KX Suspension upgrade will begin on Tue!!

[Trentec]

I got an older KX it is not a 100 but rather a big wheel 80 I am not sure of the year can someone let me know which digit gives up that info I would be happy to share in case this is an easier swap. It has the upside down forks and an incredible plush feel to it compared to the DRZ. The suspension has been rebuilt and from initial checking it appears that the swing arm pivot bolt is the same diameter (hope so) the DRZ seems to have a wider in the rear but almost identical swing arm it may have been modified from the earlier KX design.

[beamishnz]

good luck, look forward to hearing how it goes. Call your local Kwaka dealer they will give you the year from the frame number. Also the Kawasaki.com web site is a great surce of parts drawings and info including a facility to cross reference which models and bikes share parts. There may well b a way of identifyong the year from this site too.

[Trentec]

Well I couldnt wait so I did the front end after work and as god as my witness it took longer to scrape the old stickers off than it did to install these forks! The bike still feels worse than the KX did so there is more to blame on that rear shock than I thought. The kid down the street doesn't like me anymore...lol Maybe I will look for an old roller for him and make his dad a deal on the remaining parts. I cant bring myself to put the drz suspension on the kx I just dont think it would be safe.

[Trentec]

I have the swing arm ready to go in but the upper shock mount has to be trimmed (for the shock I have) to clear, it only needs a little grinding though. I went a different route with the pivot bolt than Dr_Drz did I decided to make the other holes smaller using bronze bushings (no they didnt start out the correct size) it works great so far meaning that it will work but long term will have to be seen about. The bolt issue was solved with the rear axle bolt from the DRZ (same as the KX diameter but longer) so we cut 7\16 20 (no metric dies) down to where the other bolt was and cut the end off and I had a long KX bolt! I read in Dr's thread that someone had said the linkage mount on the DRZ was weak and they were right Im not sure if it is too weak for what I will be doing but the KX has a much stronger system and mounts via a bracket in two places I may reinforce the stock mount and I will see what room there is to use the KX bracket and make a mount if I can. If I had this to do over I would say the whole thing could be done in a day providing you have everything on hand and the steel for the new brackets. But I would budget two days on the first one and longer if any of these procedures are new to you. The only thing left to consider for me is the linkage for the rear suspension the drz has a shorter (eye to eye) pivot and will change the leverage ratio (correctly suggested by Zomby in one of his threads) and make what was a very balanced suspension stiffer in the rear so I need to find a way to use the kx part or I will need stiffer springs up front or weaker in the rear to try to balance it again. I will try to get some pics of the bushings installed and any mods I may do to the linkage mount. Hopefully I will get it done on sat. For the brake cylinder bracket I will try to do as was suggested by Dr_Drz and make the leverage ratio the same as the KX.

[Trentec]

Got side tracked by a nasty combination of life and a DR250 that belongs to a freind of mine.

Has anyone used the kx linkage? Any way to regain the lost travel from the upper shock and linkage pivot being lower in the frame in relationship to the swingarm pivot? I am going to try a longer link or "dogbone" to get the shock off the swingarm, would lowering the swingarm mount help? Maybe giving the same or closer degree of travel of the kx linkage? I may just go back to the drz setup it worked but it was too hard after three inches or so of compression.

[Trentec]

Ok I slept on it and came up with this:

I can regain the stock kx linkage movement with longer links but it will lower the rear about 3\4" or I can do major surgery and raise the mounts up to be the same as the kx (part of that would give me a full frame also). Does this sound right? What shock would be longer by an inch or so?

[Trentec]

Ok I think I have it figured out the kx dog bones are longer but not long enough starting the pivot out at approx 30% of its intended rotation. Then you hit the hard spot when the bolt holes in the swing arm (lower) the center pivot and the frame mount are parallel like pulling a rope tight. So if I'm right that explains why people are going to extra light springs because except for the first couple inches of travel you basically have a swing arm mounted shock? If I make longer dog bones I could fix the rotation problem in relation to the swing arm but it will lose the wheel travel proportional to the increase in the length of the dog bone. So the only way to get it to work the way it was engineered is to move the linkage up on the frame about three inches for the kx linkage. The drz linkage is shorter eye to eye so it's quicker through the rotation.

