GSXR Inverted Fork Install

[tbone1980]

I am taking the plunge and installing a 1999 GSXR 750 inverted fork on my 1982 XS Special. I will be posting pictures and specific specs of how I am doing it. My hope is to get more info out there for others to use. I have spent a lot of time researching this project and have had a hard time compiling all the necessary info in one place. My goal is to install the front end while still utilizing the original 19" wire wheel and using the gsxr dual disc brake setup. The reason I picked a 1999 GSXR front end was for many reasons. The first reason is there are a good amount of them on ebay for pretty cheap ($150-$300). The second reason is that these forks do not have radial brakes. The reason I didn't want the radial brakes is that they don't allow the same amount of space for me to use my stock 19" rim with the two discs. At least that is my thought processes so far. I am hoping that at the end of this journey I can have a great write up and pictures to help anyone else out there that wants to do this.

 

[Cafe-Dave]

Good call on a conventional mount caliper. You'll be able to get the caliper spaced in correctly.

Measure (with calipers) the inside brake face to inside brake face of the GSXR, that's your goal now. I'm going to guess that the GSXR wheel has a 90mm brake mounting face to brake mounting face. The XS650 wheel is probably 86mm

The brake disc is your next problem. Plenty of options.

 

[tbone1980]

It certainly will be interesting figuring out how to use the stock 19" wheel with dual disc that work with the stock gsxr brakes. I am hoping that whatever needs to be done I can replicate and make available for others that want to do the same exact swap. The whole goal for me is to almost make a kit of sorts that any person can use with the same setup and make it easy. We will see!

 

[Liftedzuki]

Why not a real nice single brake setup?

I'm looking into a GSXR fork setup (03 or older non radial) for my 75 xs. I want to run the factory 19" wheel as well, to match my rear 18".

 

[tbone1980]

Well I just received my 1999 GSXR 750 forks and calipers yesterday. I am hoping to start the swap process this weekend. As far as the one caliper or two question I will have to see how the spacing looks before I make a decision which way to go. One of the downsides to the dual disc is that is does hide the nice look of the spokes. So I guess it is still up in the air. I will try for the dual setup first and then maybe swap to a single after I get my hands dirty. I still need to find rotors that would work. Anyone have suggestions on that? Also I am wondering about the axle and what mods I will have to do there. Like I said before my hope is to give very specific information on what I end up using and how I used them and also if a custom piece is needed making a kit to help others out.

 

[Liftedzuki]

Should be able to use the GSXR caliper and XS rotor from what I read.

 

[RpNSht]

can you do a huge favor and document this process? im really interested in this and am planning on doing this on a future build thanks dude!

 

[tbone1980]

Lifted = Thank you I will try it out. I just need to get a second disc for the other side. Anyone have a spare one for a 82 special hanging around?

RpnSht = I will be documenting the whole thing so keep posted.

 

[Liftedzuki]

Good to hear, I will also be tackling this end of the month I will be ordering the front end.

I will take pics as well.. I'm not sure on radial vs non radial?

From what I understand, get new bearings, remove some material (7-8mm off the bottom bearing race, as the GSXR stem is shorter than the XS650) then drill the top triples or buy a new top triple for bar risers (I want to run my pro taper 7/8" bars for a tracker hybrid look)

Then just worry about the axle/tire/brake combo.

 

[tbone1980]

From what I read the non-radial brakes are easier to work with as far as spacing goes.

 

[Liftedzuki]

04 and up is radial for reference.

We have about 10 threads about this, and all lack some info the next has.

Considering 04+ radial setup as nate did this and it looks great, and seems to be the easiest.. Stock rotor+rim!!

http://www.xs650.com/forum/showthread.php?t=21958
http://www.xs650.com/forum/showthread.php?t=21958

 

[tbone1980]

Here is a picture of my bike as of today. I also just received my inverted forks and brakes from ebay. So far these parts have cost me $300. I will start actually working on this project this Friday.

 

[tbone1980]

So this past Friday I got my bike over to the shop to get ready to work on it. It was my first time using a new trailer to transport it so I was a little nervous about it but I had no issues. So pretty much we spread out our parts and went over the game plan for this swap. We will be taking the old front off this coming Friday and working on measurements. I will take a ton of pictures and post specifics as we work. Our main questions are:

-Will we be able to use the stock GSXR stem?
-Will stock XS650 rotors work with the GSXR calipers?
-What work will have to be done with the GSXR axle to get this to work?

We should have a much more clear idea after this Friday. Our goal is to come up with the easiest way for the average guy or gal in their garage to carry out this sort of swap.

Please stay tuned!

 

[tbone1980]

Can someone explain to me why there are so many different choices for the bearings to be used in my swap? This picture is from the All Balls fork conversion page and I am trying to see what exact bearings to order but I am confused as to why it lists so many options. Can someone help me with this? I want to order the bearings so that I have them for this Friday in case the GSXR stem will work. Thanks for any help you might be able to provide.

 

[cliff604]

Can someone explain to me why there are so many different choices for the bearings to be used in my swap? This picture is from the All Balls fork conversion page and I am trying to see what exact bearings to order but I am confused as to why it lists so many options. Can someone help me with this? I want to order the bearings so that I have them for this Friday in case the GSXR stem will work. Thanks for any help you might be able to provide.

I say just start the swap! I did a 2003 fork onto a 79 special and it was a peice of cake. I used the stem and tree's from the gsxr I also used the stronger hollow gsxr axle with the stock xs wheel. All you have to do is trim the lower neck and a bearing swap trim the jam nuts and your done . Brakes were a nightmere, stock rotors are to small I would have a custom rotor made if I do it again. I redrilled and older rotor 92 gsxr with a huge offset to fit the xs bolt pattern It worked but it was kinda hack. I'll try to load a photo but there are some under pic. section here under cafe without a plan I think

Good Luck

 

[tbone1980]

I will be jumping into this swap. I already have most if the parts but I am trying to order the correct bearings for the GSXR stem from all balls racing and I am having difficulty figuring out what their chart is telling me when it gives me a whole bunch of different bearing sizes. Can anyone help me with that?

 

[bergoff]

Subscribed waiting to see how it turns out.

 

[Tim of DO THE TON]

Can someone explain to me why there are so many different choices for the bearings to be used in my swap? This picture is from the All Balls fork conversion page and I am trying to see what exact bearings to order but I am confused as to why it lists so many options. Can someone help me with this? I want to order the bearings so that I have them for this Friday in case the GSXR stem will work. Thanks for any help you might be able to provide.

The only difference between those bearing sets is the height - 12, 14, 15mm. The All Balls chart just lists every possible combination of the 3 choices for upper / lower (9 total combos).

Both uppers and lowers seem to be 30mm ID and 48mm OD.

I'm in the middle of putting a GSXR front on my SR500. Just need to swap the bearings onto the stem and it should be on.

 

[Rabbidmk1]

Have two of these swaps going right now. The first is my 72 with a 2007 gsxr fork. The early bikes do not need the head tube cut to make it fit. I used 12mm upper and lower bearings. As for radial brakes, am using stock calipers with 320mm rotors and 5mm spacers to get the calipers I clear the larger than stock rotors. Now to get the wheel to mount, 06-09 gsxr fork use 25mm axles. Just measure the od of your hub and order appropriate bearings. Finally measure your center to center of the calipers to calculate axle spacers and rotor spacers. Bam your done!


Edit: when I say stock I mean stock gsxr.

 

[Liftedzuki]

I think all gsxr is 25mm almost. Or is that incorrect