Alternator bad or?

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daves79x
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Re: Alternator bad or?

Post by daves79x »

Dynamohum - a couple of very nice folks have explained, far better than I can, where I'm 'coming from'. I'm sorry if this is confounding to you. I offered my advice even to the point of offering my phone number to talk in person. You asked for help and I offered. Whether you chose to act upon that was totally up to you.

You seem to think that the alternator is some magical device that can't be worked on. It in fact, is one of the most straightforward systems on the CBX. As I said before, you are indeed a most fortunate long-time CBX owner that hasn't had to delve into the alternator several times. But I assume you have a good CBX mechanic to look after these things. My advice is to please have the alternator evaluated if you aren't comfortable doing it yourself, before you spend loads of money on a replacement.

Good luck and sorry again that we got off on the wrong foot.

Dave

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Re: Alternator bad or?

Post by Larry Zimmer »

And, besides what Dave mentioned about the alternator itself, check ALL connections in the charging circuit for any little sign of corrosion. After 40 years, all old things collect some in their joints. Even if not abused. (Ask me about it some time. Some of my joints/connections are a fair bit older than that!) But, seriously, the least corrosion in those connectors will markedly diminish charging. But, be certain to check, or have checked, the alternator as Dave said.
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Re: Alternator bad or?

Post by Dynamohum »

Everything inside the alternator cover and it’s connections tested ok except for the stator. As I mentioned, the charging system had always worked well and the battery turned out to be ok. Once charged up the bike fired up as usual, just not charging. In 2002 I believe, when I first swapped out the brushes, I changed the coupling (clutch) plates because the oil journals were gone, they were just flat worn out looking discs. Now they look grooved like tiny scored brake rotors. How did that happen I wonder? There’s no metal floating around in there. The originals in 02 were just worn out but completely smooth. Replacement costs are sky high for used ones and new ones are in outer space. Will I be able to replace the stator working alone w/o a vise?

Thanks to all for the advice and direction.

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Re: Alternator bad or?

Post by daves79x »

Thanks for reporting back. Please clarify if you mean the rotor (the heavy round thing) or the stator that tests bad. Could be either, but usually it's the rotor. You need a press to change the rotor, and an air wrench to buzz off the remaining nut. The stator is easy, just unplug and unbolt.

This is this the low-down on the clutches, and everything mentioned next is important. First, the clutches were designed to 'slip' - that's the point of having a clutch. This naturally leads to some wear. Grooving is very normal. Signs of excessive heat, crystallized oil is not. Honda designed the system, so that if everything is up to spec, for the clutches to last at least 100,000 miles. My nearly 50,000 mile '79's clutches will easily do that (but not by me). So what can go wrong? Lots.

First, a bearing can fail in the alternator, causing excessive drag on the clutches, allowing them to slip and grind each other more than normal. Second, oil flow somehow gets reduced to the alternator (through the 2mm hole in the plug at the end of the primary shaft). Third, really abusing the engine, drag racing, etc (which is fine by me, but just know the consequences), can heat the clutches excessively, causing the spring to overheat and sag and the plates to turn blue from the heat. A new spring measures 31mm. Anything less than that need shimmed the appropriate amount, plus some extra for clutch wear. Any spring measuring less than 29mm should be replaced.

The clutches are manufactured slightly concave (Honda screw-up, or not, who knows), so that you don't get full contact area. Figure eighting them on a pane of glass with 80, then 120 grit emery paper until flat should be done. Ensure the primary shaft plug hole is open. Then evaluate the spring and replace as required. Shim with extra steel washers as explained above. Ensure you have both stock washers - the thick fiber washer and the thinner steel one.

You don't see metal particles because everything the clutch sheds get dropped directly into the sump through the huge opening directly below them. Drop your sump cover (you should have done this several times by now anyway). You will see fine metallic sludge in the bottom.

Now to the alternator itself - once you replace whichever component is bad, replace also both bearings and the center seal, and shaft o-ring, unless you know for sure they were replaced recently.

Set up this way, your alternator will prove quite reliable, as yours has the last 70,000 miles. But you must check ALL the above - do not shortcut anything or you'll be back into it soon.

If you can flatten your plates, don't worry about remaining grooves, as long as there are still some of the oil grooves left. The spring and clutch plates are long NLA from Honda, but Louis still has them, as far as I know. As far a price, I can only say, review my earlier post on this thread about owning a vintage bike.

Dave

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Re: Alternator bad or?

Post by Dynamohum »

Thanks Dave. I’ll clean up the clutch plates and of course everything else. I priced some OEMs and ‘used but good’ ones and both are outrageously priced I’m sure, due to their scarcity. I called the mechanic who tested everything in NV to confirm that’s it’s the stator not the rotor. I’ll get one and have a go. It’s the perfect bike to ride the nearby Sierra passes and foothill two lanes.

Stator, number 3 here,
https://www.powersportspartshack.com/oe ... alternator

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Re: Alternator bad or?

Post by daves79x »

Stator tests are not as definitive as the rotor test. And if your guy did not have a late model shop manual, which is the only one that gives an OHM value for the rotor, I have no idea how he would know if the rotor was good or not. I’d personally get a definitive evaluation of the stator and rotor by a CBX guy before I spent any money.

Dave

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Re: Alternator bad or?

Post by Dynamohum »

FIXED (I hope) :D Took two tries as the old brittle brush plate cracked in pieces after the install (I may have over tightened it). :-| Installed the new/old but better stator and it charged for awhile and then made a loud scraping noise and stopped charging. Removed it again and saw the broken pieces including a broken brush. Luckily I had a spare set of brushes and a brush plate. Reassembled everything, started it up and voila, it’s charging! :clap: I’ll take it for a proper test ride mañana. Thanks again for all the help. :text-thankyouyellow:

daves79x
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Re: Alternator bad or?

Post by daves79x »

So glad you got it fixed! So it was the stator after all?

Dave

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Re: Alternator bad or?

Post by Dynamohum »

Yep, stator. Went for a nice ride and it’s charging just as before, right above 13 on the gauge. Now I’m wondering if I should take advantage of the current prices for one and sell it before it requires a valve job etc etc. I’ve put over 40,000 miles on it thru seven states and it now has just over 65,000 and has never been apart. It could use a good detailing but most wait until the motor has to come out to do that. Not sure I want to wait that long. I have two sets of pipes for it.
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daves79x
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Re: Alternator bad or?

Post by daves79x »

I’ve got a friend’s ‘79 here right now for some service. It has nearly 90,000 miles, many of them very hard, and it still runs very well. It does use a quart of oil every 800 miles or so, but it performs and sounds great. I don’t imagine your bike would be worth significantly less at 75K or 85K. I’d run it as long as it stayed dependable and ran well.

Dave

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Re: Alternator bad or?

Post by desertrefugee »

Sheesh. Makes me feel pretty good about my 22k mile specimen. I didn't realize these things were so long legged.
'86 VMax, ‘83 ZN1300-6, ‘78 GL1000, '75 750K

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Re: Alternator bad or?

Post by Dynamohum »

I think my 82 had 106,000 on it when it sold. Great touring mount. Probably still running around somewhere. Amsoil is good stuff!

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