Since there seems to be no interest in this, I wont post anything more on this subject until it is finished, it will be a little while before the frame cradle and mounts will be ready anyways. But the end result will be a much stronger frame and the stock KX suspension geometry front and rear as well as gaining the kx travel in the rear.

[Smartt Yamaha127]

Keep working on it. Sounds like you are doing good.

[Trentec]

Stock kx frame mounting bracket to get the exact location of the mount. No tough stuff here the bracket locates the frame mount, the swingarm hasnt changed and the upper shock mount has plenty of room to go up and will locate itself (all but the angle) plus it will then clear the exhaust and may let me use the stock chain roller location all a relief because I was worried about the air box outlet tube with the shock raised on the left side.

I will get on the fabrication early next week I hope.

[Rev Hard]

GREAT JOB! The forks look good. I cant wait to see the rear end conversion!...what year are you using for the rear?

[Trentec]

Thanks, I was told it was a 94 but Im still not sure (all I could see was the suspension...lol) the price was right and I have the rest of the KX to part out so I should have between 200 and 300 dollars in the parts I keep depending on what I get for the rest of it. I did get to ride the KX before I tore it apart and the suspension was night and day compared to the DRZ, old as it is.

[Rev Hard]

Sweet, keep us posted

[Trentec]

Initial welding and fit-up is complete and the bike feels like the kx did. I have to tidy up some details and repaint and I will post some pics. The seat height has increased to 33.5 and with a new tire and the forks raised back up it will be close to 34 maybe a little taller but it sags about 2 inches with the current spring \ preload combination and will of course have to be tinkered with. But the over all rear suspension is a success before testing at least.

[Rev Hard]

POST THE PICS!!! haha

[Trentec]

I have a honey-do list as long as my arm. Then I get to do the yard work and then I can get to the bike if I have time! To make matters more interesting I am considering ripping it back to the frame and building the cradle so I will have less work to do when the 200 is ready. Besides it just sounds like fun!

[Trentec]

Ok it's assembled and running again I have to put the new chain on saved it till last trying to locate a 428 sprocket for the KX rear wheel but nuthin yet so it stays for a while. The kick stand is now about three inches too short and almost useless I can push it over with one finger. Looks pretty much the same but it has a much better feel to it. I made a heat shield for the nitrogen res and brake lines and it worked out pretty good fit wise. I should have the pic tonight after work.

[Trentec]

[Rev Hard]

THAT IS SICK!!!!!!!

Its a lil hard to understand so i might ask some questions that u might have posted.

So you put bushing to make the swingarm hole smaller? Right? , then you grinded down the upper mount for the shock and cut the DRZ bolt a lil shorter? Am i still on track? And u also used the KX linkage? Sorry for all the questions but it was a lil hard for me to understand

[Trentec]

THAT IS SICK!!!!!!!

Its a lil hard to understand so i might ask some questions that u might have posted.

So you put bushing to make the swing arm hole smaller? Right?

No, to make the frame and engine boss smaller the drz had a larger diameter bolt. But boring the swing arm is a better plan as Dr_drz did.

, then you grinded down the upper mount for the shock

Cut it off flush with the bottom of the horizontal frame bars (seat bars) with a sawsall and welded in a 3\16 plate and a new mount.

and cut the DRZ bolt a lil shorter?

I used the axle bolt from the drz because it's the same diameter as the KX swing arm bolt and cut new threads down to where they needed to be and cut off the rest.

Am i still on track? And u also used the KX linkage?

Yes all of the KX linkage was used. The only DRZ part in the rear suspension is the frame it's bolted to. The linkage mount is where the most work was it had to be raised, widened and clearanced for the KX linkage and the KX frame brackets had to be profiled and welded to the DRZ crossmember.

Sorry for all the questions but it was a lil hard for me to understand

No problem I am almost entirely self taught so questions are a way of life for me

I am not as mathematically inclined as some of the other people here and I don't pretend to fully understand the geometry that goes into engineering a rear suspension so I just used the skills I have and re-created the KX mounting on the drz. I'm sure the DRZ parts can be made to work very well but it was beyond my ability's to get it right, so I just took what was right to begin with and moved it to the DRZ.

[Rev Hard]

Thanks for clearing it up for me!!! BTW, how much did this GREAT project cost you? A 1996 is something i could possibly find, and I'm always up for projects!!

Oh, could you also get a picture of the foot brake and how you did it? I remember that dr_drz had to cut and weld his one.

Thanks