 1968 and 1969: at the time, this WAS the state of the art. Kawasaki introduced the shunt style regulator in the 1975 KZ1000 bikes. Honda had the highest-output alternators on bikes, back then! 

     Thank You for your description of the Kawasaki alternator system. I still think that it is halfassed! Fixing the lack of charging on a friend's KZ1000 is on my spring to do list. I guess that I had better download a shop manual for the KZ1000 and read up on this system.
     Clearly if the the voltage regulation is by wasting the electrical power that is above what is needed. Having the headlight on is a good idea. Except at idle when there is not much power coming out of the alternator.

The shunt-style regulators divide the 3 alternator windings into two different types. The field coil is run at 100% current all the time. One of the alternator windings is run at 100% output all the time, directly thru the rectifer to the battery. The other 2 windings are connected back to the next winding in the rotation sequence by way of an SCR. This device is triggered (or not) on each power peak by the voltage sensing circuit that is monitoring the battery voltage: as the voltage rises, the SCR is triggered earlier and earlier to shunt that coil's output into the next coil of the alternator, where it becomes heat instead of power. Thus, 2/3 of the alternator's output can become heat after the battery is fully charged. Most of the bikes that are set up this way also have the lights on all the time to help burn off the extra current instead of just making it heat. The alternators where this method is used must also have superior wire insulation and are usually NOT oil-bath type, so as to not catch the oil on fire in an electrical short situation. Honda's first version of this method was in the ill-fated CX500/650 twin series, and we all know how reliable those didn't turn out to be... 

     Clearly the Headlight on all the time business is the crux of the problem. I remember the time line as the law may have been 1972 but the requirement was for 1978. I am assuming 1978 model year. Honda made the switch in 1974 or 1975. Honda as far as I know did not make any changes to the charging system of any of it's bikes to accommodate the change to headlight on all the time. The DOT told the manufactures how to equip the motorcycles that they wanted to sell in the USA. The individual states require the headlight to be on or not.

This was done in response to the DOT laws in the U.S, circa 1972, that suddenly required all motorcycles have their headlights on. I think this law was struck down from the federal level, back to the individual states, in the mid 1980s again. The KZ1000 became popular as a police bike because it had this high-output shunt system (the Police Special had even more power) to run radios and other lights, too, which actually cools off the alternators in those applications (since less shunt current is sent back to the alternator). The CB750 fell out of police use primarily over this issue. Only the CB750A addressed it, in both the civilian and police versions, by adding the higher-current field coil to boost the CB750 standard alternator: it still used the conventional regulator to prevent engine fires from overheated windings. 

[750essess]

along with all this, does anyone have a good source of supply for wires/contacts/etc? I am wanting to build a harness from scratch to replace the shoddy wiring on my bike

http://www.vintageconnections.com/  for connectors and terminals, be sure to get the crimper tool

[cb750k77]

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

check out those guys they have some of the best corect and original connectors areound!!! i used them on my bike they look good!

[NickC]

Honestly? My bike is way past "original." I think I'm going to go with some GM Weatherpack connectors


I just need to find some good wiring source with all the colors I need.

[750essess]

I used weather packs on mine and work great but are kinda bulky. If I ever do it again I'm gonna use these:
http://www.summitracing.com/parts/SUM-900421/?rtype=10

[cb750k77]

Harley's use those!

[hcritz]

Hey Mark...
Would it be possilbe for the 550/500 guys to hand wire the stator with some additional wraps and bump up the amperage?
I know a lot of the Suzuki guys build their own. They are wired like the Kaws and are prone to failure.
I've read though the procudure...doesn't look like a lot of grins...but a doable project.

[750essess]

Harley's use those!

I know I know , but they are really nice connectors, they can be disassembled without special tools.

[HondaMan]

Honestly? My bike is way past "original." I think I'm going to go with some GM Weatherpack connectors


I just need to find some good wiring source with all the colors I need.

Nick:
Those Weatherpacks are nice connectors, but check the amperage on the ones you want to use first. Many of them (like the one shown) are for low-level sensor connections, max 3 amps. The ones that can handle the 13 amp rating for a 550 alternator are pretty big.

[HondaMan]

Hey Mark...
Would it be possilbe for the 550/500 guys to hand wire the stator with some additional wraps and bump up the amperage?
I know a lot of the Suzuki guys build their own. They are wired like the Kaws and are prone to failure.
I've read though the procudure...doesn't look like a lot of grins...but a doable project.

It is possible: it requires 10% LESS windings to make a higher field strength. This requires 10% LARGER wire to make it work out right, physically. Another option is to shunt the regulator's resistor with an additional one in parallel to raise the "low charge" current, but this is a poor bandaid. I don't know the wire size in those fields, but it wouldn't be hard to do something like that on my lathe: I could take a stock one, unwind and mark the core, then get new wire and rewrap. I did it on my Superhawk many years ago (1972?) to improve its poor output: I think they were only something like 65 watts stock. I got enough extra out of it that I could actually use the electric start twice a day without charging the battery every night, so it was worth the effort.

[NickC]

Honestly? My bike is way past "original." I think I'm going to go with some GM Weatherpack connectors


I just need to find some good wiring source with all the colors I need.

