Freebyrd's 81 KZ1000 Build

OK everyone, I finally got some time today and started messing around the swingarm. The front end is mounted, I still need to get the handlebars the way I want it, but its rolling on the front end for now.

I have some questions for people who have done this conversion before or who ever may know. I got a little unlucky. I measured the amount of room in bewtween the pivot mount on the frame, it measured about 9.5 inches. The new zx-9 swingarm measured 10 and 7/16 inches!

So any ideas at all of how or if I can use this swingarm? Also, for mounting the swingarm, I assume I will need to get some kind of sleeve inside the existing sleeve so I can use the KZ pivot bolt?



Also, should I be using the pictured end pieces on the ZX swingarm?





I'm by no means a fabricator, but any ideas are extremely helpful. Hopefully these pictures make more sense. Also, since my swingarm pivot point is too wide, I assume I do not want to cut into the bracing to get it to fit.



Any suggestions or ideas greatly appreciated!

u will have to take a close look at the zx9 arms inner bushings . determine if u can cut some material away ,and or ,move the bushings? U will need quite a bit of alteration for that arm, so i cant say if it is posible without a lot of work.
i made a sleeve to go over the kz axle. u may gain a little width by grinding the inside of the frame bushings . the other option would be to cut the frame rail and spread the frame, but u would need to find a longer bolt then. Larry C went that route so u could pm him for some tips.

Wow, great to see this project back online. That swingarm pivot is really wide. I just went and had a look at a spare swingarm that I have for my zx-10r, and it's 10" wide at the pivot. Now, although the zx-10 is an evolution of the zx-9 it's a wildly different design. On that swingarm there are press in bearing seals at either end. If you decided to eliminate those, then you could probably eliminate about 1/2" from the pivot width.

I'm guessing that the square deal on one end of your swingarm pivot is a threaded width adjuster and on the other side it looks like the thrust side of a tapered bearing.

I'm going to go out on a limb and say that your swingarm is too much trouble. Many easier options exist. GSXR, ZX-6R, GS1000, ZRX are all proven options that are commonly available on ebay. Just sell that zx-9 rear end and buy one off a GSXR 600. The zx-9 was a long lived and very popular bike, you shouldn't have trouble selling the parts on ebay. The little zooks are so common that the parts are cheap and easy to find. And you won't need to widen your frame. I'm using a GSXR 750 swinger and I actually had to space it 0.100" to take up the slack. Just my .02

Thanks for comments guys! You two have been very helpful throughout this and I appreciate it! I'm glad I finally had some time to get back on this too. I started reading the forums and really got motivated by everyones projects. This is an awesome forum.

I have a swingarm from an 80's yamaha sport bike that has been taking up space. Maybe I'll see if it will fit. Otherwise the GSXR one does look like the way to go.

I agree, this swingarm looks like a ton of work to make it work properly. I think I will sell it and try to use a more common one that will fit in the pivot space. Can anyone identify this? This is the Yamaha one I have...

I'm gonna guess it's from a FZR 600

www.google.com/imgres?imgurl=http://www....j2CQ&ved=0CB8Q9QEwAQ

I had to deal with the exact same problem with my swingarm; it was 11 inches wide but there was no good way to trim it down. My best option was to widen my frame to accept the wider swingarm, but that meant more changes to the frame. Since I widened the frame, I couldn't use the stock pivot bolt, I needed to use the doner pivot. The doner pivot was 9mm larger in diameter so I had to make new pivot bushings, cut out the old ones and weld in the new ones. Then I had to....... the list goes on and on. Once you change something that drastic, there is a cascading list of system parameters that usualy must be changed to match. I did all the work because I wanted to use a specific swingarm, but if you don't care what you use, I second the recommendation to use something easier to fit

I was reading your project porchev and your project is very extensive! I'm impressed!

OK so I made some good progress today! Although I dropped a trailer hitch on my toe while pulling the swingarm out of the shed so I'm in quite a bit of pain.

