40/28 amp St1100 Alternator - Please help me

Johnny8718

Johnny8718

Joined
Nov 25, 2011
Messages
6
Location
Wigan
Hi All.

New to the forum but not new to the Pan European.

I have bought a 1996 non ABS model which has an absolutely abolished alternator. It would appear that the previous owner had laid up the bike whilst alternator was seized. When he tried to recomision the bike, he ignored this and broke the casing - very badly and smashed it to bits.

That's where I come in. I bought the bike this month with a broken alternator, not realising that there was such an issue. I have removed the 40 amp unit to find that the alternator is ABSOLUTELY beyond repair. However when I have trawled the Internet, eBay etc etc - I CANNOT source a replacement at all.

I have approached approximately 35 breakers (no exaggeration). I have requested a refurb from 3 separate independent alternator refurb companies. The answer is a big fat no as even with the NIPPON DENSO serial number, they cannot find the parts. I stand to face breaking the bike and quite simply, it is worth more than that!

My questions are simple

1) Does anyone IN THE WORLD, have a 40 amp alternator that I could buy?
2) Radically, can anyone advise how I actually convert the bike to a 28 amp unit?

Issue is, the 28 unit can be purchased for ?100 second hand, but the 40 amp unit is only readily available as a new unit at a staggering ?600!!!!!

Please don't tell me that 40 - 28 is the wrong move, I know what you mean, I really do. If this gets the bike on the road again however, I am happy with limited electrical options. There are plenty of people out there swapping the 28 amp unit for a 40 amp unit - but how about the other way?

Unless I find an affordable answer - the bike has top be broken for bits.

PLEASE PLEASE PLEASE HELP.

John.


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I am here: http://maps.google.com/maps?ll=53.493143,-2.626213
 
The 40 to 28 is the wrong move. I know you said not to say it but it really is. I know you said you looked for new ones ant they were 600 GBP. (sorry I don't have that fancy L on my keyboard). Have you looked into sources here in the US? They are a available here. 600 GBP = about $1000. Last I looked a new 40 amp is about $440. Shipped you might be able to get one for about 300 GBP after currency conversions. I just can't tell you which online parts source will ship overseas but worst case someone here might be willing to help out by buying locally and shipping.

If you were to do the conversion the other way you are going to need more than just the 28 amp alternator. You will need a Voltage Regulator Rectifier and need to tweak the electrical harness a bit. Basically follow the directions on doing the 28 -> 40 and do the opposite.

Really if you were to buy a second hand 28 you are gambling. It could be on its last leg. A new 28 would be better but at the cost your best option would be to try and source one from the US. They are much cheaper here.

A couple places you could check with are.

http://www.servicehonda.com
http://www.ronayers.com/
http://www.ronayers.com/Fiche/TypeI...1100A/GroupID/315140/Group/ALTERNATOR_-_96-98

In the UK have you tried here?
http://www.davidsilverspares.co.uk
Silvers shows the 40 Amp for 475 GPB. Not a steal but it is new and much less than 600 GPB.
I know you have a non ABS but the part is the same.
http://www.davidsilverspares.co.uk/ST1100AT-ABS-PAN-EUROPEAN-1996/part_77758/

Hope this helps some.
 
Keep on looking for the 40 amp. One will come around sooner or later. I lucked out and got another alternator, with an entire engine attached, for $300!
 
The 40A alternator fails more often than the 28A one here in the UK, due to its exposed position allowing corrosion through the air slots, compared to the sealed oil-cooled smaller version. Road salt used in the UK is particularly corrosive.

If you fit an uprated voltage rectifier/regulator (with heatsink, as was supplied with police ST1100s), and fit some HIDs to lower demand on current, a 28A alternator should be less troublesome than its "improved" bigger brother.
 
Thanks all. Definitely a few options to think about. Keep the replies coming!

I have looked at the american links and have emailed the companies for more info. Thank you.

I have received a PM from one forum user who can supply me with a used unit but the carriage is extortionate. ?80 if I was sending the alternator to the US. US to UK, try doubling it. What is that all about??? There just seems to be stumbling blocks whatever I consider.

Hound. You mention a regulator from a Police Spec bike. Do you have any further details?

Does anyone know what I need to do to wire up the old type alternator. This is going to be by far the cheapest of any option open to me and on UK salted roads would appear to be the long term solution as the new 40 amp unit seems open to the elements here in good old blighty.

Thanks, John.
 
John . Sorry not much technical help from me but this company are breaking a couple of bikes on E bay uk. They might have slipped through your search as they are not advertised as specific parts yet.


'ANY QUESTIONS PLEASE CONTACT:

GEORGE AT VILLAGE MOTORCYCLES.

Tel:- 07907 684 592'

and a link to one of the bikes that they are breaking-

http://www.ebay.co.uk/itm/1999-HOND...9187626?pt=UK_Motorcycles&hash=item336e9e1baa

The remainder of the bikes are listed under 'view other items' tab.
Cheers
 
Thanks for that.

This guy is literally 15 minutes from me. He has a list of people waiting and mentioned that this bike was coming in.

