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watches you sleep.
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Discussion Starter #1
I've been researching this for a long time and found very little consistent information, little information to be confirmed and no REAL documentation of this swap. So I'm gonna do it myself. I am going to show you how to instal a 2004 Hayabusa rear end into a 1992 GSX-R 750 Slingshot frame with no machined parts required. I'm not completely done with the swap so this is a tutorial in progress so keep checking back and bear with me. We're in this together. Here's what you'll need:

-Complete GSX-R or Hayabusa rear end
-Stock slingshot swingarm pivot bolt
-Slingshot swingarm spacers



The above list will also have more added as I use the parts/tools and have confirmed its needed. Okay so The biggest part of this swap that everyone keeps talking about is how you need adapters made for the pivot bolt. What you would do is have a 20mm ID(slingshot pivot bolt) and have a 25mm OD(Hayabusa swingarm pivot hole) flanged sleeve bearing made so you can use the slingshot pivot bolt in the new swingarm.

Then I read somewhere that some people simply insert the stock slingshot pivot bolt spacers into the Hayabusa pivot bolt spacers giving the same effect as the machined pieces. I went ahead and tried the latter method and it worked perfectly.

Here you can see the two pivot bolts side by side, with the Hayabusa pivot bolt on the bottom:


From left to right you can see the slingshot spacer, the Hayabusa spacer and lastly the slingshot spacer resting snug inside the Hayabusa spacer:


This is with the spacers and slingshot bolt installed in the Hayabusa swingarm:



Here is the swingarm mounted to the slingshot frame:



Gratuitous pics:




Here is a video to show there's no excess play:

That's it for now. The next steps are(from what I've researched):

-Grind out material on left side of top shock mount for proper vertical rear shock alignment
-Shim front sprocket a little to align it with the rear sprocket

If you have any questions feel free to PM me. Thanks for viewing. :thumbsup:
 

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watches you sleep.
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Discussion Starter #2
Okay so here's a little update. As it turns out this isn't as easy as I thought it would be. You're gonna have to space the top shock mount out about 25mm from the frame for the rear shock to mount on the top and bottom without it hitting the inside of the swingarm. After that you need to get dogbones longer than the stock busa ones. I think around 140mm will work. Otherwise the swingarm gets jacked sky high in the front, enough to see a noticeably shorter wheelbase to the naked eye and that aint good. More to come.
 

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watches you sleep.
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Discussion Starter #3
I was able to get a pair of adjustable linkage off eBay for around $30. It does the job perfectly. Next I'll be having a block of aluminum machines to act as a spacer for the tope shock mount. Also I will need to shim the front sprocket out a few mm's. From what I can tell, that's it. That's all you need to do to complete the swap. I'll post up with any changes or updates.
 

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This was where I got stumped on my GSXRs. I used the spacers as well, but for some reason, it didn't seem to have much travel. I tried to figure out a way to make the top shock mount spacer without machining it, but haven't. Let us know if you find a solution.
 
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Maybe i can help with this a little :) what follows is based on doing this swap a few times myself but the exact specs can change slightly depending on the year & model of frame & arm

Dont forget to sleeve the centre bearing spacer in the busa swingarm or you will bend the slingy spindle in double quick time & the bearings wont last either

Spacing the top shock mount out is usually a result of the slightly fatter spring on the busa shock catching on the front of the swingarm shock hole, the use of a slingy shock can get you round having to do the spacer,R6 shocks have been used to good effect too but you need space under the subframe for the attached bottle, a 20mm spacer will work well & dont forget to use high tensile bolts through the bolt on type to shock mount, on frames with the welded top mount i buy a bolt on one then weld the spacer in, drill it & bolt on the new mount as usual

The stock angle of the swingarm at rest on a complete slingy is around 12 degrees from the horizontal & this is what you should aim for, the angle can be adjusted later with longer/shorter dogbones at a later date depending on what you want

You can make new dogbones to suit with simple hand tools & a drill i use steel 5mm plate as i have some :)

Most slingy or busa rear sprockets have a 1mm deep inset machined into the front face, using a new sprocket you can fit this backwards gaining you the 1mm to help with alignment, just a shim behind the front works in most cases but be sure the sprocket nut is fully on & use locktight as they are known for coming off as stock under hard use, early zx10 front sprockets fit & they have a 10mm ofset as stock which is useful if you are going really big on the rear wheel/tyre

Hope it helps :)
 

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watches you sleep.
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Discussion Starter #6
That helps a lot, thank you. I'm really not sure how I'll be able to sleeve the center bearing in the swingarm pivot bolt hole though. I figured having the 3" sleeves on each side would be enough to evenly distribute the load and not affect the pivot bolt. You're saying its not? Also I'm actually thinking on using a rear shock with a lower spring rate anyways. I have the Busa shock on there now and I think its gonna be a bit much. You're saying an R1 rear shock is small enough in diameter where I won't need to space out Tue top shock mount? Cause I'm not worried about clearance with the subframe as currently the subframe hasn't been fabricated yet and I can do whatever I want in that respect. I didn't think about just welding the top shock mount if I still need to run one after using a different rear shock, good call on that.
 
