Dead Short blowing 30 amp fuse off battery

[zippyskippyCBX]

Guys, I need your expert help here already

I just finished installing my new Dyna ignition system yesterday and was heading out this morning for a shakedown cruise. Get a mile from home and everything just goes dead. Pulled the right side cover and there is the 30amp smart fuse glowing red as it has blown. Get the bike home and start by rechecking the wiring I did for the ignition, the wiring I did for the Koso RX-w instrument cluster, nothing obvious. I then unplugged every connector on the bike, including all the ones in the headlamp bucket, trying to isolate where the dead short might be, and then put a new fuse in and start plugging connectors back together. Nothing blew the fuse, until I got to the rectifier plug. The rectifier was still unplugged from the alternator, and as soon as I plugged in the red connector for the rectifier by the battery box, the fuse instantly blew. Am I safe in assuming that I have a dead short within the rectifier/regulator unit ? If that is the case, is there any thing else I need to look at that might have caused that problem, or is it just an age thing with these rectifiers ? I appreciate all of your help as I know the answer lies within your vast amount of knowledge.

Scott

[NobleHops]

Scott, did you also do the Dyna coils?

If your problem is not in the R/R itself then it is in the black/white wire - the ignition leg of the bike. If you did run Dyna ignition and coils than I am guessing you brought power up to the coils (and hence the ignition) from that red connector.

Me and at least one other human being made the same mistake wiring the Dyna coils that could be the culprit - it kicked my a** for a while. On the left side coil, if you mount the ring connector in a vertical orientation, it can and will ground the hot leg of the coil circuit to the bottom of the gas tank, and POP goes your main fuse. If you did mount the ring connector on the new coil in a vertical orientation, look very closely at the underside of your tank and see if you see some scratching 10 inches or so back from the front edge. And if your intellectually BRILLIANT brother or some equivalent person suggests that your woes might be simply cured by installing a higher amperage fuse, poke his or her eyes out and ignore them, as I should have. <coughNEWWIRINGHARNESScough>

Pay close attention to the routing of that wire as well. Theoretically speaking, if a person is careless, it is possible to crush that wire when you tighten up the airbox (SPEAKING PURELY THEORETICALLY HERE).

Search the electrical forum for more threads on the Dyna subject and you will find more wisdom. Last thought - consider bypassing that stock main fuse and installing an inline modern fuse holder, if you haven't already.

N.

[zippyskippyCBX]

Nils,

Nils,

Nothing like the voice of experience, eh ? My bike already had the Dyna coils installed, it just was missing the rest of the Dyna system. That leg, the black/white power feed and wiring to the coils, was the FIRST thing I checked, as I had changed the spade connectors at the coils to ring type terminals just to make sure I had great connections. I did not bring power to the coils off the "Red" connector, which is a four wire connector by the way, and is the one that runs directly to the rectifier/regulator unit. My bike has the black/white wire coming off the "Brown" connector, which is just a two wire connector.

And yes, I do already have a modern inline fuse holder that comes off the starter solenoid and runs into the main wiring harness. That is the fuse that is blowing, not the main one at the handlebars. I had installed a "Smart Fuse" in this holder, that glows red when it is blown. As I don't usually have my "reading" glasses with me when I ride, it sure made it a whole lot easier to see why I had no juice anywhere as soon as I popped off the right side cover. Thanks for sharing your "experience"............Bigger fuse.........yeah, that'll cure it, OMG......I am LMAO, seriously.

[daves79x]

Scott:
Did you have the alternator off at any time during this last round of work on your bike? The black and the white wires in the connector to the alternator are the 12v feed to the brushes. With the bike not running, that is the only thing 'hot' when you plug in the connector. I'd check to see if you don't have a ground in the brush holder or the wires to them in the alternator. Sometimes the holder screws can pinch one of the wires. It has to be in that 12v circuit.

About your 12v to the coils - I'm working on a friend's '80 CBX right now that had a butchered wiring job done while someone installed the Dyna coils and ignition. After sorting it out, I peeled the black/white wire from the stock coil feed, installed the feed end into a spare brown male connector (or just take the brown one from your now-removed stock spark unit) to match the stock female brown one still on the bike. I then just plugged them together and had a stock-looking feed to the new coils. However you connected that black/white wire to the brown connector, just make sure it is not touching the green wire that is in the connector also.

Dave

[zippyskippyCBX]

Hi Dave,

I have not had even the cover off of the alternator up to this point. The odd thing is that I had the connector from the rectifier/regulator to the alternator UNPLUGGED and when I connect the other lead from the rectifier/regulator to the main harness, it blows the fuse. That leads me to think that the rectifier unit has a dead short in it, but I am definately not a wiring genius (or any other kind for that matter, lol). EVERY other connector on the bike was unplugged.

