The Honda CBX Charging System. Why are there so many problems?

The system goes back to the 1970's and was designed for easy removal & replacement, being externally mounted with quick release connectors. Over the years, we have found that the electrical wiring system connectors allow moisture to get deep down inside the connector where the ends come together. Over a period of time they will build up corrosion to the point that electrical current has a difficult time flowing through these connectors. This is the beginning of a problem -- as the resistance builds, so does the heat, which can cause the insulation on the wire or plastic connectors to melt.

Also, the charging system is clutch-driven, with slippage intended from idle to full throttle to help counteract the violent acceleration rate of the CBX engine. Clutch plates, springs and thrust washer are all designed to have a certain amount of slippage. So how does this interact with the charging system? Adding to the entire mechanical system are even more parts, all contributing to the ability (or inability) to maintain the battery charge and the rest of the electrical system.

One component is the regulator/rectifier acting as the controller for the charging system. Trying to keep the battery fully charged while having to compensate for the demands of the bike and its accessories. And of course the, by now infamous, alternator brushes that complete the circuit through the regulator/rectifier to allow charging are another item.


How to isolate the fault:

Some of the best information sources other than the Technical Manual have been posted on the Internet. A link to the manual can be found through our own CBXWorld site. One other link is:
I would have to say it is a very good tool to add into your Technical Manual. It did isolate my problem and I have seen that there have been well over 90 downloads of the Fault Finding Flow Chart. Adobe reader program is required to view the chart.

When using the Technical Manual one has to remember that digital multi-meters were not being utilized back then, so most of the electrical measurements were on an analog-style meter (Voltmeter). When performing the required test, problems can arise with a cheaply made digital meter, causing you to replace a perfectly good part. This can be a problem with an inferior meter when performing a diode check, for instance.

Where does one go for replacement or rebuilt parts?

There are two places that I have found on the Internet.
On the East coast, there is Rick's located at:
and for the West coast, Electrex at:
They both provide rewound rotors and stators or will rewind yours and will offer some type of a guarantee with their workmanship. Some parts are still available from Honda: I was able to get all of the seals and the inner bearings, which seemed to be expensive compared to other sources that I found after receiving the ones from the dealer.

What can you do to help the system?

One of the major items is to inspect your connectors. While it will take sometime to check all of them, it can save money in the long run. After my charging system failure I performed a check of my connectors and had found that the insulation on one of the wires had melted off, and the connector directly from the alternator had melted also! So, after making a new wire harness from the relay to the main junction and finding the replacement connectors, I had to cut away the melted plastic from each of the wires and its mating connector to save the pins and sockets. I needed to clean all of the corrosion from them and began with removing each wire using a small screwdriver and a dental pick. Once each wire and pin was removed from itís connector, I used a Dremel tool with a little wire brush attachment for the cleaning process. After cleaning each pin and its mating connector I checked the fit. Again, a loose fit could cause trouble down the road. After the fit was verified, I coated each and every connector with a dielectric grease. I did find several connectors that had a buildup of corrosion, from behind the headlight to the main junction next to the battery. I believe that they were causing or about to cause a problem with my electrical system, so now I don't have to worry and will perform a general inspection during normal maintenance of the bike.

Is there an alternative?

Yes, there is a replacement alternator assembly (complete with internal Regulator/Rectifier) on the market -- it is expensive, but nothing comes cheap today anyway! I went to the new alternator after thinking of what I had done to my bike during itís upgrade and what I really wanted for a charging system. As many of us have put newer technology components into our bikes, myself included, this was one of the biggest reasons for going with another product. I made this decision only after looking at where I was with the older charging system, adding up the cost of each of the components from the rotor, stator, brushes, bearings, seals, and the regulator/rectifier. I was beyond the cost of a newer technology. Sure, some of you may say correctly, that it wouldn't all go out at once. But the answer to that is why should I have to worry every time I wanted to be out riding if I don't have a spare regulator/rectifier or replacement brushes with me? Then there are still the clutch plates and spring that drive the older style alternator, as opposed to the new style being a direct drive with dampening cushions to take the reaction to the throttle. The output is 430 watts (335 to 350 from the stock alternator) of solid state technology, and with the new AGM-style battery, your upgraded charging system will now be one of the more foolproof modifications you have done on your CBX!

Technical Information on this Alternator.

Alternative alternator designs have been around for a while. I think the Australians were first to come up with this. They used a modern Kawasaki ZX7 alternator with integral regulator and made a custom adapter plate with a simple "dog clutch" drive with rubber dampers. This actually used elements of the original friction clutch drive. In Germany a guy named Stefan Jung either came up with his own design or copied it.

The Kawasaki alternator used in the Jung setup for the CBX is the one from the ZX7R model. The alternator used on the ZX7R is a functionally standard type of electromagnetic rotor type with a 3 phase stator winding in the frame. The rotor assembly is mounted on a rotating shaft (approximately 1/2" diameter). At the output end of the shaft are two small brushes mounted in a brush block, riding against the commutator rings. Also mounted in the output end of the alternator, and positioned on either side of the brush block, is the rectifier unit and, on the other side, the regulator unit. The rectifier unit is identified by the three leads (from the stator windings) soldered to three small tabs. The regulator unit is identified by a large, round power transistor in the center surrounded by a small heat sink (with fins). The alternator uses a common metal ground internally to connect these three units together. The final regulated/rectified output is a two lead cable that plugs directly into the wiring harness and, from there, up to the battery and ignition circuits.
Because the commutator rings are quite small in diameter, brush life is quite long. All of the major units are replaceable. Checking with a local Kawasaki dealer reveals the replacement costs for the major units are quite high (even with a discount).


How hard is the installation?

It will be one of the easiest modifications that you've installed on your bike -- sure, it's a little work, but doesn't take a lot of tools and involves very little time.

Remove the battery and disconnect the regulator/rectifier from the quick release connectors, as that is one piece that will not need to be used. You may desire to keep the regulator/rectifier installed for future conversion back to original. If not, prior removal of the battery bracket will improve access to the bolts that hold the regulator/rectifier. Take off the original alternator from the motor. Also, remove all of the remaining drive pieces (clutch plate, spring and the thrust washer) as they will not be used when installing the new style alternator. The only seal/o-ring that is required is the big one that goes around on the backside of the old style housing. Once the new alternator is installed you will plug it directly to two wires in the connector from the main harness where the regulator/rectifier was plugged in. Now reinstall your battery box and battery and you have completed the installation. Fire up the engine and verify charging with a good quality volt/ohm meter. After this final check, you are ready to ride trouble-free on your CBX!
My feeling behind this article is to let others know that there is another charging system that can be used on their CBX.

Thanks to Editorsí staff once again, for all of their time and input.