Pressing the GS500 stem into the replacement fork

[Dawn Light]

This is for the Upgrades/Front Fork wiki section

One of the ways to replace a fork is to replace the stem on that fork with the GS500 stem. I want more information about that.

1. Can any stem be pressed out of it's fork? I understand there may be a problem with welded stems.
2. Can the GS500 stem be pressed into any fork that's hole isn't smaller?
3. Can it be pressed in to a fork that has a much bigger hole?

[hmmmnz]

1 any stem can be pressed out, the gs and othe steel ones are infact easier, you just have to grind the weld that holds them in and then you can wack them out with a wooden mallet.
a alumium bottom yoke can be alot harder, i had to use a 20 ton press and still couldn't get it out, i had to cut a groove on the inside of the stem before i could get it to budge
questions 2 &3 are the same question but worded diferently..... no not every stem can be pressed in as they are all different sizes, the rgv (i think the vj21 has a steel bottom yoke) and you can press in the gs yoke, certain model bandits are the same as well
but the gsxr has a aluminium yoke and has a wider stem so a spacer has to be made for the gs stem to be pressed into, or a custom stem has to be made to fit the bottom yokebut still be the same width and lenth as the gs.
hope that helps ya
heres a picture of the gsxr bottom yoke with the cut stem

,

[hmmmnz]

ok this is another one relating to the front fork thing
the gpz750(ill have to confirm years for you) have the same width forks as the gs, so will slide in to the gs yokes without having to change headlights yokes ect, the only issues with this is you have to use the gpz brakes but you can't use the gpz wheel as its a wider wheel, you have to use the gs wheel with smaller discs (220mm discs?? ill have to do a measure for you)
the good thing about these forks is the have the quacker anti dive system which uses the brakes to move a plunger in the forks thus restricting the flow of oil while braking hence stopping it dive, the down side to this is when you are braking bumps are alot more pronounced../. {';'}

[JamesG]

Have you tried putting the GPz front end together yet? While the fork tubes may be the same diameter, very rarely will the triple clamps (what you are calling "yokes") be the correct offset and spacing to allow the doaner axle, wheel, and spacers fit properly.

And I don't understand what you mean by the Kawasaki wheel won't fit. Why not?
Anti-dive won't be much help on your bike. It was a fad back in the '80s. Its also probably tuned for that big 500 lb. GPz not your little GS. Also why are you replacing the forks with these?

[Dawn Light]

More about the spacer... What material? What if the difference is very small? I've read something about aluminun foil...

about the gpz750 thing... so this is another way to replace a fork that i hadn't known about. will any pipes of the same width (what is it)  fit?

very rarely will the triple clamps (what you are calling "yokes") be the correct offset and spacing to allow the doaner axle, wheel, and spacers fit properly.

What does the offset have to do with this?

[hmmmnz]

Have you tried putting the GPz front end together yet? While the fork tubes may be the same diameter, very rarely will the triple clamps (what you are calling "yokes") be the correct offset and spacing to allow the doaner axle, wheel, and spacers fit properly.

And I don't understand what you mean by the Kawasaki wheel won't fit. Why not?
Anti-dive won't be much help on your bike. It was a fad back in the '80s. Its also probably tuned for that big 500 lb. GPz not your little GS. Also why are you replacing the forks with these?

did you not read it at all??
you are still useing the gs yokes(triple clamps if you like) so off set is exactly the same as it was before,
you cant use the kawazaki wheel because it is wider than the gs wheel, and since we are using the gs yokes the distance is exactlly the same width apart as what it was with with the gs fork tubes.
as for the anti dive it is adjustable and can be tuned for any weight you desire.
hope that clears it up for you

[hmmmnz]

dawn light im gunna use the old bottom peice from the gsxr yoke and cut it to the correct lenth, i will chuck it on the lathe and mill the inside till the gs stem can be pressed in side it, then i will weld a couple of tacks to keep it in place inside the spacer. then press the whole thing back into the gsxr yoke. so i will have a gsxr yoke with the gs stem poking through and being the correct lenth and width.
the gsxr i have is considerbly larger than the gs's one so the tape wont work in this instance but im sure with other models it'll be closer, and tape would work fine,

[Dawn Light]

im gunna use the old bottom peice from the gsxr yoke and cut it to the correct lenth

What do you mean by the correct length? Aren't you gonna cut everything apart from what's pressed in?

the gsxr i have is considerbly larger than the gs's one so the tape wont work in this instance but im sure with other models it'll be closer, and tape would work fine

What tape exactly? How do you put it? Doesn't it slip when pressing it?

[sledge]

Dawnlight?
The answers to your 3 questions are all...."it depends"....As I suggested in a earlier post, take the parts to a Engineering/machine shop. Explain exactly what you want and get them to explain face to face what can be done and how. With respect the questions that you ask suggest to me you have little understanding of whats actually involved despite some excellent input from James and Hmmmnz. Remember this is part of the steering arrangement and it must be done correctly, if it fails in use you could be seriously hurt.

[Dawn Light]

I'm not planning on the fork replacement anymore because my ride was totalled in a crash. I'm doing research for the Front Fork wiki section. Anyway I won't go deeper into this so i have all the information i want.

