ST1100 40 amp alternator removal

mick hill

mick hill

Mick
Joined
May 7, 2012
Messages
6
Location
United Kingdom
Bike
St1100
I'm researching how to remove my cracked alternator from my 99 ST1100, the swing arm out and fuel tank out etc isn't the issue, the bit I don't understand in the Haynes manual is how to keep the gear driven end of the alternator in the engine and just remove the alternator,it really doesn't make much sense to me.
I have a very good second hand alternator to fit .
I have seen in a you tube video a guy just removing the alternator and the gear seems to have stayed put in the engine. I don't fancy going down the Lewis pin method.

Hopefully many of you guys have done this and can assist me.
Just done the cam belt change today and replaced my radiator, with 116000 miles on the old girl I thought it was wise to change the belt.
Thanks in advance

Mick
 
Hmm.. Remove 3 bolts holding assembly in, then separate alternator from gear. There is nothing mechanical holding it in place after that. Just friction forces. If the alternator is stubborn it may require some coercing.

Note that if you happen to turn the gear housing during the removal process, as in rotate it while turning the alternator assembly, you may end up with an oil leak from the first o-ring. O-rings that have conformed to a single position usually do not like to be disturbed.
 
John OoSTerhuis said:
Buy the Honda Service Manual and keep the Haynes for the occasional picture. Do not sync the carbs using the Haynes. JMHO

John
Click to expand...

In decreasing order of informative: Honda Factory Manual, Clymer Manual............................................Haynes Manual. Bound to be something else but if so, they aren't consistent across model lines.
 
Remove the three bolts, then rotate the alternator and then re-install just one bolt to keep alternator shaft assembly in place while you remove just the alternator.

Worked for me when I swapped-in the new Chinese replacement alternator.

And BTW, I wasn't the person who discovered those $142 Chinese alternators, but I may have been the first Forum member that threw the dice and bought one.
 
Jim Van said:
Remove the three bolts, then rotate the alternator and then re-install just one bolt to keep alternator shaft assembly in place while you remove just the alternator.

Worked for me when I swapped-in the new Chinese replacement alternator.

And BTW, I wasn't the person who discovered those $142 Chinese alternators, but I may have been the first Forum member that threw the dice and bought one.
Click to expand...
Ware can I purchase one of those Chinese alternators
 
Hi all.

Sorry to resurrect the thread but I am having trouble fitting my replacement alternator. I have it in and aligned with the gear drive bit that fits on the front, but I cannot get that to mesh with the internal gear of the engine. Any ideas? Unfortunately the drive bit had to come out with the old alternator due to corrosion issues.

Thanks in advance!
 
Jim Van said:
Remove the three bolts, then rotate the alternator and then re-install just one bolt to keep alternator shaft assembly in place while you remove just the alternator.

Worked for me when I swapped-in the new Chinese replacement alternator.

And BTW, I wasn't the person who discovered those $142 Chinese alternators, but I may have been the first Forum member that threw the dice and bought one.
Click to expand...

I put in a new Chinese 40 amp when I did my upgrade from the 28 amp a few years ago. Actually got it through Walmart.com for $140 too. 10,000 miles later and still happily charging away! I do have a used Honda 40 amp alternator that came with the backing plate it took me 6 months to find (wow, hope I never have to do that again), but I'm hoping I'll never have to use it.
 
D1now said:
Hi all.

Sorry to resurrect the thread but I am having trouble fitting my replacement alternator. I have it in and aligned with the gear drive bit that fits on the front, but I cannot get that to mesh with the internal gear of the engine. Any ideas? Unfortunately the drive bit had to come out with the old alternator due to corrosion issues.

