40A alternator, does this sound like a bad RR or is the alternator toast.

[garethjv]

Finally got good enough weather and time to poke around the electrics of my Pan last weekend to see what could be causing the charging issues. Having removed enough covers to see the actual alternator, it seems there are 3 cracks in it . Before condemning the whole unit though (it never actually seized or showed any other symptoms) I decided to probe the battery with volt and ammeters. What I found was slightly surprising. Before taking these measurements, the battery was fully charged:
First of all, without the headlights on, the voltage across the battery terminals was:
@idle (~800RPM) 11.7V
2000RPM 13.5V
3000RPM 14.1V
With headlights on full, the voltage dropped:
800RPM: 11.37V
2000RPM 11.65V
3000RPM 11.75V
Unfortunately, the voltage on the rear terminal of the alternator was similar so I don't think it's a connection issue.
I next disconnected the 55A alternator fuse and connected an ammeter across the connections. This is what I found: With the ignition on and the engine not running, 2.74A flowed into the alternator. Is this the current to energize the stator coils? It seems rather large to me. Disconnecting the 10A alternator/starter circuit fuse and measuring the current through this circuit (ignition on, engine not running) showed just 0.25A flowing after the fuel pump cut out. I thought this would be the path for energizing the stator but maybe I misunderstood the wiring diagram.
After starting the engine, the current across the 55A fuse connections was:
idling 800RPM: 0.3A from alternator
2000RPM 6.8A
3000RPM 9.7A (with headlights turned on).

It seems pretty clear that the alternator is failing, but does this sound like the R-R or the alternator itself? I wondered if anyone could comment on the 2.7A current draw through the alternator with the engine off.
Also do I still need to pull the swingarm etc. to test the regulator etc. or are there any further checks that I could carry out to confirm if it's the R-R or the alternator itself at fault without removing anything.

Any help or advice would be appreciated.

Gareth

 

[Woonjas]

There is a test hole (Full Field test terminal F) in the cover of the alternator that you can insert a narrow screwdriver into to short with the cover, this by-passes the regulator and should crank up the output - running idle you should hear a change in the sound of the engine, as well as an increase in the output voltage and/or current if you notice lilttle or no change, the voltage regulator is toast, which is a fairly standard Denso part you can pickup at car parts stores for less than 30 bucks.

http://www.autoshop101.com/forms/alt_bwoh.pdf discusses an alternator of similar design as the one used in the ST11 -

 

[ST1100Y]

Checked the brushes?

Friend of mine had an unseen coolant leak (yep, the elbow story...) on his '96, which poured over/through this alternator...

 

[garethjv]

Thanks for the suggestions, I checked the voltage regulator using the screwdriver in hole method and nothing changed, so I guessed that meant the regulator wasn't restricting the field coil current so it wasn't to blame. I've now taken the alternator out of the bike after much struggling to squeeze it from the frame, before realising I needed to separate the bundle of wires at the side that were restricting access. Surprisingly, (to me) it seems the alternator is practically siezed and can only be rotated by gripping the drive with a pair of pliers! I'm surprised the thing generated any current at all!
I'm now in the process of attempting to dismantle the thing and split the case but it's proving tricky! I'm surprised that the alternator has gone bad like this, it looks in better condition than the one currently on sale on ebay for nearly ?200. http://www.ebay.co.uk/itm/Honda-ST1100-AW-98-PAN-EUROPEAN-ABS-alternator-40-amp-/251511151690?pt=UK_Motorcycle_Parts_13&hash=item3a8f3b9c4a
I think my only real option now is to buy a new one and I think the best value looks like getting one sent over from the US from Partzilla and paying import duty etc. I was wondering if anyone here had done this and had any tips or problems on going down this route.

Thanks again for any help.

Gareth

 

[Byron]

With cracks in the case it would be replaced if it were my bike. The cracks may have been caused if it did try and seize and the case gave way first. Battery should be reading 12.7 to 13.2 if fully charged. Here is some battery info.