Trouble is, the demand means that the alternators go for almost the same price as a new one. It is ridiculous. If I was riding a Suzuki Bandit, I could buy a second hand (almost identical unit) for a mere ?20! And, I HAVE considered this - sadly no! :(

Thanks for the update though, I may just send him an email and see what he suggests.

Cheers John.
 
My answer may be to buy the 40amp unit from the US. The seller has been great and has managed to find a courier who can ship for a lot less than I can find a quote.

One last question on this though before I go ahead.

Does anyone know how easy it would be to fit the 28amp unit? If so, how?

I can source the 28amp alternator and rectifier here in the UK for less than ?90.

Thanks, John.
 
Honestly I don't know of anyone that has done this swap. It will be similar to the 28-40 conversion. What needs to be done to get to the alternator is the same. Basically two options, either pull the engine or pull the swing arm. Most go the swing arm route. Where the process will differ is the changes to the electrical system. The VRR on the 40 is built into the alternator. The 28 amp had an externally mounted one that needs to be hooked up.

In all honesty I can't be a ton of help here. I haven't done a 28-40 conversion so I don't know what needs to come off or in you case put on. I do know that the 28-40 conversion needs another circuit. Some go with the newer fuse block, add an aux or just a fuse. So don't panic if you have an extra circuit that doesn't appear to be needed.
 
sennister said:
Honestly I don't know of anyone that has done this swap. It will be similar to the 28-40 conversion. What needs to be done to get to the alternator is the same. Basically two options, either pull the engine or pull the swing arm. Most go the swing arm route. Where the process will differ is the changes to the electrical system. The VRR on the 40 is built into the alternator. The 28 amp had an externally mounted one that needs to be hooked up.

In all honesty I can't be a ton of help here. I haven't done a 28-40 conversion so I don't know what needs to come off or in you case put on. I do know that the 28-40 conversion needs another circuit. Some go with the newer fuse block, add an aux or just a fuse. So don't panic if you have an extra circuit that doesn't appear to be needed.
Click to expand...

Thanks.

Alternator is already off via the swing arm route. Looking at the wiring diagrams, my friend and I are considering splicing into a good earth on the bike with the earth from the voltage regulator, the live red/yellow wire straight to the positive terminal of the battery via an aftermarket fuse block.

Does this sound OK?
 
John, pics of the police-spec VRR below. The Honda part number is 31600-MZ9-901 but it is extortionate: there's a pattern part on eBay which is somewhat cheaper .
 

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Rewiring for the old style alternator should be fairly simple, add the three yellow wires between the VR/R and the alternator, plus one other wire if I remeber correctly. Given the difference in price and the added factor of a "sealed" unit, 28 might be the better choice.
 
Johnny8718 said:
Alternator is already off via the swing arm route. Looking at the wiring diagrams, my friend and I are considering splicing into a good earth on the bike with the earth from the voltage regulator, the live red/yellow wire straight to the positive terminal of the battery via an aftermarket fuse block.
Does this sound OK?
Click to expand...

That sounds right, John.

edit: rereading, I'm not sure now what you mean by the VRR earth...

If you can get the salvage yard to strip the wiring loom on the donor 28amp ST so the 6P wiring comes out complete with the red 3P:
Connectors.jpg


that'll help reduce the snipping and splicing while converting the 40amper's wiring to accommodate the 28amper. You'll need to tap into the 40amper's black lead short of the the little black connector. This connector is common to both models but only carries the one black wire on the 40ampers, but has the additional white wire on the 28ampers. Ask the 'breaker' for the 28amper's black 2P version with enough wire lead length for splicing. Best case would be if the breaker could include the wiring harness intact with the black 2P (w/white wire and only the black lead snipped). Worse case would be to just snip out the black 2P connector and make your own. The red/white-stripe wire needs unswitched power as you noted, either separate fused lead direct from the battery pos post or added (plug a female spade connector in) to the red 4P main-fuse/starter-relay connector like the 28ampers.'

Here's some colored ST1100 wiring diagrams to compare to each other that should be very helpful getting the rewiring set:
http://www.st-riders.net/index.php?topic=3908.0
these two in particular, downloaded and viewed side-by-side in your favorite image viewer, or just print them:

edit2: or, right-click on each in turn, open in a new window and resize them for side-to-side on your monitor...

(28amper - file name: wiring diagram st1100 91-95 std 2.jpg ):
http://www.st-riders.net/index.php?action=dlattach;topic=3908.0;attach=4048;image
(40amper - file name: wiring diagram st1100 96-97 std 2.jpg):
http://www.st-riders.net/index.php?action=dlattach;topic=3908.0;attach=4056;image

HTH Interesting proposal, John. Thanks for the mental exercise. :)

Regards, John
 
Last edited:
To all of you, a very big thank you.

I have shown my friend the threads and we are now confident that the 28amp setup is the best, most affordable for my needs.

John. Your diagrams are really helpful - Cheers!

I will let you all know what happens in the next few weeks.

John.
 
I am having exactly the same problem getting hold of a 40amp alternator, there is a one listed on ebay at the moment
in Modesto USA but the seller will not ship to the UK and I have asked him twice to change his mind.

anyone got a spare please
 
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