ST1100 Charging problems.

Merrowman

Merrowman

Joined
Jan 7, 2012
Messages
6
Location
Portsmouth, Hampshire, United Kingdom
Bike
1998 ST1100AW
I've got a 1998 ST1100AW. A few weeks ago I was out on the bike and it seemed the battery didn't have too much puff left. About 100 miles from home I had to fill up with fuel and needed to jump start it. Riding home in the dark the lights were getting dimmer and dimmer, until after about 75 miles you could barely see them. I decided to pull off the road, and as I switched on the indicator the bike just died. Stopped to find the battery virtually flat. Got recovered home, thinking regulator/rectifier fault. Put the battery on slow charge, and after a couple of days came back to it. Checked all the easily reachable wiring, fuses etc, cleaning where necessary. Bike ran okay but voltage checks showed I still had a problem. Took it apart again and fully charged the battery, then along came Christmas and everything stopped! Today, after a couple of weeks, I returned to it. Battery had been standing, off-charge and off the bike, for about 10 days and was showing 12.8V. The bike cranked sluggishly at first, and fired up after about 5 seconds. Running at about 2000rpm the voltage across the battery was 14.2V - I think a reasonable charge. Switched on sidelights, dropped to 13.4V initially before crawling back up to 14.2V. Switch on headlights and the charge voltage dropped to around 12.8V and stayed there, even on revving to 5000. Lights off again - 14.2V. Found that whatever extra I switched on dropped the voltage, and the headlights' additional 9 amps was enough to kill any charge.
Battery does seem to hold a charge OK, but it is the same Yuasa battery that was 'not new' when I bought the bike 7 years ago! Now I'm not sure if its R/R or not - hope not, now that I've found that it's built into the alternator - expensive and a pig to get to! There is some corrosion in some of the wiring (bikes had a hard life - in use all year round), but all the connections I can get to seem clean enough. Could it be mucky connection dropping the voltage,or is it more likely to be Reg/rect, alternator or battery? Clearly I don't want to strip out the alternator and pay a fortune for a replacement just to find it needed a new battery! I've noticed some others have had broadly similar problems, how did they cure it? Any ideas?
 
Welcome!
The first thing to look at is your connections. Are the screws on the battery tight. They are known to loosen up and then you get problems.
 
Thanks for the speedy reply! All the connections I can easily get at are now clean and secure, but still got to crawl under the bike to check the alternator connections and a couple of loom connectors. Will post back when I've done so. Just hope it's that simple!
 
I have never seen anyone post about problems with the Alt. I has been the + and - on the battery.
 
There have been several posts on issues with the 40 amp alts due to salt exposure and corrosion. Most have occurred in the UK. Could be the regulator/rectifier pack. You'll want to check all the connections and voltage output first, but you may end up having to pull the alt for repair/replacement. That process is well documented.

There are repair parts available for the alt; bearings, brushes, regulator/rectifier. As long as the windings are ok, it's rebuildable.
 
I've been posting regarding repairing the small frame ND alternators for years. Parts are available from automotive sources for everything excepting the drive-end housing and the rotor shaft. Someone on My-Mc or one of the ST groups found a specialty shop in the UK which repaired the alternator so you may wish to search a bit. Those little alternators are very reliable but need either experience or great care in disassembly if the rotor frame is corroded and stuck to the end frames.

The tests in the manual are nonsense, IMO so don't bother with them. Just test to make sure that you have a good connection between the heavy alternator (output) wire and the battery. It would be worth while either using a heavy jumper wire or load testing from the alternator end. As someone mentioned, the wire between alternator and battery is not a failure area of note for these systems, unlike for some others.

The smaller wire is switched power by the ignition switch so should show such with key on. Again, I like to load with something like a heavy bulb to ensure that there is a circuit there or check voltage with the wire plugged into the alternator.

Something else which is not mentioned in the manuals is the "full circuit tab" in a hole in the rear cover of the alternator. This is a Type "A" alternator so the regulator controls field (rotor) current on the ground (earth) side. The tab allows a tool to be used to connect the tab to the alternator end frame with engine running to see if the alternator will charge. It should go full out which you will hear by the whine and engine loading so don't hold it on for more than a second or two to avoid driving system voltage too high and causing problems. If you have power to the two alternator leads, and it will not charge with the tab grounded, it needs to come out and be pulled down to see what is the issue. If it does charge by grounding the tab, the regulator (again, internal) has failed but you will know that by the test. I posted a photo into My-Mc (the old site) as well as photos showing the disassembly of the alternator a year or two ago.

One failure area which has been addressed successfully was a broken rotor field wire between the slip ring and rotor winding. Two or three members of My-Mc have solder repaired the wire and used epoxy to support the repair. Honda do not supply parts for this alternator because, IME, there is not enough call for parts. The conspiracy nasties will please go away because am not interested in hearing.

A professional alternator repair shop will be able to disassemble the rotor and replace the field winding for about $100 here in Canada and you should find one there. Don't bother with a bike shop as they are not in this business unless things are radically different than here. Check some of the later alternator threads and am sure that you will find the UK poster who mentioned the UK shop. In this part of the world use: "Specific Rebuilders, on London Avenue in Mission City, BC, Canada. Ask for Mike Cook who is the owner and a hugely smart guy with regards alternators. Mention my name but don't say I said that he's really smart as I don't want him to get a swelled head. (VBG)

Please post how you make out with the repair.