 

[garethjv]

Thought I'd give an update. I ordered a new 40A alternator from Partzilla in the US for $404. With VAT, duty, parcel farce's handling fee and my credit card foreign currency fee it all came to a total of ?361.09. A nasty sting but I didn't really have an alternative as the second hand ones looked ropey over here and I've had past bad experiences buying used automotive electrical items like this. Still, it's cheaper than the non-genuine alternator that David Silver stocks (?510 inc vat and he's now out of stock) and it seems from the Honda labels on the box to be a genuine item. I've given it a good spray with ACF50 and will do the same again once I've mounted it to the bike.
Meanwhile I took the opportunity to clean up the swingarm and surprise surprise what I thought was minor surface rust turned into a horror show of holes when I took a wirebrush to it. I now have it back after taking it to a garage to be welded up and it's painted up with 2 coats of Hammerite. Should be good now for a few years!
I'm wondering what other horrors this bike might have in store for me. It's one of the last ST1100s made (2003) and is a reasonably low mileage (53000). I'm planning to do the timing belt after getting the MOT done.

Gareth

 

[Coucours Grad]

I would attempt to fill the hollows of that swing arm with oil.....Assuming all of the holes are sealed and its still accessible.

 

[garethjv]

I was thinking of doing something along the lines of this, but it's not clear that it's open. There are a few gaps at the top and bottom at the rear where the original welding is incomplete. Can I just pour engine oil into it through these and drain away the excess after letting it flow around?

 

[ST1100Y]

The issue are the "mild" winters in UK, enabling use of motorcycles year round, so running in brine you have on your roads...
This, paired with rarely washing the rig (to at least thin the salt accumulating everywhere...) is leading to this decay...

I'd add two additional drainage-bores on the backward cross-member of the swing-arm, and thread the cavities with ACF-50 or Waxoil...
The steel Honda used for swing-arm and frame is galvanized though, with a thin layer of primer and black overcoat, but nowhere resistant to permanent exposure to brine...

Also the collector, the connection pipes of the silencers and the exhaust clamps are exposed, and will suffer from that salt everywhere... copper-slip comes also as spray, it does help slowing corrosion on the exhaust system...

Remove the Tupperware, wash the rig, then preserve all and everything with ACF-50... yes, gonna be smelly for a few days :wink:
(did the engine/bay of my car, gave it that "new car smell" for a couple of weeks...)

You might also consider the shock-protector from Bike Quip extending that inner fender over the swing-arm, or use your own ingenuity there.

Running a motorcycle in salt-water, requires measures like when owning a yacht... :wink:

 

[HelmetHead]

I recently discovered a coolant leak, and have almost simultaneously developed a charging problem. My '94 has the original 28A alt. I was under the impression that the 40A device is rather different in external attributes as well as internal, and I wonder if you could comment as to whether brush-mucking via coolant drip is as possible on the 28A as the 40A discussed above...thanks much...

 

[Doodaa]

I recently discovered a coolant leak, and have almost simultaneously developed a charging problem. My '94 has the original 28A alt. I was under the impression that the 40A device is rather different in external attributes as well as internal, and I wonder if you could comment as to whether brush-mucking via coolant drip is as possible on the 28A as the 40A discussed above...thanks much...

They are two entirely different alternators. If you search the forums, you'll find many discussions about the 28 amp charging issues. See if any of the problems/solutions seem to fit yours. The biggest problem, IMHO appears to be faulty wiring connections due to age and lack of attention to this issue. Once this is an issue, it can snowball. Please insure you have a known good battery before digging too deep. There are plenty of resources here to help you and if you can't get it fixed, you should probably start your own thread for help.

 

[HelmetHead]

I am by no means dismissing your well-intentioned advice, and I am at the beginning of pursuing my problems on all fronts. I just happened to notice this particular thread came up in a search, and I wondered if the arrangement of external gaps in the alternator casing that apparently allowed coolant to get on the brushes is the same on the 40A and the 28A, such that ST1100Y's friend's problem could be part of the constellation of causes I'm looking at. Indeed, does the 28A have the same brush set-up the 40A has?

