1994 Honda ST1100 - 28 Amp Alternator Died; Need to Upgrade to 40 Amp Alternator

Joined
May 20, 2015
Messages
4
Location
Bellevue Nebraska
Bike
1994 Honda ST1100
After more than 26 years, I'm finally a owner of a very nice, low mileage 1994 Honda ST1100 that was posted on this forum last month. The bike is in absolutely tremendous shape and the previous owner took extremely good care of it. After my 1700 mile trip home the OEM 28 Amp alternator died. I need to replace the alternator and after being a member of this group for about 2 years, it looks like I should upgrade to a 40 Amp alternator. Question: Where can I order all the parts necessary to make this happen? Are there any genuine Honda alternators for ST1100s still available? Does anyone know where I can buy this part? Thanks all for your help - I can't wait to start riding this bike again! Gregory Smith, MSgt, USAF (Retired)
 
Joined
Jun 3, 2006
Messages
3,513
Location
British Columbia
Bike
2021 RE Meteor 350
The 28 amp stator is now obsolete and not available through Honda. Some used ones come up on eBay. The parts for the 40 amp upgrade are all available through Honda (try Partzilla) and there is a kit for helping with the job available through this forum. John O. (on this forum) is the 'manager' of one such kit. Complete instructions also available through Mike Martin's ST pages.

http://koczarski.com/mmartin/Alt.htm
 

Jonb

Red Arr00w
Joined
Apr 27, 2008
Messages
133
Location
Manchester, NH
Bike
06 ST1300
STOC #
7537
Get a good manual and follow the electrical test procedures. It might just be the voltage regulator. Upgrading the to 40 amp however is a great way to go as you can add many electrical farkles and heated gear.
 

sirepair

Let's RIDE!
Site Supporter
Joined
Jun 7, 2007
Messages
3,231
Location
Chillicothe, Ohio
Bike
2003 ST1100P
STOC #
7105
There is a used 40 amp on ebay: http://www.ebay.com/itm/2002-02-Honda-ST-1100-ST1100-Alternator-Generator-101211-1570-/253133092974?fits=Make:Honda|Model:ST1100&hash=item3aefe8786e:g:Cb4AAOSw4i5ZrJ9j&vxp=mtr

Includes the drive parts needed to install. You could get this one and clean it up. You might want to replace the bearings and regulator before installing it as I did. Write up on that here: https://www.st-owners.com/forums/showthread.php?55159-Alternator-bearing-replacement

Friggin' Photobucket! Can't even download my own pictures! What a PITA!! I'll get this figured out so I can get the pictures back.
 
Joined
Jul 30, 2018
Messages
3
Location
CT
Get a good manual and follow the electrical test procedures. It might just be the voltage regulator. Upgrading the to 40 amp however is a great way to go as you can add many electrical farkles and heated gear.
I wouldn't try to follow the Honda Service manual to diagnose alternator - confusing!!
 
Joined
Apr 7, 2021
Messages
1
Age
26
Location
Ohio
The 28 amp stator is now obsolete and not available through Honda. Some used ones come up on eBay. The parts for the 40 amp upgrade are all available through Honda (try Partzilla) and there is a kit for helping with the job available through this forum. John O. (on this forum) is the 'manager' of one such kit. Complete instructions also available through Mike Martin's ST pages.

http://koczarski.com/mmartin/Alt.htm
I cant find one on part zilla is it hard to retofit the 40 amp
 
Joined
Oct 17, 2014
Messages
911
Location
Tacoma, Wa
Bike
2010 ST1300
I cant find one on part zilla is it hard to retofit the 40 amp
Good morning/afternoon,
We regret to inform you that the 40amp alternator base plate P/N 11202-MAJ-G20 has had a part number change. It is no longer discoverable except under P/N un-obtain-ium. We hope that this helps you in the search for Elysium.