Thanks in advance!
Click to expand...
If you took the backing plate off the motor that has the gear that would mate with the gear in the motor, you're going to have to use a "lewis pin" with a cable threaded down through the drain plug to get it to mesh with the gear in side the motor. The gear on the backing plate has two parts that is spring loaded and will not mesh together unless you hold them together with a lewis pin. Do a search for alternator up grade and you'll see what I mean. John O has a travelling upgrade tool kit that has everything in it that a guy would need to do a 40 amp upgrade, including the lewis pin tool. Contact him if you want to get it, plus he's a fountain of information and great to help out. He helped me immensely when I did my 40 amp upgrade a few years ago on my '94.
 
Ok thanks. I am in the UK, so am guessing the "travelling toolkit" is probably nowhere near me.
 
D1now said:
Ok thanks. I am in the UK, so am guessing the "travelling toolkit" is probably nowhere near me.
Click to expand...
You could make your own lewis pin out of a length of stranded picture hanging wire, some plastic tube and a cotter pin that was big enough to put in the two holes to hold the gears together. I got this picture off the web to give you an idea of what it looks like, sorry wish I could credit the pic, but I don't know who posted it as I just did a google search and this picture came up. The plastic tube is inserted from the drain plug hole up through the hole the rear of the motor that the backing plate goes in to, then the stranded picture hanging wire is threaded down through the tube with the pin locking the two gears together on the backing plate. After the plate is inserted into the engine and the gears all mesh up, the pin is pulled out through the drain hole releasing the tension on the two spring loaded gears on the backing plate. Then you bolt it up . There are better explanations available from the experts if you do a search on the stowners and striders web pages that explain it better than I can. I think there are even detailed instruction of how to do it, but you'll need to search for them. This Utube vid shows how it works. Good luck.
 

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:thumb:
It can be done without a clevis pin, I did it back in 2008 on my ST1100. I saved/recorded the details but they are on MSoffice and I don't think It will load on this forum, but I'll try it.
Update when I try to attach a file the forum is looking for "All supporting types" so it won't load. Any suggestions?

:cool:
 
Last edited:
BillyBob, could you open the document in Office (presumably Word) and then save it as a PDF?
 
OK, I've copied and pasted the text.
And tried withb the photos at the end.

Hound, I'll try.

HONDA ST1100 ALTERNATOR/GENERATOR DRIVE UNIT FITTING.​

This is how to refit the alternator drive unit to the engine without using any method that involves holding the split drive gear with a 6mm pin etc.

Locate the drive unit with the three long pins that hold the alternator and the body of the drive unit to the rear of the engine case.

(Photo in original -!st)

Put the bike in top gear by rocking the output shaft while operating the gear lever. Refit the prop shaft onto the output shaft of the gearbox and prevent it rotation by jamming something like a screwdriver through the universal joint against the brake pipe bracket.

(another photo -2nd)

Have at least one short m8 bolt to hand and returning to the drive unit insert the 12mm hex to half-inch drive socket into the drive unit shaft splines with a 4inch extension bar and ratchet driver. From the left-hand side of the bike press on the drive unit around its centre from below the shaft in the direction of the engine, while winding up the ratchet drive in a clock-wise direction with the left hand until the crank gear and gearbox stops rotating and you will find the split gear will index and the drive unit pop into position. Keep it in place with the right hand while one long bolt is withdrawn and a short bolt screwed in its place to hold the unit up against the engine case. The other two long bolts can then be removed.

(last photo -3rd)


©lancepar 2008

1633186966821.png
1633187011583.png
1633187059643.png

Then pop the Alternator in after removing the short bolt.

:cool:
 
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Thanks Hound,
Here is a .pdf
Hope it works.
:cool:
 

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  • _ALTERNATOR drive unit refitting.pdf
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D1now said:
... I cannot get that to mesh with the internal gear of the engine. Any ideas?
Click to expand...
I used a piece of wood, inserted into the bore where the alternator shaft would go in, as "handle" to tweak the spring loaded gears till they meshed with the generator drive gear...
No Lewis Pin, no removal of oil pan, nothing... didn't even drain the oil from the '94 ST while installing the Chinese 40A unit ... a gentle twist on the wooden stick and the gear went right in...
 
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