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I recently did a USD fork conversion on my 92 Kat 1100. Had the idea from mostly two different write-ups, Wild-Bills http://katriders.com/vb/showthread.php?t=118157 , and ThAzKat http://katriders.com/vb/showthread.php?t=82769 and decided to create this one to help or inspire others after me.
The reason that I decided to do the swap started with my frustration with getting good 16 inch tires. It ended with the purchase of a parts bike, minus the frame, and the following work.
Two things to take into consideration if you want to tackle this. Basic tools will get the job done and depending on how handy you are, you can also avoid some expenses along the way.
I got my hands on both rims and a complete USD front with brakes from a 95 GSXR. I was looking for the GSXR set up for two nice reasons, 1. the bearings are the same as the 1100 Kat. and 2. the stem is the same length. That solves a lot of issues.
The first thing you will need to change is the steering stops. The stops on the Kat are on the neck. On the GSXR they are on the lower clamp on the triple. Here is a pic with one cut off. Both have to come off.
The second thing with the triple is actually making a new steering stop. Here is the mock-up.
I tapped a 5/16-18 stainless steel bolt to the lower triple. I then cut a piece of metal stock and tapped it as well so it could ride on the bolt. This allowed for the bolt to clear the bottom of the neck and still be placed at the height of the stops. Here is what it ended up as. (I may revise this)
Now comes a big decision on your part, may be determined by creativity as well. The GSXR has clip-ons that mount underneath the top triple. They will not clear the Kats fairings. One option is to buy Clip-ons like these...
But these cost $170.00 and the really nice ones cost $300.00+. Or you can make your own. Only special tool needed is a welder.
I started with 5/16th stock and traced the top triple to it so I could cut it, then bolt it to the triple.
I also reinforced the underside of the triple because I wanted to be sure that the bolts did not rip it. The bolts go all the way through. Just make sure you do not use bolts longer than 1 1/2 inch as they will interfere with the ign lock plate in the neck.
You will need to cut two 1 7/8 holes on the ends to allow for the adjusters at the top of the forks. You will weld two inch pipe to the top of the holes. I cut them at three inches, that will give you the factory ride handle height. You can cut to preference if you wish to raise the handle bars. The clip ons will attach to the top of the pipes. Note. I added a bar from one of the clip-ons to the other. That was just to make sure that they could not individually rotate if one or the other loosened. Here are the risers with the clipons attached.
Once you have this done, all you will need is a longer brake line for the front caliper. I used a stainless steel 30' line. It gives just the right length. If you are keeping the original design, the second line that goes over the fender to the left side caliper is 20 inches long.
Here is a pic of the Forks mounted with the lines installed.
I found that the front end swap lowered the bike by 1 3/4 inches. Under very heavy braking, the front fender just touched the fairing under the headlamp. So you will need to trim it.
Once you trim the fairing, you will need to remove the two body mounts under the headlight.
You will have to reposition the horn. If the screws are pointing downwards, you will need to trim. Here is what it should look like.
I used the GSXR speed sensor with the Kat cable and it seems to work just fine. Have not checked the speed against my GPS though.
I could not find a GSXR front fender, so I used one from an SRAD. It mounts on the outside of the actual mounts on the forks, but it works.
Now to the rear wheel. Only one real mod has to be done. The rear swingarm space at the axle is the same for the GSXR as it is for the Kat 1100. Just shy of 10 inches. As Wild-Bill points out in his conversion, the cush drive is the same, so you just swap it. I had all the original spacers for the GSXR.
If you use the left spacer from the Kat, you will have to shim the right side of the rim and mod the caliper strut bar. If you use the GSXR one, you will have to shim the sprocket in order to maintain chain alignment instead. I used stainless steel washers. You only need to compensate for about 1/16 of an inch, so do not shim past the center of the hub that contacts the middle of the sprocket.
I did not need to create any other spacers. But I had to modify the original caliper mount. In order to get the original caliper centered you want to trim the caliper mount. In the GSXR, there is a notch on the Swingarm that accepts the bracket. Becasue I used the original set-up I did not need that part to be there. The section pointing away fron the axle hole has to be trimmed.
You will also have to enlarge and match the bolt holes to the original caliper. I used one stainless washer at each bolt to shim the caliper just a bit. It may not be really necessary. Here is the trimmed mount installed with the original caliper. It is now upside down and with the side normally on the inside, on the outside.
I used my original rear axle and nut. all other parts necessary for mounting the wheel were from the GSXR. Because of the design of the slack adjusters, final mount is a little tight, but no need to expand the swingarm.
This was written as straight forward as I could. It is not all that challenging. It is a pretty straight forward swap.
The benefits are incredible. The bike rides like a new bike. She is very responsive and smooth to attack the turns. I have recommended this to others, and will do so again.
One ting to consider, the front will be lowered almost two inches, and the parkign lot turning radius increases. It will take a little getting used to, but it is not a major thing.