Regretfully yours,
Honda
 
Joined
Jun 3, 2006
Messages
3,513
Location
British Columbia
Bike
2021 RE Meteor 350
I cant find one on part zilla is it hard to retofit the 40 amp
If you have a modicum of mechanical skills and the tools to do the job, it isn't terribly difficult to do the upgrade. There is a kit with some necessary bits to do the job available for your use, free of charge except for postage. You need to contact John O. on this site, who is the keeper of the kit.

Also, do you have the Honda, or the Clymer Service manual for your bike? The Clymer has a pretty good description of the upgrade process. I'm going to look up some other links to reports of doing the job and will post them here shortly.
 
Joined
Aug 21, 2018
Messages
6,654
Location
Richmond, VA
Bike
'01 & '96 ST1100s
STOC #
9007
Good morning/afternoon,
We regret to inform you that the 40amp alternator base plate P/N 11202-MAJ-G20 has had a part number change. It is no longer discoverable except under P/N un-obtain-ium. We hope that this helps you in the search for Elysium.

Regretfully yours,
Honda
Fortunately, you can buy it with or without parts here:


 
Joined
Jun 21, 2021
Messages
2
Age
73
Location
Rochester, NY
Bike
Honda ST1100
If the 28A is obsolete, I can understand the upgrade. But if you upgrade to a 40A alternator, you are still running with a 20A electrical system. Wire sizing is not an issue?
 

kiltman

Site Supporter
Joined
Apr 27, 2013
Messages
3,280
Age
68
Location
Stratford, Ontario Canada
Bike
2002,ST1100ABS
STOC #
8826
If the 28A is obsolete, I can understand the upgrade. But if you upgrade to a 40A alternator, you are still running with a 20A electrical system. Wire sizing is not an issue?
Yes and no.
Each accessory will still draw the same wattage wether you have a 28 amp service or a 40 amp service and the OEM wiring is geared for that. The weak link is the wiring to the main relay and there are bypasses that can be employed to deal with that. As a result of a higher capacity that the 40 amp service can give you, more circuits can be added via either by an additional fuse block or individual fuses, using appropriate wire sizes for the wattage of said added accessory.
 
Joined
Apr 8, 2017
Messages
174
Location
Utah
Bike
1994 ST1100
STOC #
9042
I up graded my '94 ST1100 from the 28 amp to the 40 amp last year. You CANNOT get the alternator base plate anywhere except from the fellow who is manufacturing them. I know, I searched for months. My advise to anyone thinking about doing the 40 amp upgrade, having just done mine,

1- buy this kit now. It has all the major parts you will need. It'll save you months trying to round up all the parts you need. https://www.ebay.com/itm/114859879844?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20200818142401&meid=0bb2a6a633d14a54a25ad358a2dc3339&pid=101124&rk=1&rkt=12&sd=114750827750&itm=114859879844&pmt=0&noa=1&pg=2563228&algv=DefaultOrganic&brand=Honda&_trksid=p2563228.c101124.m2109

