Alternator Trouble?

[GSXR]

Hi,

ST1100L 1990 UK

Hope someone can throw some light on this for me.

Only had the ST a few weeks. Started the it this morning with no problem. Went inside to get my gear on and tried to retstart. The starter turned mementarily and then nothing. No lights, horn, dashboard lights, nothing. Turning the keyy to "Off" brings the clock to life, turning it back to "Run/On" puts it off again.

I then used leads to jump start the bike and it started very easily - no hesitation and ran fine. Disconnected the leads from the bike and it continued to run fine. Turned on the headlights and it killed it. Dead. No gradual petering out just killed it dead.

I suspect the alternator at this point. Any advice?

I've loved riding it so far and really want to get out on it again soon!

Thanks in advance,

Ian.

 

[Hound]

Alternator may be toast, but could be duff battery or dead regulator/rectifier...

 

[Avtrician]

Conect a multimeter to the battery, and measure the voltage with the engine running, if the voltage is below 12 Volts then there is a powersupply problem of some sort. As previously mentioned, a regulator or alternator (or Both). May even be a dropped diode or two in the rectifier. Evidence of this is dropping output voltage with increasing load..

Section 17 of the maintenance manual has the details. It can be found on the net if you dont have one.

 

[GSXR]

Thanks for the quick replies.

Alternator may be toast, but could be duff battery or dead regulator/rectifier...

Excuse my ignorance but is the regulator/rectifier one unit? I have a flat black unit between the battery and (I think) the starter relay, connected with approx 7 pin multlpug. Is that what I'm looking at?

Any ideas as to what would cause the batery to discharge so rapidly after starting the bike first time and then not even enough power to run the dash lights only 10 minutes later?

Conect a multimeter to the battery, and measure the voltage with the engine running, if the voltage is below 12 Volts then there is a powersupply problem of some sort. As previously mentioned, a regulator or alternator (or Both). May even be a dropped diode or two in the rectifier. Evidence of this is dropping output voltage with increasing load..

I've added a multimeter to my shopping list...

Thanks again for your time guys.

Ian.

 

[Hound]

Yes, the bit you're looking at is the VRR.

Batteries can die suddenly. It may, for example, have developed one cell with inverted polarity. That would certainly kill it. It would appear to charge, but not hold it.

It does sound like the alternator is the likely suspect, but it's better to eliminate the battery first - much easier access and cheaper!

Also, double-check the fuses shown in the circuit for corrosion.

 

[GSXR]

Here's the latest. I removed the battery and hooked it up to my Accugard and it went immediately to fully charged/maintenance mode, meaning the battery won't charge or won't hold a charge.

I checked the 6 or 7 fuses in the main box and checked the 30 amp fues in the starter relay. All were very slightly corroded/oxidised, would a dose of WD40 be the way forward there?

I'll order a new battery tomorrow but is there a chance that a faulty VRR or alternator could have caused the battery failure? If so, can I check anything once started to identify and rectify (no pun intended!), a fault before toasting another battery?

I'm learning a lot here, hope I'll be able to pay-back one day!

Cheers,

Ian

 

[panman]

Hopefully your battery had just reached the end of its life so to speak,As mentioned the best guide is the voltmeter connected to the battery while the engine is running,Voltage should be about 13.8 volts,Let us know how you get on,Nick.

 

[scout]

I had the same problem and was concerned about the altenator. I replaced the battery and everything was fine. I would recommend a new battery (can never hurt to have a fresh battery) then use the multi-meter and see how the voltage reads. If it jumps up and down from 14 to 12, then your altenator is having issues. The 28amp altenator is problematic and upgrading to the 40amp altenator that came with the post 1996 models is frequently suggested as a good idea. I am upgrading in the Fall. Good Luck figuring out your issue.

 

[Hound]

In the UK, the 40A alternator is actually more problematic than the 28A, due to it being air-cooled rather than oil-cooled. With salt in the atmosphere (we're an island!) and a lot of salt on the roads, the inner parts of the alternator - vulnerable due to the slots in the casing - corrode and seize up. The oil-cooled 28A version does fine as long as it isn't asked to handle too many extra accessories, and even then it can cope pretty well as long as the VRR is upgraded, like on the police models.

 

[sirepair]

Make sure to check the connections to the regulator. There are often poor, corroded, hot connections between the alternator and regulator causing charging issues. Many have cut out this connector and simply soldered the wires to the VRR to prevent this problem.

 

[Mark]

Hope it is just the battery...

Answer to one of your questions: I wouldn't use wd40 on those connectors; buy some dielectric grease and use it after you clean the corrosion. This grease will protect those pieces from the elements.