Any advice along those lines would be appreciated, just in case I get stumped along the way...for instance, I don't really want to go buy the Honda-approved multimeter, since I've got a perfectly decent one that's served me well for a long time, but...and, indeed, once I get further into testing, maybe I'll have a basis for starting a new thread. My question here is info-gathering re dis/similarities in construct of the two devices, neither of which I have ever seen...thx...

 

[DeanR]

Here's what the 40 looks like. and the 28

 

[John OoSTerhuis]

.... My '94 has the original 28A alt. I was under the impression that the 40A device is rather different in external attributes as well as internal, and I wonder if you could comment as to whether brush-mucking via coolant drip is as possible on the 28A as the 40A discussed above...

Short answer: no.

Your 28amp oil-cooled system has a sealed stator with an external, sealed VRR which is mounted at the end of a wiring harness next to the battery. The automotive style, air-cooled 40amp system has slots in the case which expose the windings to air flow, and the voltage regulator and rectifier are mounted right on the backside of the unit, also exposed (to air and water and dripping coolant from above). HTH.

John

 

[Doodaa]

Any advice along those lines would be appreciated, just in case I get stumped along the way...for instance, I don't really want to go buy the Honda-approved multimeter, since I've got a perfectly decent one that's served me well for a long time, but...and, indeed, once I get further into testing, maybe I'll have a basis for starting a new thread. My question here is info-gathering re dis/similarities in construct of the two devices, neither of which I have ever seen...thx...

From what I've gathered here from others here, the 40 amp is an air cooled, vented to the atmosphere, larger alternator. See the one on the left from DeanR in post 13. The 28 amp is the smaller, sealed in oil one, on the right (again the first picture, on the right). The picture on the right side (in post 13, by DeanR) shows the components to the 40 amp on the bottom and the 28 amp on the top. The post about coolant getting on the 40 amp enters thru the, open to the air, cooling vents which are not on the 28 amp unit. Many problems have happened on the open, 40 amp unit with our British brothers due to their weather unfriendly riding conditions of moisture and salt much more prevalent there. You 28 amp could not have this particular problem...it it sealed from the air and is brushless, (thanks ST1100Y) from my understanding. I follow both alternator size threads and, like you have the 28 amp unit, so causes and fixes are important to me. I have a "spark chaser" background and look for anything to avert the 40 amp upgrade wherever possible. (My mechanical abilities are not as good, but the people here are great in that area too)

You can survive without the special multimeter, but will come to a faster resolution of your problem by searching the forums for problems like yours and, if you don't find a satisfactory answer, start your own thread with your own problem, where many knowledgeable members here will be glad to offer suggestions, but may not see it buried within a thread for a 40 amp alternator issue.
Like you, I want to ride without issues, but you get much more better weather to do that than I. Hope this helps.

Sorry, while I was composing this, John gave you the short answer.

 

[HelmetHead]

Thanks very much for pix, Dean, which, coupled with John O's explanation and Dooda's confirmation alleviates my fear re coolant drip messing with my 28A. I kinda thought the two devices were enough different, as described by John O et al., that I was safe, but never even having seen the alternators, I was unsure. As you may suspect, I'm worried I'm at the front of what could be for me be (a daily rider with no back-up vehicle) a very nasty problem, so thanx all for clearing some brush in advance for me.

Battery looked good during battery store load test, but I bought a backup to get me through testing periods, so tomorrow begins 6P and 3P and 2P cleaning and testing.

 

[HelmetHead]

I've been slow on this issue (despite my daily ridership, now defunct for 5 days) because I not insignificantly hurt my (right/dominant) thumb-&-wrist recently.

Today I got the the 6P and 3P and 2P separated and tested the various circuits. All seemed fine, though I have not tested the VRR pins, partly because I don't have the requisite multimeter, and I did discover the melting described below.

Saw black, melted plastic (of the 6-pin white connector that shoves into the bottom of the VRR) around the yellow (alternator) input line designated #5 on page 17-6 of the ST1100 manual. That connection, #5, is the alternator-to-VRR input line immediately next to the wall of the VRR and the bike frame.

I have questions about how I get around this problem, which I will post in a new thread under the general ST1100 Tech forum, since this seems not to be an alternator problem.