2- Buy a new 40 amp alternator. Everyone wants a genuine Honda, but chances are they are chinese anyway. I actually got mine from walmart.com. https://www.ebay.com/itm/324358349320?_trkparms=aid=1110018&algo=HOMESPLICE.COMPLISTINGS&ao=1&asc=232958&meid=0fbc2f58d4964d4e950d6c549d3afa5f&pid=101196&rk=1&rkt=12&sd=114859879844&itm=324358349320&pmt=1&noa=0&pg=2047675&algv=ItemStripV101HighAdFeeWithCompV3Ranker&_trksid=p2047675.c101196.m2219&amdata=cksum:3243583493200fbc2f58d4964d4e950d6c549d3afa5f|enc:AQAGAAACAJ1xOIeTuwRjlAyhAOOBi4IQl8Mc1UPceyLbo0mrXLeJlqFtIhLeL6bYib2jLTc7xboukD8dhiGPCSqUnGG26au%2FCmk0nISHrNkqEH6TJRI6IQdK8bfMh0ScJOn0G61Jfbt5Ioa3uHbpTmKJeP%2F%2BFIKfyzIswNIQMwkgLHD8sbsuySoFA1U4Jw2c7lJ%2BEcWlyu0jVyefbk0cqIq%2B%2BMuxoUPOP%2BygLJJFFGzuoYd0u0TcrWwVOOqhLVtY%2Ftvisu9N4ZYR4hm4ys2lIc7KkH26n35mWUvy9OzHtkMCAcuM2scynCs0mXF53Mk3htfNPgeLdMJ%2BNF9tzUTD2y8eSeXwce%2FCJFYhBCnu74wLrP3y%2F0qvJ%2FeVVaQWxOEpLpzPIaZptR8IQFM808sIFiNnFwzUtvObRyGB%2BHsyr5UpwQIf8HqspBDj7NYnZPrXtopeaIo7apl8d5cxVHZBqtO6GEGjLc6GCfkZI05Bjh2n5RjgkhAvjrL7v19BuVUKI5YP97YDm4gH6948jldlhU9aij4iyMZoDOmebLT5BEcESQaqKsrvduu7oKJXP6%2FSwbDY4seQ5PBzllxZhoOXUDcpnWFt3vm3LcOCFqvQjjV%2BDPy%2B3vfGFcx29cBBlsOkpbdijtt0pZl5eReFE9r5vT6UNncXE2noaxidpdHeGGECB1xk2R3O|ampid:pL_CLK|clp:2047675

3- Get with John Oosterhuis <GreyGhOOST@mchsi.com and get the traveling install kit coming your way. It has all the tools, instructions and just about everything you'll need to do the upgrade.

4- here's the write up I did on my install https://www.st-owners.com/forums/threads/94-st1100-40-amp-alternator-upgrade-completed-woo-hoo.173478/

If I'd had this information before I started my install, it would have saved me months and a load of confusion and frustration.
 
Last edited:
Joined
Apr 8, 2017
Messages
174
Location
Utah
Bike
1994 ST1100
STOC #
9042
For those who need to do this, is a suitable pin-on-a-leash part of the kit?
There's one in the kit. There's also a plastic tube to assist in threading the wire leash up through the drain hole. The kit has a single wire attached to the pin that broke when I did mine. Maybe used too many times? So I added a strand of picture frame wire ( I included a roll in the kit) to it then it worked fine.
 

wjbertrand

Ventura Highway
Joined
Feb 8, 2005
Messages
4,407
Location
Ventura, CA
If the 28A is obsolete, I can understand the upgrade. But if you upgrade to a 40A alternator, you are still running with a 20A electrical system. Wire sizing is not an issue?
No single individual circuit is going to draw more amps with the 40A unit installed vs. the 28A unit. The beauty of the 40A unit is that it better handles multiple circuit demands including added accessories. It also has better output at idle and slower in-town speeds, something the 28A could not keep up with. My '93 ABS would start throwing an ABS code 8 in slow traffic as it could not handle the cycling of the cooling fan, brake light load and ABS system demands resulting in drawing down the battery. This was happening with no added accessories at all.
 

John OoSTerhuis

Life Is Good!
Joined
May 10, 2005
Messages
5,218
Location
Bettendorf, Iowa
Bike
1991 SSMST1100
STOC #
1058
For those who need to do this, is a suitable pin-on-a-leash part of the kit?
There's one in the kit. There's also a plastic tube to assist in threading the wire leash up through the drain hole. The kit has a single wire attached to the pin that broke when I did mine. Maybe used too many times? So I added a strand of picture frame wire ( I included a roll in the kit) to it then it worked fine.
The link to all the STOC loaner tool kits (Link) and the one to the Alt Upgrade Kit (Link) [register]. Here’s a picture of some of the tools (the Lewis-Pin is #2):

ADFD12A5-52D1-45F9-AF1B-18D68AF50745.jpeg

This is the original pin made by Jon Lewis himself and donated to the ST community. Hardened steel slightly larger than 6mm and with a shoulder to fix the insertion depth. 170+ successful upgrades. The whole kit:

46A1CA18-E9AA-4530-843A-59C4DC259AF6.jpeg

John
 
Last edited:
Top Bottom