Removing the steering stem from the lower triple

[Gordon in nc]

Folks, I'm thinking about mounting an XS (34mm) front end on another brand of vintage bike I have here in the shop. The only spare XS triple I have (for now) is off my parts bike and it's spent a LOT of time outside and is in pretty nasty shape.

My question is......can the steering stem be removed from the lower tree? I see a couple of things that aren't making sense to me and I will add photos if needed.....but I'm thinking somebody (5-twins?) already has photos of this stuff apart.

The two things I see on the underside that I can't figure out are.....what looks like a tapped hole for something like a set screw and inside the stem I see splines?

I can't tell much from looking at my rider and looking at the parts book doesn't help much either.

Not sure if it's even doable but if the stem was a bit shorter this thing would be a perfect fit.......but as Pink would say/sing "don't let me get me...I'm my own worst enemy"

Thanks in advance,

Gordon in NC

 

[XSLeo]

The stem is welded into the lower tree.
The hole up through the stem is a holdover from when they used a steering damper.
This was a knob on top that tightened a rod that pulled a set of plates together on the bottom. One of those plates were splined to the lower tree. One was hooked to the frame.
To remove the stem you grind the weld out then press the stem out.
You need to do the same to get the stem out of the tree from the other bike.
Once you have both stems removed, you just need to fit the other stem to the XS lower.
You may need to enlarge the hole in XS lower or turn down the other stem or build a shim to fit the parts together.
Once you get the other stem in the XS lower weld around the bottom as they were.
Leo

 

[Gordon in nc]

Thanks for the reply Leo. Makes sense, thanks for the explanation.

I'm in the process ( if the fellow will PM me back) of picking up a couple of good trees but in the meantime I can experiment with this ratty one.

Am I looking at a washer covering the end of the stem and the weld?

This thing is such a good fit if I can just...remove the stem without damaging the lower, cut the stem to length and re-weld it back.....it should be a perfect fit into the different frame.

Gordon in NC

 

[XSLeo]

It might be but I don't think so. I think that's the end of the stem.
If you want to shorten the stem do it at the top. There is a stop ring on the stem and above that the stem is the right size for the bearings. Just above the bearings it starts to taper. If you cut off the bottom you might get up on the taper and the bearings will be loose.
A good machine shop should be able to turn that tree with the stem on a lathe. Take along the other tree so they can turn the upper end so the bearing area matches the height. Then thread it father down and cut them to the same length.
Leo

 

[Gordon in nc]

Okay, I'm beginning to see the light.

I chopped it up enough to see what's going on.......well, kinda. I still haven't found a weld but I got tired of putting my band saw blade back on so I gave up for a bit.

I did get the lower race off and now I see what you were talking about. I had assumed the larger end of the stem was all the same size......but now I see that it's (larger diameter) bigger for the race and the tree.....rats.

Are you saying there is enough thickness in the stem to machine the whole top down lower?

I'm not giving up but it won't be as easy as I first thought.

Thanks for the help......Gordon in NC

 

[TwoManyXS1Bs]

Here's a procedure written by another member:

http://www.xs650.com/forum/showthread.php?t=30169

 

[Gordon in nc]

Don't ya just hate it when a person asks a question, you give him or her an answer and then you never hear back from them again???

Soooooo a quick update. The bottom of my stem didn't look like the one in the photos on the thread two many linked to.....I'm guessing mine (stock 650B) is an earlier version. I butchered that thing and now I see how it all went together....it was well worth the price of admission.

BUT.....I was searching through the site using some other search terms and ran across a reply from Tony C about adding a XS front end to one of his other bikes. What he did ( I PMed him but haven't heard back yet) was instead of messing with the XS trees/stem he lengthened the head stock.

Well I tell ya......that puts me right back in the game because it looks like a pretty simple fix. I need to add 1 1/4" to the bottom of the head stock and I'm good to go....just gota get something machined up to fill the space and that will except the bearing race. Oh and probably have to relocate the fork stop.....but none of that is rocket science.

Thanks for all the help......Gordon in NC

 

[XSLeo]

Stems have been turned as I mentioned, a few times at least. Not just on XS650 stems.
Leo

 

[Gordon in nc]

I hear ya Leo......but I like the idea of leaving the trees stock. Removing a stem that wasn't designed to be removed....doesn't make me feel warm and fuzzy. Yea, it's been done and will be done again. I just see to many things "I" could mess up.

AND........

It's has to be faster/cheaper to have a spacer machined than that stem?????????????

I have 25 or so extra frames....but only a couple of XS trees (that I just purchased off the site)

Thanks for the help and enjoy what's left of the summer.......Gordon in NC

 

[nj1639]

Gordon, I have the stem that I pulled from a set of xs750 standard forks. It's shorter in length than the 35mm xs650 stems. Yours for the asking if it fits what you're looking for.
I'd have to dig around for it......

 

[Gordon in nc]

nj,

Thanks for the kind offer. My extra trees are in the mail so I have to wait until I have them in hand to see which way I'll go with it.

I'm going to mess around with a spacer for the head stock this weekend but won't really know how well that will work until I can try a tree in there.

I'll keep your offer in mind and thank you again for it.

You gota love a hobby where people are so willing to help each other out....


Take care and enjoy what's left of the summer.

Gordon in NC

 

[Gordon in nc]

Leo, sometimes I can be as wishy-washy as a Maytag repairman.

I got my extra couple of triples (thanks to a kind fellow on the site) and over the past few days have been messing around with the swap.

I tried the spacer idea and for me and this frame it just didn't look right.....so I found the proper bit and cut the weld out on one of the lower triples and was amazed how easy that task was. Now I have a good lower without the stem and a good stem to work with.

I'm going back and forth about tapered bearings vs balls but will have that sorted soon.

The deal for the triples came with a new set of tapered rollers.

I'm using the stem I chopped out of the rusted/wasted lower as a mock up to determine just how long/short the new stem needs to be.

I'm taking the good stem to the machine shop this week and see what they say about it.

Thanks again for all the help.

Gordon in NC

 

[TwoManyXS1Bs]

Gordon. Here's some threads on tapered bearings, and prep work to allow for future removal:

http://www.xs650.com/forum/showthread.php?t=15568
http://www.xs650.com/forum/showthread.php?t=32340
http://www.xs650.com/forum/showthread.php?t=39043

 

[fredintoon]

- - - I'm going back and forth about tapered bearings vs balls but will have that sorted soon. - - - Gordon in NC

Hi Gordon,
the bearing books are wishy-washy too.
Some say a tapered roller bearing is 10 times as strong as the same size crowded ball race.
Others say it's only 7.
Either way, what's to sort, eh?
Besides, crowded ball bearings are SO 1890s tech that mfrs should be ashamed to still use it.
Betcha they'll be back to using cast iron soon.
Especially in China where air pollution is considered to be a sign of prosperity.
BTW, drill & tap the frame steering head for a grease nipple so you can refresh the lube without a teardown.