Alternator warning signals?

[Paul Carver]

Are there any signs, signals or noises that one can gauge the "goodness" of their alternator with? I have 109,000 miles on the bike and am preparing for a 8,000 mile, 28 day trip this summer and this just has me concerned. Is changing the brushes enough? Thanks for your help.

[Chrisj CMA]

I have 110K miles on my Valk....original alternator.....every 40-50K miles I have cracked it open and blew out the dust, checked the bearing and replaced the brushes once.  Thats all I know to do, but still I installed a volt meter so I can monitor how much the dang thing is putting out.  I dont think they necesarily give any warning unless its the bearing thats going south, then you may hear a squeal or something.  You are at the mileage that no matter how well you cared for that alternator it could go, me too.....I wouldnt leave home without a volt meter running so I knew the dang thing was crapping out before the engine just dies for no apparant reason.  I also have a new alternator that I carry with me on long trips.  They dont last forever and over 110K is more than some get

[Ricky-D]

An easy way would be to use a volt/ohm meter and measure the voltage at the battery with the motor running.

Somewhere around a high idle you should be seeing 13.5 to 14.5 volts.

13 volts or less indicates a problem in the charging system.

Of course this needs to be done with a good strong battery that's fully charged.

***

[fudgie]

Wouldn't hurt to take it out and have it checked by a alt place.

Where ya going?

[Jess from VA]

I think pulling it as a preventive is overkill.  I believe the majority of valk alt failures are directly related to a bad batch of windings (though this has never been clearly related to any make-model-year group).  Most who lose one do so in the 40-60K zone, and if you are well past that, you may never have a failure.  I suppose another reason is poorly added multi electricals overloading the system.  I have the Kuryakyn voltmeter (black) mounted up on the inside fairing, and have made a habit of keeping my eye on it (esp at startup and while sitting at long lights idling).  I run battery tenders 24 X 7 year-round when off the bike, so my batteries are always in perfect charge.  I found it bothersome that the leds in the Kury gauge go to green at dead center, but never ever go above that but, as far as I know, all is well.

[3W-lonerider]

windings can fail at anytime..my windings failed at 126,000 miles. as far as a warning..the last couple of weeks before it failed..i took notice that my altenator would only charge at 13.8 volts..when it normally would charge at 14.1.

[Friagabi]

The most common failure due to a bad altenator is a thrown winding from the rotor. One of the winding ends hooks to one slip ring and the other end hooks to the other slip ring. A good motor shop can tie down the wires so they do not come lose and break off.

Having said that, long running hours cause failures of the brushes They just plain wear out. While doing so they leave powered brush material in the alternator. This stuff conducts electricity being collected there can cause short life of the regulator and other components that do not expect to be covered in powered material that conducts electricity. The next failure would be the bearings from long running hours. Past these then a new alternator has failures just as would a old alternator.

Good advise is to check the length of the brushes and blow out the dust. While in here look to see if the winding ends are tied down.

For those who do not know, Tieing down the ends of the windings is as follows. On the shaft of the rotor, just between the slip rings and the windings proper the ends of the windings are laid on the shaft leading to the slip rings. In this area high speed spinning causes the wire to throw off the shaft. This stress can cause the wire to break and that is complete failure of output to charge the battery. Sometimes the wire is covered by tape and then dipped in sealer. The correct way to do high speed shafts is to wrap the shaft of the rotor in this area with cotton string. Fishermen will understand this, same process used to put eyes on a fishing pole. Then soak the string in epoxie, slow drying so the string becomes completely soaked and then will support the wires from comming lose. Generally the soldered ends of the wires are also covered as will be the slip rings. But if you go this far then the rotor will have to go into a lathe and have the covering machined off the surface of he slip rings. If the windings in the rotor are wound tight then this is generally a "failure proof rotor". If you were to hand wind the rotor then each layer of the windings are covered with a heat-set sealer. When finished the rotor is baked in a oven The winding then become even better insulated and never will they rub against each other and fail.