Need ST1100 Steering Stem Dimension

John OoSTerhuis

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1058
<cross-poSTing here>

A few years ago we learned that all ST1100 steering stem shafts' OD were not the same dimension. At that time the holder of the STOC ST1100/ST1300 Steering Stem Races/Bearings R&R Tool Kit bored out the ID of the race/bearing driver pipe so it would work on all ST1100 stems. The kit:
image.jpg
http://www.st-riders.net/index.php?topic=714.0

Fast forward to today. The pipe in question finally broke, having been pounded upon one too many times. The kit user kindly replaced the pipe and shipped on the kit to the next loanee who, you guessed it, had an ST with the larger diameter steering stem. He managed a workaround and put his ST back together, alerted me to the problem and sent the pipe to me to be modified. Unfortunately he didn't measure the diameter of his stem before reassembling. The STrider that replaced the old damaged pipe threw it away so its ID can't be measured. I now have the new diver pipe in hand and a local STrider who has volunteered to 'bore out' the pipe for us. How much is now the big question. So...

What are the ODs of the ST1100 steering stem's shafts? [the middle section of the stem, between the threaded top and the bottom boss the race or bearing seats on]

At the time we found out there were different ODs, IINM the STs with the larger diameter stem shafts were thought to be the later model ABS ones. I know the unmodified original pipe worked fine on my '91 non-ABS. However, the stem the driver pipe won't fit over is a 2001 non-ABS.

Can anyone help with info on this? Would be much appreciated. TIA

Regards, John
 
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ST1100Y

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I've the OEM inner/lower head-bearing race driver tool in my shop and could measure the bugger on the next w/e if that helps.
 

Uncle Phil

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John - Finally found the yoke. I don't have a set of Vernier Calipers, but it appears to be about 1 1/8" at the top, and about 1 1/4" at the lower end where the bearing goes. This is supposed to be an ABSII yoke, but no warranty is expressed or implied ... ;-)
 

ST1100Y

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And now: the tool...

P/N 07946-MB00000
Inner diameter: 30.5mm
Depth/inside length: 285mm

hope this helps
 

ST1100Y

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I'd figure the lower inner race being a 30 mil, so the tube should be only an idea larger to not "stuck" on the lower end of the stem.
The tool is made from black anodized, hardened steel, durable for quite a number of bearing replacements... a piece of steel waterpipe might serve too, as long as its business-end is kept sharp and square on a lathe or such... failing to so so might result in a ruined bearing race though...

And I always read about tricks with freezer and cooking plates... never done such, rigorous cleaning of the bearing seats (like Q-tip clean, and always check for scrapings!) followed a smear of marine lube on the mating surfaces and on they go...
Brief, precise, hard beats, placed in circular order to ensure parallel alignment, and listen for the bright ringing sound once the races have fully set...
 
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John OoSTerhuis

John OoSTerhuis

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1058
The Honda tool info is good to know, Martin. However, my driver is homemade from common steel pipe from the hardware store. I made a driver tip from a common pipe joint. Its inner diameter was ground down to match the tapered bearing inner race, leaving threads on the other end so a length of common pipe could be screwed into it to make a bearing driver tool. In the picture you can see the problem with the new pipe a recent tool kit user found. The ID of the pipe is too small. The original pipe was bored out by a user when we found out that some steering stems were thicker than others. I have asked the forums for the diameter of their stems so I can tell my friend how much to shave off the inside of the current pipe.

image.jpeg
The steering stem shaft is too thick for the ID of the diver's pipe. The tool can't go any further.

John
 
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Its been an eternity since I did mine, but I think I used a piece of PVC and cut a groove lengthwise on one side with my table saw. The groove allowed the pipe to expand just enough to fit over the stem and reach the bearing for driving. I have a '97, would that be the larger stem era? If so, that might be an alternative solution to the issue with the steel pipe.
 
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John OoSTerhuis

John OoSTerhuis

Life Is Good!
Joined
May 10, 2005
Messages
5,218
Location
Bettendorf, Iowa
Bike
1991 SSMST1100
STOC #
1058
And now: the tool...

P/N 07946-MB00000
Inner diameter: 30.5mm
Depth/inside length: 285mm

hope this helps
Martin, do you have a picture of the Honda tool? The ID of my homemade driver tip is about 32.5 mm, which leads me to believe the ID of the stem race or tapered bearing is 32mm (also the diameter of the bottom of the steering stem). The diameter of the rest of the stem's shaft is less than that. The OD of the common pipe in question is only about 33.65mm, ID of about 27.43mm. Boring out the pipe to 30mm leaves a pipe wall thickness of only 1.32mm.

John
 
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