To others that may want to do this, good luck, it is pretty straight forward. Here are finished pics of the bike.
If oyu have any questions concerning info I have left out, let me know and I can answer...
The reason that I decided to do the swap started with my frustration with getting good 16 inch tires. It ended with the purchase of a parts bike, minus the frame, and the following work.
Two things to take into consideration if you want to tackle this. Basic tools will get the job done and depending on how handy you are, you can also avoid some expenses along the way.
I got my hands on both rims and a complete USD front with brakes from a 95 GSXR. I was looking for the GSXR set up for two nice reasons, 1. the bearings are the same as the 1100 Kat. and 2. the stem is the same length. That solves a lot of issues.
The first thing you will need to change is the steering stops. The stops on the Kat are on the neck. On the GSXR they are on the lower clamp on the triple. Here is a pic with one cut off. Both have to come off.
The second thing with the triple is actually making a new steering stop. Here is the mock-up.
I tapped a 5/16-18 stainless steel bolt to the lower triple. I then cut a piece of metal stock and tapped it as well so it could ride on the bolt. This allowed for the bolt to clear the bottom of the neck and still be placed at the height of the stops. Here is what it ended up as. (I may revise this)
Now comes a big decision on your part, may be determined by creativity as well. The GSXR has clip-ons that mount underneath the top triple. They will not clear the Kats fairings. One option is to buy Clip-ons like these...
But these cost $170.00 and the really nice ones cost $300.00+. Or you can make your own. Only special tool needed is a welder.
I started with 5/16th stock and traced the top triple to it so I could cut it, then bolt it to the triple.
I also reinforced the underside of the triple because I wanted to be sure that the bolts did not rip it. The bolts go all the way through. Just make sure you do not use bolts longer than 1 1/2 inch as they will interfere with the ign lock plate in the neck.
You will need to cut two 1 7/8 holes on the ends to allow for the adjusters at the top of the forks. You will weld two inch pipe to the top of the holes. I cut them at three inches, that will give you the factory ride handle height. You can cut to preference if you wish to raise the handle bars. The clip ons will attach to the top of the pipes. Note. I added a bar from one of the clip-ons to the other. That was just to make sure that they could not individually rotate if one or the other loosened. Here are the risers with the clipons attached.
Once you have this done, all you will need is a longer brake line for the front caliper. I used a stainless steel 30' line. It gives just the right length. If you are keeping the original design, the second line that goes over the fender to the left side caliper is 20 inches long.
Here is a pic of the Forks mounted with the lines installed.
I found that the front end swap lowered the bike by 1 3/4 inches. Under very heavy braking, the front fender just touched the fairing under the headlamp. So you will need to trim it.
Once you trim the fairing, you will need to remove the two body mounts under the headlight.
You will have to reposition the horn. If the screws are pointing downwards, you will need to trim. Here is what it should look like.
I used the GSXR speed sensor with the Kat cable and it seems to work just fine. Have not checked the speed against my GPS though.
I could not find a GSXR front fender, so I used one from an SRAD. It mounts on the outside of the actual mounts on the forks, but it works.
Now to the rear wheel. Only one real mod has to be done. The rear swingarm space at the axle is the same for the GSXR as it is for the Kat 1100. Just shy of 10 inches. As Wild-Bill points out in his conversion, the cush drive is the same, so you just swap it. I had all the original spacers for the GSXR.
If you use the left spacer from the Kat, you will have to shim the right side of the rim and mod the caliper strut bar. If you use the GSXR one, you will have to shim the sprocket in order to maintain chain alignment instead. I used stainless steel washers. You only need to compensate for about 1/16 of an inch, so do not shim past the center of the hub that contacts the middle of the sprocket.
I did not need to create any other spacers. But I had to modify the original caliper mount. In order to get the original caliper centered you want to trim the caliper mount. In the GSXR, there is a notch on the Swingarm that accepts the bracket. Becasue I used the original set-up I did not need that part to be there. The section pointing away fron the axle hole has to be trimmed.
You will also have to enlarge and match the bolt holes to the original caliper. I used one stainless washer at each bolt to shim the caliper just a bit. It may not be really necessary. Here is the trimmed mount installed with the original caliper. It is now upside down and with the side normally on the inside, on the outside.
I used my original rear axle and nut. all other parts necessary for mounting the wheel were from the GSXR. Because of the design of the slack adjusters, final mount is a little tight, but no need to expand the swingarm.
This was written as straight forward as I could. It is not all that challenging. It is a pretty straight forward swap.
The benefits are incredible. The bike rides like a new bike. She is very responsive and smooth to attack the turns. I have recommended this to others, and will do so again.
One ting to consider, the front will be lowered almost two inches, and the parkign lot turning radius increases. It will take a little getting used to, but it is not a major thing.
To others that may want to do this, good luck, it is pretty straight forward. Here are finished pics of the bike.
If oyu have any questions concerning info I have left out, let me know and I can answer...
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