 

[GSXR]

Thanks for all the answers so far - I'm getting more optimistic about the outcome now.

I suspect now that someone has added some hugely powerful headlight bulbs to the bike (something like 100/80w). This isn't going to help my situation, right?

I have ordered a new battery and a multimeter (get both tomorrow), but I think I'll order some new headlamp bulbs to put my mind at rest.

I've read and re-read my Owners Manual and nowhere can I find the spec of the bulbs. From Google it seems that they are H4 but not really H4 and that they are 45/45w? Can anyone verify this? I don't normally ride at night but I do use the lights in daytime running so massively powerful lights are more a hinderance than a benefit to me I guess.

Thanks again,

Ian

 

[panman]

Hi Ian,Copy and paste this number 160322148575 Into flea bay and bingo one pair of standard H4 55W bulbs for your ST ,Nick. The buy it now is ?6.99,Just offer them a Fiver you should get them ok

 

[GSXR]

Thanks for taking the time to search ebay for me Nick.

If they are normal 60w/55w H4 bulbs I have a couple as spares for my cars but I keep reading about having to cut off two of the tangs and using adapter shims? Am I reading the wrong stuff again??

 

[alphafang]

Ian the adaption to the H4 bulbs are made by our American cousins they run different bulbs, You will be fine with standard H4's.

 

[Hound]

Yep, they are the standard 60/55W H4s, and you won't need to add shims or cut off tabs or anything weird. Just bung 'em in. You may find a mirror or an old CD useful so you can see what you're doing with the wire clip when removing and fitting the bulbs.

I'm not sure whether the wiring could cope with 100/80W bulbs for an extended period, and they might even melt the headlight reflector given time.

 

[ligito]

I have Battery Tender Plus charger and an old 2 amp charger.

My friends battery would not charge on his, or my Battery Tender, but I was able to bring it back to life by charging it on the old charger, then It was able to be charged again, on the Battery Tender.

If you have access to both type chargers, try the old trickle type/standard charger, before you give up on your battery, unless the battery is too old, or has been discharged too many times already.

 

[bdalameda]

+1 on the regulator connections. The three wires from the alternator to the regulator/ rectifier are known issues. It is very possible to have one winding not connecting and this will give you only about 11.5 to 12 volts output - just enough to barely run but not enough to pickup the battery if it is low or run any lighting. If you continue to run with one winding not connected eventually it will cause a failure of the alternator and regulator/ rectifier. If you are lucky you may catch it before this happens. Look for any overheated connectors or wire.

 

[GSXR]

+1 on the regulator connections. The three wires from the alternator to the regulator/ rectifier are known issues. It is very possible to have one winding not connecting and this will give you only about 11.5 to 12 volts output - just enough to barely run but not enough to pickup the battery if it is low or run any lighting. If you continue to run with one winding not connected eventually it will cause a failure of the alternator and regulator/ rectifier. If you are lucky you may catch it before this happens. Look for any overheated connectors or wire.

I take it that these are the three yellow wires (but I guess checking/cleaning all of them is a good idea). Anyone have any tips for cleaning the socket (female) side of these spade type connectors? Do I just get a small screwdriver in there and scrape away whatever crud I can? Is there a spray that 'eats' the copper oxide? Could I use vinegar like cleaning old pennies when I was a kid?

My plan for tomorrow or Wednesday is to take a Volt reading from the new battery. Connect the (-) side of the new battery and connect my meter in line with the (+) lead and take an Amp reading with the ignition off (to check for a short). Fully connect the battery and start the bike. Take a Volt reading at idle and at say 4000 rpm. Switch on the lights and repeat. Does this seem like right method?

God I feel stupid asking all these dumb questions - I just hope next time my computer breaks instead of my bike - I might stand a chance with that!

Cheers,

Ian

 

[bdalameda]

Yes the three yellow wires are from the three windings of the alternator. These are the ones that can have connection problems. To check the alternator windings disconnect all three of these wires. Set your multimeter to AC current and start your engine with these wires disconnected. Check power between any of these wires and any two wires should have voltage output typically from 50 to 80 volts ac depending on the rpm. I don't remember the voltage/rpm output but that is not too important. Any two wires should check with ac current and be at the same level regardless of which two wires you check. If you find any two wire combinations with no voltage or much lower output this indicates that you have a bad winding in your alternator. If the windings check out okay and with everything re-connected you should have around 13 to 13.8 volts DC at your battery with your engine around 4500 rpm. If you still do not have this voltage it indicates your regulator rectifier is bad.

Dan