So I pulled the pivot bolt from the fz swingarm and founs it had some bushings only on the outside. It is machined into that shaft though so I can't move them. I then pulled out the bushings from the kz swingarm and found they are the exact same outside diameter and identical length! :woohoo: I was pretty pumped.



So i just put the bushings in the FZ arm, clearanced the inside of the KZ frame pivot point where there is that excess, and in it went! original kz pivot bolt and everything!

Don't mind my camera, it was with my phone and they came out terrible, but its the best I could do tonight inside the garage with the downpours all day. I know we all want pics!









The shock was just in there as a reference. At one point during some of the photos it was wedged against a chain guard bolt that kept it from going any further back.

Is there a formula or method to determine where the shock mount should go? Should I pick a size shock first, or measure and buy the shock accordingly? I'm going to use dual shocks. Should it sit at a particular angle? Should I pick the shock location based on desired ride height? I'm just not sure where I should determine the bottom shock mount if there is a method for it to act properly. Thanks everyone!

turn your flash on.....looking nice.

Awesome, you have a roller. That's a big step. As for the shocks, in a perfect world, you would buy the shocks that you like, and then adjust the lower mount position to achieve that ride height that you need. Then you would purchase the correct springs for your combined weight. However, we often have to make concessions for what we have or what we can afford. I can't give you a majic formula, but I know this much. If you move the lower mount position forward, it raises the bike, and increases the effective spring rate. If you move the lower mount backward, then it lowers the bike and reduces the effective spring rate. Mark1122 can probably offer you some better real world advice. He has the twin shock setup. My bike has mono, so I don't have any useful experience with dual rear shocks.

Here's what i learned.
shocks are designed with a spring weight and damping to be used on a particular bike. this means that they are designed to be placed on that bike at a particular angle , meant to carry a particular weight, and have a particular amount of leverage applied to them.
So, if we can duplicate these needs on another bike, they will work AS DESIGNED. so this is what u need to keep in mind as u go forward on your quest.
1. try your best to mount em on the SAME angle as the bike they came from.
2. try to get them from a bike of the same weight.
3. try to mount them at the same distance from the rear axle as the original.
i used ZRX12 shocks and arm. the kz's weight is similar to a zrx.
i had first mounted the shocks on the stock lower location on the zrx arm and the stock upper location of the KZ. i found that the new more upright position made the shocks VERY stiff. then i moved the upper mount to copy the zrx shock's original lean angle . this made a big dif. and the bikes sag improved and the ride softened nicely.
Now this raised the bike at the back. Lots of guys dont mind a hi ass end. but it looked off to me and decreased the rakes a bit more.
So i raised the front end . i think u have seen this mod in my project post.
Now i am happy with the whole package.
Don't forget to brace the frame , or u will not have improved your bikes handling.

I'm glad you enjoyed torturing yourself by reading my thread. If you REALLY want to make your eyes bleed, read my swingarm thread and my carbon threads :laugh: Even then, I think testarossa has a longer project thread, another good read and he's farther along than me. Hell, YOU'RE farther along than me! I don't even have a roller yet :blink:

porchev914 wrote:

I'm glad you enjoyed torturing yourself by reading my thread. If you REALLY want to make your eyes bleed, read my swingarm thread and my carbon threads :laugh: Even then, I think testarossa has a longer project thread, another good read and he's farther along than me. Hell, YOU'RE farther along than me! I don't even have a roller yet :blink:

Well you did have about a 2 month detour at least with the Carbon Fiber experimenting! :lol: That's pretty cool though and interesting!

I read those threads and Testarossa and marks as well just trying to soak it all in. Lots of great info here.

Do you think it would be possible to achieve a comfortable angle and ride using the stock upper KZ shock mount? I'd love to not have to make a new mount for the upper. Since I already need to completely fabricate two lower shock mount since it WAS a mono shock setup I feel like I have a lot of flexibility. But unlike you, there is no reference to any angle or mounting point on the FZ swingarm. If that makes sense.