[hmmmnz]

ok dawn, there are a few variables with the yokes.
1 the distance apart the fork holes are in the yoke
2 the size of the fork holes, eg. gs =37mm gsxr= 42mm usd usually around 52mm gpz 37mm
3 the distance vertically from the center of the fork ho to the center of the stem hole (offset)
4 the width of the stem, at the fork hole, and along the lenth of the stem
5 the lenth of the stem (this bit sits inside the tube on the front of the bike)
ok got that??
if the offset is different from the standard it will change the steering dinamics of the bike (not very often are they the same between bikes)
so changing the yokes will change the steering dynamics unless the off set is exactly the same, the gsxr off set is smaller than the gs.
the lenth of the stem is important but not as important as the width, because you can make up spacers to fit above the bottom yoke and below the top yoke to make up the extra lenth,
but if the stem width is too wide you'll have to try and get bearings that will fit both the stem and the head set tube,
now for the cutting ect. i am using the gs stem because we know its the correct lenth and width, yep?
but in order for me to use the stem i have to 1stly press it from the gs yoke, then i have to press the gsxr or donor yoke stem from its yoke,
because the width of the donor stem is wider than the gs stem at the base i cant just put the gs one in as it would fall out, so i have to make a collar from the original donor stem machine it untill the gs just slides inside it, once its inside i can the tach it to the inside of the collar,
now i have one stem that is the correct lenth and width but will also fit the donor yokes.
tyhen i will press in the stem into those yoke and,,, wa lar. i can now mount my new yokes to the gs letting me use the donor forks and donor wheel and beasty brakes.
sorted
let me know if you need some more clarifacation, sweet as

[Dawn Light]

hmmmnz, Why don't we make a hole in the donor's stem while it's in the yoke, and then press the GS stem into that?

[hmmmnz]

you could do that, i just didn't measure and assumed the gs stem would fit
basically i fu(ked up, lol,
but in saying that, you have to machine the inside of the other stem, you can't have a yoke spinning around on a lathe so you need to pull it out, unless yo have the perfect size drill bit a good drill press and a good clamp(vice) thats the only way you'll get away with out removing the stem,
but you still have to cut the stem flush against the top of the bottom yoke... harder than it sounds

[sledge]

Dawnlight?
Its not difficult and there are recognised engineering practises and techniques that will allow a GS stem to be fitted to just about any yoke, but it must be done accurately without compromising strength or reliablity, any other way means it will be distored and affect alignment or in time it will just fall apart. I understand your last comment. You are proposing to cut the stem off flush with the bottom yoke and bore it out to form a sleeve into which the undersize GS stem will press into. Nice idea but very difficult in practice and in my view impossible for the amature who is not experienced in machine work. The yolk would have to be held in a 4 jaw chuck and aligned in the vertical and horizontal to 0.01mm, the stem parted off and the remnant bored out, you just cant drill it out and expect to get the required accuracy, Have you got a 35mm drill, or more importantly a way of holding and turning it, then making sure its perfectly aligned ? You could drill it close, then ream it through if you have the right size tooling and got the alignment bang on in the 4-jaw but its a complicated way. Its far easier to sleeve the stem if its undersize or turn it down if its oversize to suit the yoke, all easy 3 jaw work with one set-up, but unless you get the sizes and tolerances correct and I mean to 0.01mm what will stop the sleeve pressing out of the yoke when you try to press the stem in? Thats where the turning and fitting skills come in. The vertical axis of the stem must be at exactly 90deg to the horizontal centerline of the yoke when viewed from the front, if its not the steering and handling will all be to chicken. Some things to bear in mind, the yoke and stem must be very tight when together, an intereference fit is required, just like the original, if it took 20t to press it out it needs 20t to press it back in, Suzuki did it that way for a reason and any other method such as trying to shim it out with tape/foil etc wont last, its suicide, it will over time loosen off and you cant take chances with steering components. You cant weld aluminium to steel, if I knew a way I would a very rich man, you could use loctite or similar products but it will be nowhere near as strong as a weld. You could use a combination of Loctite and a knurl to gain intereference but again it wouldnt be as strong as the original fit.  Accuracy is vital, if the forks are 0.1mm out at the top  they could could be 10mm out at the bottom and the bike will handle like a tennis-ball, anti-dive and twin disc brakes are worthless if everytime you use them the bike pulls to one side or the whole front end shudders. I really and honestly do give you credit for your way of thinking, your approach to the problems and for what you are trying to achieve but its obvious you dont have the Engineering skills (yet) required to tackle this job properly or advise others how via a Wiki so l say again,  find a local machine shop, discuss what you are proposing to do, listen to the advice and comments, take it on board and go from there.

[hmmmnz]

i'd have to agree with sledge, in most points he has made, but personally i think that the gpx is the easiest and safest dwin disc change over as there is no changing the yokes so allthe original suzuki stem and handling will be basically the same, although i won't be doing it, not because i don't want to its just i have other forks, with which ill have to do the sleeve method, unfortuatly ill have to get some one to do all my machining work as i don't have a lathe over here like i did back home in nz(it galls me that im gunna have to pay some one for something i could do easily, but this is one mod that you don't want to bodge)

[werase643]

I installed a set of CBR600 hurricane(87-90) directly into a set of GS tripples....in 94....i don't think i changed a thing.....