28amp Alternator

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Feb 7, 2015
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Cambridge U.K
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1994 st 1100
Hello all
i have to change my alternator on my st 1100 1994 48000 miles.As i am in U.K and i don't run any extra electrical items i am thinking of just a straight swap .My confusion lays in what parts do i need for this .I have looked at the 40 amp upgrade parts to try and compare the bits i will need. Do i need all of these for a swap.If possible could someone give a a list of the parts.I know you will say change to a 40 amp but i have limited skill and if i get another 48000 miles out of it i will be happy
regards
Noel.
 

kiltman

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Is your plan to replace it with a fully functioning 28 amp alternator? Do you have a manual? it should tell you what sundries you may require, as in gaskets etc.

Before replacing make sure the red connector and the white connector to the VRR is in good shape, no burnt out wires. Otherwise your replacement may experience trouble as well.
 

Mark

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Actually, I think according to 'Hound' the 40amp doesn't handle your road treatments as well as the 28 amp...
You might want to PM him and find out his recommendation for your side of the pond.
 
OP
OP
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Cambridge U.K
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1994 st 1100
Thanks for replying
I have looked on Partzilla USA and been quoted including delivery $798 , second hand no guarantee in U.K $368 ish.
Wires seem ok no burns
Will try and contact the Hound
thanks again
 
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Thanks for replying
I have looked on Partzilla USA and been quoted including delivery $798 , second hand no guarantee in U.K $368 ish.
Wires seem ok no burns
Will try and contact the Hound
thanks again
'Wires seem okay' isn't goona work. The plug-in connectors is where contact issues and electrical resitance occurs......resulting in the likelthood of your alt. demise;). Unplug all connectors associated with the voltage regulator, spray clean with De-Oxit or other high quality electrical cleaner. After which a dob of dielectic grease in each connector BEFORE plugging them back together is reccomended......ESPECIALLY in your location! The 40amp. so called 'upgrade' being exposed, air cooled and not sealed may or may not be a good choice based on your location. In other words, other than output increase, the 40amp. alt. is NOT a magic 'fix'all';).

Bottom line is electrical connections may 'look' good to the naked eye, but is not necessarily the case:).
 
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Thanks for replying
I have looked on Partzilla USA and been quoted including delivery $798 , second hand no guarantee in U.K $368 ish.
Wires seem ok no burns
Will try and contact the Hound
thanks again
If you want to keep with a 28 amp system, you only need to order the "Cover Assembly" (stator housing) #31130-MT3-003. The o-ring comes with the stator assembly in the box. That part is $317.60, so methinks you have been looking to order too many parts, since there's no way the shipping would be over $300.00!:confused:

If you don't plan to add a bunch of electrical farkles, you should be fine sticking with a 28 amp system. I agree with all that Brant said, except I would suggest you eliminate any future wiring issues by removing that red 3P connector and soldering and shrink wrapping the three yellow wires instead.

I just did this job on my (now sold) '95 1100 and I did face a couple of problems that started when two of the three stator housing bolts sheared off upon removal. They are pretty thin bolts! If you encounter problems there, check out my previous thread on that.

Just to add, the three stator housing bolts go into open ended holes, so if you can manage to spray some penetrant in back of them first (it is awkward), that may help, as the steel to aluminum corrosion on those threads can really seize them. I didn't realize that before I tried removing mine, although, the way those bolts were seized it may not have helped at all anyway.
 
Last edited:
OP
OP
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Cambridge U.K
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1994 st 1100
Thanks for all of your advise
I will check all the connectors and treat as advised .
I was looking at both parts of alternator including drive gear so that was why price was high.
I'm glad i just need the cover assembly as that has helped with cost.
When i remove the rear end i see from Martins page a list of optional bits to replace on rear end
are there any parts i will defiantly need
 
Joined
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2021 RE Meteor 350
Thanks for all of your advise
I will check all the connectors and treat as advised .
I was looking at both parts of alternator including drive gear so that was why price was high.
I'm glad i just need the cover assembly as that has helped with cost.
When i remove the rear end i see from Martins page a list of optional bits to replace on rear end
are there any parts i will defiantly need
One thing you will definitely need is the special Honda tool, or one made like it, to properly torque the swing arm bearings. Other than that, you may want to replace the three o-rings in the rear wheel hub assembly. You also should have the Honda Moly 60 to lube the rear drive splines and the driveshaft splines. With only 48,000 miles, the driveshaft u-joint should be fine, but you should replace the rubber boot that protects the engine output shaft to driveshaft connection point.

Do you have the Honda Service Manual? It does a good job of detailing this operation.
 
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ST1100Y

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If you want to keep with a 28 amp system, you only need to order the "Cover Assembly" (stator housing) #31130-MT3-003. The o-ring comes with the stator assembly in the box. That part is $317.60
I've to agree... (DS carries the stator for GBP 311.16,- http://www.davidsilverspares.co.uk/parts/by-part-number/hpart_31130MT3003/ , might be cheaper there due lower freight costs)

The oil-cooled, thus hermetically sealed 28A unit is quite unimpaired by environmental effects (like the brine on wintry UK roads...), its wiring connectors however do require some maintenance.

Before starting to order any parts I'd give the entire charging system/wiring a throughout check and carefully rebuild/replace anything that doubts, to avoid any cascading failures (as such could blow a new stator winding...)

I also have a '94 with 195Tkm/122K-miles on the clock, on which I'd to replace the stator (sudden short to ground), easy job and the charging system works like new again.

One additional tip: the VRR utilizes the LHS footrest plate as heat-sink, I increased the effectiveness by applying some thermal paste (CPU cooler paste) on its contact patch.
 
OP
OP
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Cambridge U.K
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1994 st 1100
Hi all
quick update have been cleaning connectors and have ordered alternator from partziller .Over ?100 cheaper including delivery than U.K.
Should i think of changing rectifier as well tested ok.
Have seen one on Aliexpress $35 what do you think worth a try ?
 
Joined
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Hi all
quick update have been cleaning connectors and have ordered alternator from partziller .Over ?100 cheaper including delivery than U.K.
Should i think of changing rectifier as well tested ok.
Have seen one on Aliexpress $35 what do you think worth a try ?
I wouldn't replace it if it tests OK. Don't know about the Chinese knock off though. I'd be leery. Wait until you have the new stator in and see what your voltage reads.
 

ST1100Y

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I wouldn't replace it if it tests OK. Don't know about the Chinese knock off though. I'd be leery.
+1...
But even if the VRR seems OK when checked with the multimeter, I'd look for signs of overheating in the "putty" around the prongs; if the resin shows signs of having melted/boiled, I'd expect a high risk of failure in the near future... silicone semiconductors don't appreciate being cooked... (IIRC are 120?C/248?C core-temp the death-limit...)
Chinese mock-offs... dunno... too high chances of "buy cheap, buy twice..."...
I'd check eBay, lots of good, used parts floating there.
 
OP
OP
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Feb 7, 2015
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Location
Cambridge U.K
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1994 st 1100
Hi all,
Well that went well and to be honest hardest part was trying to torque the bolts ,
you seem to need every attachment possible especially for the four drive shaft nuts.
My new problem is the clutch seems to now slip under acceleration in a high gear
I have read on here that it might be the oil .I used motul 5000 10 w 40 or the springs
any ideas
 
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