PM if I can help,

Norm
 
Well, I'm ashamed to say it's taken me months to get round to fixing the bike - mainly due to other commitments... and the fact my son now has a bike I can borrow!
Having tried everything else I could think of, I eventually bit the bullet and removed the alternator. I found the casing swollen and cracked, and I needed to use a wrench to turn the thing! In short, the alternator is totalled - another victim to the demon that is road salt corrosion. After looking around on E-bay and the like for second-hand ones (like gold-dust and very over-priced due to the popular 28A to 40A mod!), I eventually decided to lash out and buy a new alternator. These are outrageously expensive but I did find out one thing - I contacted David Silver Spares (UK Honda specialists) and found the price of a new alternator from Honda was ?630, but they also had an 'OEM' one listed for ?468. I queried this, and the guy said the OEM one was made by Denso. Bells were ringing as I bought the OEM one quick before they changed their minds. When it was delivered I can confirm it was exactly the same as the original (also made by Denso) - same labelling, same part number, everything (except of course this one works!). The moral is, if you need one, buy the Denso OEM one and save loads!!!
Anyway, while I had the back end stripped off the bike I decided to go right through, treat any rust and remove and replace all fixings using 'Copper Ease', then took off all the panels and gave the bike a well deserved full service - with 61,000 miles on the clock I figure she deserved some TLC. Done the work over the last few weeks and put her back on the road a couple of days ago, just in time for the sunshine! She runs beautifully, and it feels so good to be back on the road!
Thanks to all who gave advice and support, Hopefully we'll meet along the road somewhere. Stay safe!
 
Merrowman said:
....Anyway, while I had the back end stripped off the bike I decided to go right through, treat any rust and remove and replace all fixings using 'Copper Ease'....
Click to expand...


Congratulations!

Question: Is "Copper Ease" the same stuff as "Copaslip?"

Just a curious Yank....
 
Cheers, Digger1. Yes, Exactly the same stuff - copper-based anti-seize compound. I've always used it on brake and exhaust fixings, as they tend to seize anyway, just through heat, but having had to drill out about 8 to 10 bolts that had seized solid just to get the fairing off, I decided that any fixings I could see and undo I would do so and a apply a large dollop of said gloop, so hopefully they won't seize again. We have real problems with road salt here in the UK, and it gets everywhere. Still, the main thing is that the bike is back.
Thanks for your interest. Stay safe.
 
Merrowman said:
We have real problems with road salt here in the UK, and it gets everywhere.
Click to expand...
The issue are your mild winters, actually permitting riding, whilst we here get buried in snow, so the bikes hibernate well protected in the garage/hangar...
If you want to preserve your new alternator as good as possible, I'd suggest giving it an annual layer of ACF-50 (as recommended by another Britt gentleman...), a penetrating, corrosion stopping solvent used in naval yards and aircraft maintenance which in particular will prevent the iron stator plates from corroding, thus 'swelling' till the aluminum casing cracks. It actually conserves all metal parts brilliantly, rotors and calipers shall be avoided though ;-)
 
Merrowman said:
I've got a 1998 ST1100AW. A few weeks ago I was out on the bike and it seemed the battery didn't have too much puff left. About 100 miles from home I had to fill up with fuel and needed to jump start it. Riding home in the dark the lights were getting dimmer and dimmer, until after about 75 miles you could barely see them. I decided to pull off the road, and as I switched on the indicator the bike just died. Stopped to find the battery virtually flat. Got recovered home, thinking regulator/rectifier fault. Put the battery on slow charge, and after a couple of days came back to it. Checked all the easily reachable wiring, fuses etc, cleaning where necessary. Bike ran okay but voltage checks showed I still had a problem. Took it apart again and fully charged the battery, then along came Christmas and everything stopped! Today, after a couple of weeks, I returned to it. Battery had been standing, off-charge and off the bike, for about 10 days and was showing 12.8V. The bike cranked sluggishly at first, and fired up after about 5 seconds. Running at about 2000rpm the voltage across the battery was 14.2V - I think a reasonable charge. Switched on sidelights, dropped to 13.4V initially before crawling back up to 14.2V. Switch on headlights and the charge voltage dropped to around 12.8V and stayed there, even on revving to 5000. Lights off again - 14.2V. Found that whatever extra I switched on dropped the voltage, and the headlights' additional 9 amps was enough to kill any charge.
Battery does seem to hold a charge OK, but it is the same Yuasa battery that was 'not new' when I bought the bike 7 years ago! Now I'm not sure if its R/R or not - hope not, now that I've found that it's built into the alternator - expensive and a pig to get to! There is some corrosion in some of the wiring (bikes had a hard life - in use all year round), but all the connections I can get to seem clean enough. Could it be mucky connection dropping the voltage,or is it more likely to be Reg/rect, alternator or battery? Clearly I don't want to strip out the alternator and pay a fortune for a replacement just to find it needed a new battery! I've noticed some others have had broadly similar problems, how did they cure it? Any ideas?
Click to expand...
7 years on a battery ! Best I've heard of with reasonable use , 3 years with today's quality questionable , have heard favorable reviews of Interstate ,
ST1100Y said:
The issue are your mild winters, actually permitting riding, whilst we here get buried in snow, so the bikes hibernate well protected in the garage/hangar...
If you want to preserve your new alternator as good as possible, I'd suggest giving it an annual layer of ACF-50 (as recommended by another Britt gentleman...), a penetrating, corrosion stopping solvent used in naval yards and aircraft maintenance which in particular will prevent the iron stator plates from corroding, thus 'swelling' till the aluminum casing cracks. It actually conserves all metal parts brilliantly, rotors and calipers shall be avoided though ;-)
Click to expand...
 
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