As far as the coil wiring goes, like you said, I reused the stock brown connector and the stock fused together side by side 4 wire flat coil wiring loom that goes to the coils. I took Nils story to heart, and rechecked the wiring to the coils. I then discovered that whoever had originally installed the Dyna coils had wired the "hots" on the bottom terminals and the "triggers" on the top terminals (it ran that way though). So I changed those to the way they should be wired with the "hots" on the top, taking care to ensure they couldn't ground accidentally to the tank with careful placement and shrink wrap on the terminals. Today, I hooked up all of the connectors again, EXCEPT for the two rectifier plugs. Power to everything and the bike started and ran just fine. I did find a thread on this site somewhere with a link to Mike Nixon's site. He says there that if the field coil (rotor) in the alternator has a short in it, due to poor design, heat, etc. that it will almost always take out the rectifier/regulator as well. Could I be chasing an alternator problem that in turn took out the rectifier as well ???

If that is the case, wouldn't I just be better off to buy one of Tim's CBX alternator conversion kits and eliminate the rectifier/regulator and the clutch in the alternator, and have something that charges at all RPM's ??? Has anyone had any problems with this conversion kit ???

Oh to have a CBX I could actually ride...........................

Scott

[Terry]

In re: "Has anyone had any problems with this conversion kit ???"

None that I've heard of except possibly it getting wet while riding in the rain, but the one thing that keeps me away from it is the price and its real necessity. Its designed for those who fire up their Xs 5-6 times a year. Once the OEM system is in good working order (and) its ridden frequently the OEM stuff works very well. Proof of that is in my two Xs for example, over 50,000 miles on the 79 and just under 100,000 miles on the 82. All I've had to do is change the alternator clutch plates on the 79 and brushes on both...oh yeah, and put a lot of miles on them! Good luck with your electrical demon. :twisted:

[steve murdoch icoa #5322]

If you decide to go with an alt. conversion kit, J.R. a poster here makes an excllent product.
In six years of use i have had zero problems.
viewtopic.php?f=5&t=5663&p=41234&hilit= ... kit#p41234

[daves79x]

Scott:
I read your account incorrectly. With the alternator unplugged, you are just picking up the hot lead directly from the battery when you plug in the regulator. Sounds like you are correct - something is shorted in the regulator, although seems too much of a coincidence that you would develop that problem while you were working on the wiring elsewhere. Anyway, as Terry said, the stock charging system, while a bit maintenance-intensive (compared to the rest of the bike) works just fine for thousands of miles. The most common failure except for brushes, is the rotor. The rotor test in the manual is definitive, the stator test may or may not be, but do them both. Check the output of the alternator (unrectified AC) with the bike running and the unit unplugged. If all is well there, then I'd replace the regulator and you should be good. It'd obviously be nice to have a spare one right now to try and see if a known good one blows the fuse.

The clutch plates and spring are sometimes an issue if they've gotten hot, but usually last a long time if everything is good to start with. Sadly the OEM spring is NLA from Honda here in the US - it may be available elsewhere, I haven't checked.

Dave

[zippyskippyCBX]

Dave,

I also firmly do not believe in coincidences, lol, but this one has me stumped. I am in my shop manual in Section 16 and I do not see any "definitive" test for the rotor. 16-7 does however list the "Stator Coil Continuity Test". I performed that one and it checks out OK. Where could I find the proper test for the rotor ??? I wonder why it is not in my Service Manual..............

thanks, Scott

[daves79x]

Scott:
Sorry, I should have asked if you had an early model service manual - it does not list the continuity value for the rotor. The late model manual does and you have to measure between 3.5 and 4.8 OHM between the slip rings. Any high or lower and the rotor needs rewound. Most good rotors measure between 4 and 4.5 OHM. That is the only test of the rotor and it is absolute. The stator tests are clear enough, but you can test a stator to be good by the book and it still is faulty, but in any case a stator failure is rare compared to rotor failures.

Service on an otherwise good alternator (good rotor and stator), involves brushes, bearings and seal, plate condition and spring condition. If all those parts are good, serviceable parts, and all connections are clean and tight, they will go thousands of miles, as Terry said, with no trouble. But, the aftermarket conversions are really nice and trouble-free, if you want spend a few bucks.

Mike N. is a better reference about the issues a failure in the alternator can have with the regulator. I've not experienced any catastrophic failures in that regard.

Dave

[zippyskippyCBX]

Alright Dave,

Now we are getting to the nitty gritty. I pulled the alternator off, took it apart, and tested the slip rings on the rotor. I have a measurement of 4.1 ohms, so that part looks like it is still good. I think that only leaves the rectifier/regulator unit as far as the dead short, no ?

