front end/fork replacement - some questions, measurements

[Dawn Light]

(EDIT -  GO HERE!!! http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/FrontForks)

the stem has two bearings on it... which hold the chassis neck(can i call it that?) from each end. so any bike that uses the same STEERING BEARINGS as the GS500, should be able to contribute it's front end to it. a little shortening and spacers (like what you did dgyver with the katana) will be required. am i right?

if what i said is true, then it can help create a list of various front ends that can be easily modified to fit the GS (good for the wiki (and me( )))

that will be done by somehow cross referencing using a bearing retailer's database.

a link to dgyver's GSX 750/600 Katana front end replacement: http://gstwins.com/gsboard/index.php?topic=13673.0

[dgyver]

The stem is the same for all years.

There is not a single diameter of the stem. It varies on the stem itself in about 4 places...where it presses into the lower clamp, at the bottom bearing, upper bearing and at the upper clamp.

[Dawn Light]

i've checked the parts fiche. next to the bearings' catalogue number there are also dimensions:

lower bearing (30X55X17)
upper bearing (25X47X15)

did a little research:

i am sure someone will correct me if i am wrong, so this is how i figure it out: lower: d=30, D=55, B=17 upper: d=25, D=47, B=15 T=b=B here is some information (most of which i did not understand) about this type of bearing: Taper Roller Bearing consist of four interdependent components: the cone, or inner ring; the cup, or outer ring; the tapered rollers, or rolling elements; and the cage, or roller retainer. The taper angles allow the bearing to handle a combination of radial and thrust loads. The steeper the cup angle, the greater the ability of the bearing to handle thrust loads. The taper roller bearing has the ability to carry combinations of large radial and thrust loads or to carry thrust load only. Because of the difference between the inner and outer raceway contact angles, there is a force component, which drives the tapered rollers against the guide flange

[Dawn Light]

it works!
i ran a search for "30x55x17" in an internet retailer that sells steering bearings
this is the website http://www.z1enterprises.com
i got four different sets of bearings:

25x47x15	30x55x17
26x47x15	30x55x17
26x47x15	30x55x17
28x52x16.5	30x55x17

the larger of the couple is the lower bearing.

now when i go in to the product details of each of these, i can see a list of aaaaalll the motorcycles that use them.
the last one is pretty much out of the question because only big Kawasakis use it.

i think i am one step closer to this list of "possible GS500 replacement front ends, from which i can choose".

now if i think about it further, the bearing dimensions is only one of the prerequesits. another that i can think of is that the bearings must be at least 131mm apart, like dgyver measured. another thing i may want is for the original GS500 front wheel to fit.

[dgyver]

Looks like you have a good start on finding what else fits. The 131mm distance does not have to be exact. There will be some clearance for the bearing to slide on the stem when it is tightened down.

You can swap stems, if your GS has a pressed in stem. If it is welded it would be a lot more work. The last Kat front end I installed had a welded stem. I was able to grind out the weld, press out the stem, mill the lower clamp flat and press in a GS stem. I have not wrote the addendum to my fork swap thread with this info yet but I have the pics.

Note that these both have steel lower clamps. Going from a steel clamp to an aluminum clamp (like a GSXR) may be a problem. I measured them to be about .5mm larger in diameter so pressing in a GS stem would not work unless the stem was welded to add some material. Some of the newer GSXR's may be different.

Instead, I had the GSXR stem turned to fit in the GS. This way it is a perfect fit without requiring spacers or different bearings. Plus the stearing lock is aligned properly where with spacers it is not. I did this with 99 GSXR750 forks. I have a drawing of what I had done if needed.

A note about getting a stem turned is you will need a lathe that cuts metric threads. The preload nut uses 25x1.0 threads and a commerical die is not made.

[dgyver]

......another thing i may want is for the original GS500 front wheel to fit.

You will be very limited to the forks which share the same axle size (14 or 15mm, I do not recall) and spacing for the rotors. 89-97 Katana are the only one I know of. The 98+ Kats may, they do share the same axle but I think they use a 3.5" wheel.

Best advise is to plan to buy everything for that front end.

[Dawn Light]

You can swap stems, if your GS has a pressed in stem. If it is welded it would be a lot more work.

so then i want to know the diameter of the stem along where it is pressed into the lower triple. in a bike that uses that same diameter, a swap can be made. what about the way the upper clamp holds the stem - that needs to be identical too. is it usually a simple screw, like in the GS? if it is, should be no problem doing the swap. only thing i can think of is that the original distance between the clamps will change, which may effect any brackets you have there on the forks.

[dgyver]

I will have to look for my original sketches with those dimensions later this weekend.

The top clamp will have to fit as well but a bushing can be made for this since the GS stem is probably going to be smaller than the donor.

[Dawn Light]

The top clamp will have to fit as well but a bushing can be made for this since the GS stem is probably going to be smaller than the donor.

what is a bushing?

[dgyver]

A bushing is just a filler between a shaft and a hole. Kind of functions like a washer but looks like a short piece of pipe. Does that make sense?

[Dawn Light]

is it possible to shorten the bearings' "shoulders" (like dgyver did) with all steering stems? are they all built like that?

[hmmmnz]

hey guys im in the middle of a front end change over as well i have every thing ready, i have pressed the stem out of my new bottom yoke and am gunns use the gs stem,
but i think the gs stem is a bit narrow for my bottom yoke so ill have to make up a bush for the gs stem to sit in. do you guys happen to know the width of the gs stem at the bottom where it sits in the gs bottom yoke??
im not sure what my forks are off, i got told they were off a bandit, but the yokes dont match any bandits, i though gsx but again can't find a match(got similar but not exactly)
managed to get nissin 4 pot calipers to fit, im using a gsxr rim, gsx master cylinder and splitter, so apart from the stem issue it'll just be the clocks that i have to sort out

[Dawn Light]

does anyone have these measurements? i want them since i want to keep my original wheel. i hope it wasn't bent in the accident.

[werase643]

piece #6 0.865- 0.870 ish
length #4 8.25
#4 diameter   0.585

do you not have a bike to measure?

[Dawn Light]

Thanks werase643. Are these imperial or metric? I crashed into a car. Don't want to take things apart before I get the money from his insurance.

[dgyver]

so then i want to know the diameter of the stem along where it is pressed into the lower triple.

Here are the diameters of the stems I measured when I did the stem swap.
This is where the stem presses into the lower triple clamp.

GS: 30.15mm
GSXR 30.33mm

[Dawn Light]

thanks dgyver

[werase643]

that would be ASE....imperial.....INCH