Nick:
Those Weatherpacks are nice connectors, but check the amperage on the ones you want to use first. Many of them (like the one shown) are for low-level sensor connections, max 3 amps. The ones that can handle the 13 amp rating for a 550 alternator are pretty big.

Those are rated up to 20amps. You can get them all the way up to 46 amps, but are bulky

[HondaMan]

Honestly? My bike is way past "original." I think I'm going to go with some GM Weatherpack connectors


I just need to find some good wiring source with all the colors I need.

Nick:
Those Weatherpacks are nice connectors, but check the amperage on the ones you want to use first. Many of them (like the one shown) are for low-level sensor connections, max 3 amps. The ones that can handle the 13 amp rating for a 550 alternator are pretty big.

Those are rated up to 20amps. You can get them all the way up to 46 amps, but are bulky

Ah, then the picture is deceptive: that connector body must be almost 1.5" wide and 3/8" thick or so.

[Blackhorse]

Honestly? My bike is way past "original." I think I'm going to go with some GM Weatherpack connectors


I just need to find some good wiring source with all the colors I need.

I'd definitely go with the Deutsch style connectors like the ones sold at Summit Racing. They are smaller and IMHO seal better. I work for Oshkosh Truck and they use both types on their vehicles.

Before buying from Summit check out LADD industries they sell this stuff by the piece and fairly cheap. http://www.laddinc.com/

There are also some special tools you are going to need as well. The most expensive being a crimper for the barrel style pins and sockets. This tool runs anywhere from $195 up to $400. If you find one that will do the job cheaper, let me know. You could also try a Harley dealer to see if they will crimp the wires for you for a small fee. The other tool will look like the one below and is used to pull the pins from the back side of the socket. They run about 50 cents a piece. There is no other way to get them out without boogering up the seal. Once the pins are crimped properly and engaged into the connector they can withstand up to about 35 pounds of pull.

The small hole you'll see on the barrels is not for solder it is a site hole to insure the wire is fully engaged into the pin before crimping. Deutsch also has a great website with some tips for assembling their connectors.

I teach this stuff to the military and to the commercial trucking industry, so if you have any questions holler.

[campbmic]

I've heard of a lot of people trying to get more juice out of their systems, I haven't gotten far enough to understand why yet. You can adjust the regulator to charge your battery over 14.5V so why don't people just do that?

Just wondering?

[Spanner 1]

I would never change-out the electromechanical regulator in our SOHC bikes.... much better system to charge and 'rest' the battery IMO, cycling the alt. allows cooling and cycling the battery will prolong its life and reduce 'boiling' off the battery fluid...... to prove my point I will, tomorrow, attach a voltmeter to my bike and ride it to SEE how much time the alternator is 'turned-on' to charge vs. resting and the bike running off the battery..... bet the 'rest' periods will be much longer than you think !!

[scottly]

I agree with Spanner. Don't try to increase the output of the alt, rather, reduce the load!!! We live in the age of LEDs!!!!

[bistromath]

campbmic: adjusting the regulator doesn't provide more alternator output. it just charges the battery higher. if your draw is greater than the power the alternator will provide, it will eventually drain your battery regardless of how high you have the cutoff voltage set.

spanner 1: actually, charging a lead-acid battery in pulses at a high current level will tend to boil off more electrolyte and charge with less efficiency than a slower "trickle" charge.

[hcritz]

Hey Mark...
I went back and reread the article on the Zuki forum...they do use a heavier wire with less wraps.
Even by hand, it doesn't look like too bad a project for a rainy day. Might be a way for some of the 550/500 guys to get a little more juice out of the alternator.
I finally found the issue with the charging system on the 81 750 C...ended up being the rotor. I have the factory manual and NO WHERE in it is the ohm reading for the rotor...has everything else. Funny...I have two of the engines for the DOHC and both the rotors read exactly the same. After spending WAY too much time on this bike trying to get it to charge...I poked around on the DOHC forum and found that the rotors are a very common failure and that the 2 ohm reading I was getting on both rotors was BAD!  Live and Learn!
You should be getting a check in the mail soon for the single Circuit ignition for the beemer...THANKS!
Ed

[TwoTired]

I've heard of a lot of people trying to get more juice out of their systems, I haven't gotten far enough to understand why yet. You can adjust the regulator to charge your battery over 14.5V so why don't people just do that?

Just wondering?

Because charging the battery higher than 14.5 or 14.8V ruins the battery, if not immediately, then drastically shortening it's service life.  The regulator is there to protect the battery.  Adjust it wrong and you defeat it's purpose.

Charging over 14.5v, where the battery is at full charge, begins an electrolysis process on the electrolyte, separating the Hydrogen and Oxygen the SO2H4 (sulfuric acid).  The electrolyte looks like it is boiling, it is actually out-gassing.  The plates begin to heat up, the electrolyte levels decrease, more heating, and then the plate separators melt/distort, permanently altering the battery characteristics, plates may actually warp and short if the abuse is carried on recklessly.

People who suggest raising the regulator voltage point to get more "juice" out of the alternator are projecting a "want" on to a device that is incapable of delivering that "want".  In essence, they simply don't have a clue as to what they are doing. (putting it quite bluntly)