Now on to the rub...........looking at Section 16-0 in the Service Manual, there is a blown up diagram of the alternator. Starting at the engine side, the spring seat was there, the spring was there, THE THRUST WASHER WAS MISSING, THE PLAIN WASHER WAS MISSING, both halves of the clutch were there, and the O-RING WAS MISSING. I don't like how both halves of the clutch look, they are both scored, so shouldn't I replace the clutch while I am in there ? Wouldn't the missing washer and thrust washer make the clutch slip more due to less pressure from the spring ??? I will also replace the brushes while I am in there as they were half worn to the scribe line. I know the rectifier is available at Tim's but I don't know about the rest. I guess I will start at my Honda dealer. Any recommendations for parts ?

I am thinking my parts list should look like this; Rectifier/Regulator; Alternator Clutch (does this come as a set with both halves?); Thrust Washer; Plain Washer; Brush Set; large O-Ring.

Can't thank you enough for your continuing help. Cheers, Scott

[EMS]

Scott: Be practical and check and add up the cost for all the repair parts you need and then compare that with an alternator conversion from JR.
You may be better off using this. I did not have serious problems with the standard alternators on any of my CBXes and have replaced them all with alternator conversions.
Granted, I did it when they were still $425.- from Stefan Jung, but it still may be the more economic way to go, especially if you need a new regulator/rectifier which will no longer be needed with the conversion.

[daves79x]

Scott:
It seems you are going to need some parts for your alternator, several of which are no longer available from Honda. I'd get a new spring, but they just became discontinued. I'm in the process of checking with David Silver in GB to see if they still have them. I have a couple of new ones here, but am reluctant to sell them. They are only like $11, but you can't order one. Louis, I suspect, has several new ones, he may have even snatched up the remaining American Honda stock when they got low enough (this info is easy to obtain from a dealer friendly enough to look). But I'll be they are not $11 any more! Anyway, the steel washer has been NLA for years, but a suitable substitute can be sourced locally. The thicker fiber washer is special and may or may not be available yet. Are you sure they are not stuck to your drive plate? The plates would barely have any pressure on them with both washers missing. The plates themselves were available last time I checked - about $150 for both. Bearings and seals are about $20 from your local bearing supply.

So assuming you can buy the plates from Honda for $150, bearings for $20, and buy the spring and washers from Louis (they are not worth more than $25 retail, but are I suppose if you can't get them anywhere else), brushes from Honda (do not use aftermarket ones - they last about 5000 miles) for $50, gasket from Honda for less than $10, you still have less then 1/2 the cost of the replacement alternator (oops - forgot the regulator - $100 more or less).

If you knew for sure the short was in the regulator, then your decision would be easy - chuck the whole thing and buy the replacement (a very attractive option) or source all the new parts you need and put the stock stuff back into service. It would be nice if someone locally to you would loan you a spare good regulator just to try plugging in and see if the fuse holds. Any Honda regulator of the era with the same plugs will work for that. Actually, you could plug in a known bad regulator (one that didn't have a short in it, anyway) and test that. I have a couple of early model bad ones, that don't blow fuses, that I could send you to try.

Think about what you'd want to do knowing the options and let us know.

Dave

[NobleHops]

Scott: I have a nearly-new R/R that I can have in the mail to you tomorrow. It was installed and run for about 5 minutes in total, and then de-installed. So it is known to be good. If you would like it for testing purposes at least, I'll send it. If it turns out you need it, we'll figure out the going rate and you can keep it.

PM me your address if you want to do that and it'll be on the way, but if you don't tell me today, I won't be able to mail it till next week.

obFreeAdvice, given what you might be looking at for alternator repairs plus a new R/R, I'd personally be on the phone to J.R. by now, but that may not be consistent with your ambitions for the bike, nor your finances.

Question for Dave though: Dave, if his plates are not blued and showing signs of overheating, couldn't he just lap them and shim the spring with an extra washer, chamfering the groove edges?

[zippyskippyCBX]

All right Guys,

Message received !!! I called around: Tim's had the missing washers (used), the rectifier (new), the missing o-ring (new); Louis had couplers A and B (new) $250 for those gems NLA from Honda (ouch), brushes from Honda (new), etc. EMS, you are a man after my own heart. When you add it all up with freight, I would be in $450 for parts and end up with a funtioning original equipment charging system, along with all of it's faults. For a couple more C-notes, I will have the Kawasaki conversion unit (it will be here Wednesday) and the end of these and potential future issues. As this bike is far from stock and I am not a purist, it was a no-brainer really. Don't you just love fixed PO's mistakes ???? I am getting a little worn out from them actually, and my checkbook has now gone from smoking to a full blaze !!!

Therefore, I do have a functioning alternator with brushe
s at 50% or more, a good rotor and stator, and a beautiful chrome cover available if anyone is in need. I really hate having any parts laying around that know I will not use. It's that clutter thing, lol.

Thanks again for all of your insight and suggestions. I really appreciate it. By the way, I did join the ICOA yesterday. Any ideas on how long it takes to start getting the magazine ???

Scott