Alternator Failure Symptoms

[mojosaan]

A few weeks back I had a fuse that kept on blowing (4A fuse to the instrument panel). Took it to the dealer and they said it was because of tight zip ties and loose connection to instrument panel. Okay, the fix from the dealer lasted a week and the fuse blew again. Except now, I noticed that the tach doesn't fluctuate as it did before, it stays zero and the Battery Charge Current Light is always on, no more revving and the light goes away situation, it just stays lighted no matter the revvs. After reading a lot of posts here, I bought some new 4A fused at $1.25 each , cut some zip ties and new the fuse blows immediately after it started and the light is consistently on and the tach doesn't work. This leads me to believe that the alternator is broke. I also checked the poly v belt and that is at spec, so again, I believe it is the alternator. So, I used a multimeter and the voltage from the battery is 12.36 while the bike is off. Once the bike is started and idling with the choke on, it goes up to 16, which seems like it is charging but in one of the postings on here someone said the voltage should not go over 15, which mine clearly does.

So, what's the right reading I should be getting from the battery when the bike is idling with the choke on? The manual shop manual says that the alternator should be putting out 18 at 4000 rpm, so why should a reading of 16 at idle be a problem? I am all confused as to what can be causing this problem that seems to be getting worse. Might ths problem be one of the relay's is broken? Once again, any comments and suggestions is much appreciated!

[boxermania]

mojosaan

Fuses usually blow because there is an amp draw on the wire above design parameters. Tight zip ties, especially those on the right side down tube by the tank, have been known to lead to broken/shorted wires and that is probably what you are experiencing. Locate a wiring diagram, so you can identify the wire color in question, if not, pull the fuse box and look at the wire leaving the fuse (cold side)as that is probably the one being shorted out.

Since you have already have a DVM, I suggest that you remove the blown fuse. Establish which side of the fuse holder is the hot side (12V) and then measure resistance from the other side of the fuse holder to ground. You’ll see that it is shorted.....or in other words meaning the same thing, showing continuity to ground......

In regards to the alternator and the voltage at the battery, there is something apparently wrong as with the bike running at ~2000 rpm the alternator output should be regulated to about 14 VDC, as anything higher is detrimental to the battery. I would have to ask where you are measuring the voltage.....

The alternator can go bad basically for two reasons, 1) The bearings go bad (rarely) and 2) The voltage regulator goes bad and either charges too little or too much, neither good.

I think you have enough to go chase.....locate the sorted wire(s) and correct those before proceeding......to the alternator.

Let us know how you make out.......

[mojosaan]

Thanks for the suggestions. I measured the voltage from the battery terminals when it was off and idling on choke. Also, I am not very familiar with electrical stuff so if I performed what you suggested, then what would that show me? That there's something wrong with the wiring and not the alternator? Also, if it eventually leads me to the alternator, is it possible to change the voltage regulator? How would I check to see if the regulator is broke and not the alternator itself? Thanks again!

[boxermania]

mojosaan

I'm not outwardly ruling out the alternator as potentially one problem might cascade into the next.

Looking for the short and correcting it would be the first thing, and then let's see how the alternator behaves. If the alternator and or voltage regulator are indeed bad, you will have to replace the alternator as the voltage regulator is an integral part of the alternator.

Being that your have limited electrical skills, I would recommend that you seek help. I don't know where you make home, but there might be another member of this forum that has experienced the "short" malady, lives close by and could volunteer his help.

As before, good luck.......

[maduko]

mojosaanEstablish which side of the fuse holder is the hot side (12V) and then measure resistance from the other side of the fuse holder to ground. You’ll see that it is shorted....

Shorted or connected to a light bulb. You'll get continuity (0 ohms) either way.

The wiring loom near the steering head is a known issue and the dealer indicated a problem in that area. I would start up front.

The tacho and gen light wires probably go through the same loom from the instrument cluster. That's probably where your problem is.

[mojosaan]

Thanks again to all. I have a Clymer on order and hope to get to the bottom of this. I will seek some help. Thanks again, and I will let you know the outcome.

[CycleRob]

It sounds like you may (or may not) still have a short in the wire harness. If the alternator charge light wire to the bulb shorts to a wire with 12V power, illuminating the charge light, it may cause the regulator to malfunction - - - giving you 16V. I said or may not still have a short in the wire harness because the regulator could also have been damaged before the short was fixed.

Make the easy shots first. You need to cut apart the instrument wire harness where the short supposedly occurred and see what might be wrong. Crushed wires, overheated wires, wires pulled out of the connector, etc. Also cut and peel back the main wire harness that may have been traumatized by the steering movement. After that checks out OK, then run the bike for a battery voltage test. If it's not 14.1 +/- .4, then there is a regulator problem.

Shorts or arcing-n-sparking can permanently damage the regulator's circuits. The regulator is not difficult to replace once you gain access to the rear of the alternator - - - the really tedious part of the job.

.

[mojosaan]

My bike is still under warranty so I brought it back to the dealer, informed them of the issues I'm still having anf keeping my fingers crossed. I'll let you know what they find.

[mojosaan]

Got a call from the dealer and they told me they found bad wiring going to the tail light. I found out there are two harnesses and the one going to the tail light is connected to the fuse at issue. Anyhow, it is being repaired under warranty and the harness is on order. So I will continue to sit on the sideline watching others ride .