The International CBX Owners Association

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At 23000 mi I replaced the brushes, they were about all gone, did not have any warning problems, except dash voltmeter wouldn't show charging until several miles and rpm's up, then it would show 13.5 or so. Now, at 24000 miles, stock voltmeter goes up and down and shows 14 volts above 2000 rpm, but only shows 12.45+- charge at battery terminals when checked at all rpm's. A new battery lost its charge and wouldn't start bike when hot. I suspect alternator clutch problem; what should I do next? Should I relace both clutch plates, spring and washer? Is there a test(s) I need to do before I start buying parts? Is there a standard fix done countless times by brilliant CBX owners?

andy,

Try replacing the battery with another one,almost sounds like the battery lost a cell----been known to happen to an otherwise normal-working battery before.If you lose voltage,the rotor field will not energize properly,causing the wide flux of voltage readings.Also keep in mind that the stock Honda voltmeter reads at least 1 volt low.....all of them I've seen do that.Use a good volt/ohmmeter for checking voltage.I'd rule out electrical stuff before you condemn the clutch & spring.

Andy, a couple of things.

If you replace the battery (good idea, as Mark suggested), get a Westco AGM sealed battery from 'batterystuff.com'. According to my records, it's a type 'WC22' ($74) and, at the time, they 'free' shipped it UPS to me. It will give you cranking power you won't believe, won't discharge as fast as a lead type, and should be more rugged (stats not in on that yet). As Mark said, a bike battery (even the best) can suddenly loose an internal connection and just go dead. No matter what you get but particularly on an AGM, be sure to put it on a charger FIRST and fully charge it (read the charging specs on the battery); I have heard that AGM types, if not fully charged FIRST before use, can/will develop 'memory' and will not fully charge after that to the full 12+ volts.

As for diagnosing your problems, look through ALL of the Tech Tips here and on other boards and you will see TONS of 'how-to' to check out your system. You didn't say what year bike you have but the first thing I would do is detach and reconnect (several times) the two connectors from the R/R (one to the alternator and the other to the wiring harness). This will 'clean/wipe' the connector surfaces and remove most of any contamination that, after 23K, you surely will have in there. Contamination, in my opinion, is the 2nd most likely of failures, after a flat-out failure of one of the components. Contamination will cause other components to fail so start there.

I agree with Mark, eliminate the electrical before you go after the clutch plates and spring.

Let us know how you fare so we can file it away.

Thanks

I replaced the battery w/ good fully charged matching spare at local shop (think its a gold wing, the negative terminal screw on top instead of side) symptons same although it hasn't gone dead on me yet as I have only ridden once for 50 miles since it went dead 1st time, and battery still not charging over 12.4 + - volts read at battery terminals at ALL rpm's. Voltmeter on dash all over the place from 8v w/ key on (not running, lights on), goes right up to 14v over 2000 rpm and stays there until idle. Then dash voltmeter reads 12.5 or so. My pride and joy is an 81. Only non-stock items are Hondaline clock and air temp gauges, they've been on for 2 years. Immediately before this problem occured, I did valves, plugs, oil, cam chain adjustment....and washed it . The plug gangs under rt sidecover have been disconnected and swiped, local mechanic checked in all those connections, detertmined regulator ok. Said alternator not putting out enough. He actually worked on 81 school bikes so he was familiar working on it although probably did not come across alternator clutch problem on school bikes. Doesn't the alternator clutch fail on ALL CBX's eventually?

Today I pulled the alternator, very ez. Clutch plates very scored, in fact 10% of grooves non-existent its so worn! Ordered new plates A + B, spring, seat, washer and special washer using parts book. Now I await finding out what is discontinued.

Andy, almost everything is discontinued from Honda. The problem in the clutch is not necessarily the plates. they always look worn after some 100 miles. The problem really is the spring, which sets and does not provide the load necessary anymore to force the plates together. Look for a good used set with an O.K. spring. Check the manual for the service length. If no luck, send me a pm after Oct 20, I have a couple of sets left. Just can't do anything before I leave and come back from a trip. You may also try Rick Bentley. Now that you met him at Mid-Ohio, you should have some connections!!!

Found another problem....oil in alternator, several teaspoons poured onto the floor, inside of the now-exposed engine wet w/ gritty dirty oil (that crap is running around my motor?). Since I acquired my 81 four years and 23,000 mi ago, the breather hose from the alternator to airbox has always been misty w/ oil so this has been going on for a long time. Never thought it was a problem (more like "wished" it wasn't a problem) until now. What part # is the oil seal and how is it replaced? Shop manual shows dust seal and I am not sure what to order. Reading tech articles has me to understand 81 washers are longer. There are several different washers, seat, and seals in there. Is it possible oil contamination the real culprit, making clutch plates slip and brushes lose contact?

Andy, so far the only part not available from Honda is the thrust washer (P/N 90466-422-000). Try Service Honda - they can get you a better price. Was the oil you found actually IN the Alternator or in the area where the alternator mounts. If in the alternator, you will have to

dis-assemble the rotor and pull it out to get at the seal

(P/N 91216-PA0-003). There is no doubt that oil within the Alternator can cause a lot of problems. Wipe it off the rotor and measure the resistance through the rotor winding (do not measure in the carbon brush track but on the unworn part). A good rotor should measure about 4 ohms, not less than 3.5 ohms and not more than 5.0 ohms. You can't measure the Stator winding very accurately, there is another way to test that. After you replace the seal and NEW brushes, try it in the bike to see if you are OK.

The plates are designed to slip under acceleration and they are oiled so oil in the plate area is not a problem. A brand new spring will measure about 1-3/16", so unless it is substantially less, it is probably not 'set' but they can loose tension so keep it in mind.