SWINGARM SWAP

[ThAzKat]

I have a 93 gsx750f that I want to change the swingarm. I have heard that the gsxr 1100 will work with no mods. How much truth is there to that and what is possible? I would like to run a 180 on my bike. I will eventually change the power plant but I wanted to make sure the swingarm will work first.

[Waltari]

Whoever told you it was a straight swap with no mods was most definitely incorrect. The main problem lies in the lower subframe rails.

In order to accomodate the larger rear wheels/tires, most swingarm fair out failrly quickly after the shock. That portion of the swingarm will make contact with the lower subframe rails and not allow the swingarm to go through the range of motion.

You can simply cut those rails and weld in new rails higher up, but since the katana footpegs are attched to them, you'll also nee to fabricate some kind of rearsets/new fottpeg mounts as they would be too high it you just left them on your relocated subframe rails.

Another consideration is the pivot bolt. Katanas use a very small pivot bole (cant; recall the exact size but it's around a 15mm) Most larger cc sportbike use something in the 18mm-20mm range. Now about the GSXR swingarm...basically, the same arm was used on many of the GSXR1100s, the RF900s, and the Bandit 1200s. I used the RF900 arm on my bike and made the choice to make new bushing that would insert into the needle bearings on the RF900 arm thus allowing me to use the stock katan pivot bolt (and not have to drill out the frame for the larger RF900 bolt.

Also, believe it or not, the above mentioned swingarms are actually narrower at the pivot tube than the stock katana pivot so you also need to aluminum or stainless spacers to make up the difference.

Next comes the dogbones and linkages. Because of the different dimensions, if you don't want to cut and relocated the shock mounts on the frame itself, you'll need a custom lower linkage and custom offset dogbones to make everything align correctly.

Another foerm memeber of katanaplanet.com had been doing zx6r swingarm swaps but they required almost the exact same amount of cutting welding and fabrication.

My advice, it you want a straight bolt on swap, you'll need to contact a good fabricatpr and swingarm company like JMC and have an arm custom made that will allow for the size rear rim you want to run and be narrow enough toward the front to clear the lower subframe rails. I would guess, an arm that met those requirements would need to be a bit longer and might wind up looking like a drag racing swingarm.

There you go...my .02 for what it s worth

[ThAzKat]

Thank you very much. I thought the lower frame was going to be a problem area from the get go. My original idea saw that the chain might hit that section of frame with the wider tire. I have some rearsets that I know will work on the bike. All the spacers you have mentioned are no big deal. The moving of the shock mounts, up or down or do I have to custom make the top shock bracket? What is the measurement from inside to inside of the arm at the rear axle? I have this mad idea that I want the look of the bike to be stock as possible from the side.

Could you e-mail me some pic's of your bike, your avatar does no justice.

Thank you for all the information and it looks like I need to dig into this project just as soon as I get some more numbers.
Thom

[Waltari]

The Spacers you need


Ok..first off...let me apologize up front to everyone for the dated pictures. I'll try and get my lazy a@@ out to take some new shots so you don't keep seeing the same photos. That said...here is a couple of images show Thazkat how it panned out.

[ThAzKat]

Looking real good so far, can not wait for the finished project. What is your plan for unvailing the FRANKINKAT?

[ThAzKat]

[quote="Waltari"]You can simply cut those rails and weld in new rails higher up, but since the katana footpegs are attched to them, you'll also nee to fabricate some kind of rearsets/new fottpeg mounts as they would be too high it you just left them on your relocated subframe rails.


What rearsets did you go with and are you comfortable with them? I do have a shop I can make the rearsets at and machine the spacers if need be. I also checked on KP and asked the same question about the swingarm swap, I was told the 92 and older gsxr 1100 arm would work, what is your take on that? If I may, why did you go with the R1 frontend and not a busa or gsxr Frontend? I would think the busa would be better set up for a heavier bike like the Kat.
Thom

[Waltari]

What rearsets did you go with and are you comfortable with them? I do have a shop I can make the rearsets at and machine the spacers if need be. I also checked on KP and asked the same question about the swingarm swap, I was told the 92 and older gsxr 1100 arm would work, what is your take on that? If I may, why did you go with the R1 frontend and not a busa or gsxr Frontend? I would think the busa would be better set up for a heavier bike like the Kat.
Thom

I wound up using rearsets froma cbr900rr simply because I had them laying in the garage. Frogger, a former memeber of KP had been doing similar rearend conversions and I think he used zx6r sets on one and R1 rearsets on another. Honestly, since you need to weld in new mounts ofr the rearsets to attach to, you can pretty much use whatever you want and mount them to your own level of comfort. Be aware though that you likely have to cobble together linakges to make everything work together.

The info on the gsxr swingarm is correct in the sense that, the year gsxr arm you mentioned is basically the exact same swingarm as the bandit 1200 and the rf900. Same rules still apply though, the gsxr arm wont clear the lower subframe rails either and will have all the same installation considerations as the other two arms.

As for the R1 front end, I actually had a 92 gsxr750 frontend with six pot calipers from a 2000 hayabusa. I had been talking to a guy that had done a R1 conversion on his GSXR using the stock gsxr triples as they had they same spacing a certain years R1. Primarily, I liked the look of them better and honestly, the newer R1 brake are killer! Your right though, busa forks would likely be sprung better for the kat as they are but you'd have to figure out what triple you'd us as the busa uses different bearings and I'm pretty sure it uses a different sized steering stem.

[Haggisman]

That thing is lookin awesome!!

Can't wait to see it when it is all finished

[ThAzKat]

Waltari, I have been meaning to ask, do you have the brake hardware for the rf900 swingarm?
I am starting to get my parts together for the swap. I have made a list and slowly buying the parts I need.

[Waltari]

Sorry Thaz...only have the arm, no brake hardware. I did find the bushings that I used for measurements that I could send along if you need them.

[Black_peter]

Waltari thats an RF nose??

[Waltari]

Waltari thats an RF nose??

At one point in it's life Since all I'm waiting on is finishing the bodywork and paint, I figured I'd better get off my a@@ and start doing some work again. Here's a couple images fom today...bodywork has moved inside my office/studio and is getting the last bits of plastic welding and fitting of the headlights. I'm reusing the old lights from the setup I had when I was running it without any fairings. I'm cutting one new hole in the nose for one and the other will go belowe the fairing on a seperate bracket. Just a quick note, in the photos the light is pushed through the opening a little, when it's done it will sit pretty much flush.





This shows the transition I'm doing between the old Kat fairings and the RF upper...

[ThAzKat]

Waltari, you will have to PM me on info on plastic welding, I can weld but have no idea how to plastic weld.

Looking awesome and I am jealous of you. I am far from even starting my KatBusa project.

[Black_peter]

The transition doesn't look that bad,
was it? Or did you make it look good

I'm attemping to make a ABS welder, the melting point of ABS is 200F suposedly.
I think that info was in error and it is 200C
450F ~ I have access to lots of temp control items.

Waltari, does that temp sound right?
I'd like to make mine work with a pressure pad.
I think the chance of distortion is less likely.

[Waltari]

Not sure on the exact temp, but you can plastic weld with an 80watt soldering iron.

The transition wasn't horrible but took some doing. Filled the upper vents on the stock fairings, created new pieces to transition the upper part of the RF fairing into the top of the kat fairings, filled the healdight hole and still blending the lower part of the RF fairing into the insides of the stock fairings. Definitely not a simple cut it off and weld the new on process.