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Glad to be able to help a little mate :)

With the swingarm bearing spacer you can do it in exactly the same way as you sleeved the outer bearing sleeves, its just a matter of finding a suitable piece of tube or a spacer from something else ive used various suzuki ones in the past the length is critical but a really tight fit to the bolt isn't (check the clearances on the stock busa spacer & bolt to see what i mean)

With the shock, stick the stock slingy one in & it should not catch anywhere with no or minimal spacing to the top mount, again this does depend on the exact model of arm & frame as there are very minor differances, its really only the dia of the busa shock that causes the problem in most cases i used a zx6r shock on my last slingy it just needed a little spacing & the right length dogbones basically anything you can fit will work if you get the spring rates & damping somewhere near

A good condition busa shock is going to have quite a stiff spring rate, ive never bothered with them on the lightweight solo projects i tend to build as i'm pretty lightweight myself :)
 

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which shock linkage do you use?
I have got the correct linkage for the K1 swingarm, but not the slingshot original at the moment.

do you use the matching hayabusa/gsxr one, or the original slingshot one?

thanks, and thanks for the info about the slingshot spacers reducing the pivot size to the correct one, makes it easier. my arm is a bit too narrow at the moment, but I don't have the chain rubber for now, so hopefully it will take up the gap and get everything nice and tight.
 

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watches you sleep.
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Discussion Starter #9
For the dogbones I went ahead and bought adjustable turnbuckle style ones off eBay for about $30. That way I had more room for adjustment giving me more forgiveness in other areas for clearance. I believe the length needed to be around 140mm, which neither then slingshot nor the Busa links gave me as the were much to long.
 

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watches you sleep.
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Discussion Starter #10
And yes you need the rubber chain guard to take up the extra slack as it makes up for about 8or 10mm of the width. I didn't have to grind anything at all on Tue frame or swingarm. I was surprised but its a perfect fit. Like I said before the biggest hurdle to overcome is getting the shock to clear the hole in the swingarm. With adjustable links and a spacer 1" thick for the top shock mount, you'll be in good shape and the last step is front/rear sprocket alignment.
 

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Sorry to bring up an old thread but I'm hoping to fit my hayabusa swingarm when it arrives, I bought just the swingarm and pivot bolt from eBay and think I can manage to fit it, I just wanted to know a few nor things...

Would I need to buy a hayabusa wheel to fit or can I use the stock 92 750 wheel? Also do I need to buy the brake caliper and linkages to fit the shock bottom to the swingarm or can the stock 750 parts be used?

Any help would be great
 

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watches you sleep.
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Discussion Starter #12
Dude really the entire point of doing this swap was to use the Busa rear wheel that fits a 200mm rear tire. If all youre going for is a braced swingarm you should have just bought a newer GSXR swingarm that wouldnt need a hodge podge of parts and custom pieces made.
 

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Dude really the entire point of doing this swap was to use the Busa rear wheel that fits a 200mm rear tire. If all youre going for is a braced swingarm you should have just bought a newer GSXR swingarm that wouldnt need a hodge podge of parts and custom pieces made.
Jackstand Johnny, if your still around. I am installing this on a 91 GSXR 750 frame. I was trying to use my swingarm knuckle, but when I put the dogbones on it does not allow for the shock to move. Which knuckle did you use? Please let me know.
 

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Did you ever manage to sort this problem out CBR2GSXR?

Sent from my GT-I9505 using Tapatalk

He hasn't been around for quite some time and I highly doubt he'll return as there were some "issues" within the CF community with him.

If you haven't already ask in the "Streetfighter Help" section. You may get more responses there.

Later, Doug
 

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He hasn't been around for quite some time and I highly doubt he'll return as there were some "issues" within the CF community with him.

If you haven't already ask in the "Streetfighter Help" section. You may get more responses there.

Later, Doug
Just to clarify, Jackstand Johnny will likely not be back, but the recent post was questioning user CBR2GSXR's current status on the swingarm. No issues with CBR2GSXR.
 

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Ok thanks guys, I'll post up on there :), maybe CBR2GSXR can hold the answer

Sent from my GT-I9505 using Tapatalk
 

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I just wanted to add my recent experience on this subject which might help others.

I've got a 93 1100WP and have fitted a gen 1 Busa arm and a custom Aprilia rear wheel and brake combo.

I've used the GSXR shock (a Maxton ) the GSXR knuckle (linkage) and everything fits without the need for any machining or other spacers. The shock clears everything so no need to space it out. I need to make custom dogbones as both sets are either too long or short. I've measured 130mm between centres as a start.
Just waiting for the steel to arrive to make them, then I can get it down on its wheels to properly check the wheel sprocket alignment.
 

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