KZ1000 Suspension. What have you done to your KZ?

I am borderline with fixing the stock suspension, and upgrading to a modern super sport bike suspension... I am trying to do my homework on what can be done to fix the Pogo Stick stock suspension...

For the front end, I figure that stiffer springs, and better valving is going to be the ticket... Better option than just installing preload spacers to original springs and going with heavier weight oil... This seems like a patch job, rather than a fix to the problem.

Seems like most people are in favor of progressive springs... I imagine that this is for a more comfortable ride...

I have not been able to find information on what springs come in the stock suspension... However, I found the following relevant information from www.progressivesuspension.com


FRONT SUSPENSION SPECIFICATIONS

Spring Free Length 20.75" Inches
Spring Outer Diameter 0.99" Inches
Progressive Spring Rate Pounds / Inches 35/50

Spring Free Length 527 Millimeters
Spring Outer Diameter 25 Millimeters
Progressive Spring Rate Kilogram / Millimeters 0.63/0.89


REAR SUSPENSION SPECIFICATIONS

Shock Free Length Inches 13.50"
Shock Compressed Length Inches 10.70"
Shock Travel Inches 2.80"

Spring Free Length Inches 9.37"
Spring Inner Diameter Inches 1.85"
Progressive Spring Rate Pounds / Inches 90/130


Shock Free Length 343 Millimeters
Shock Compressed Length 272 Millimeters
Shock Travel 71 Millimeters

Spring Free Length 238 Millimeters
Spring Inner Diameter 47 Millimeters
Progressive Spring Rate Kilogram / Millimeters 1.61/2.32


IF YOU GUYS HAVE DONE SUSPENSION WORK / UPGRADES, PLEASE SHARE WHAT WORKS...

I will update with more when I find new data...

Luis

According to www.RaceTech.com calculator for a 200 lbs rider

Forks Springs should be 1.0 kg/mm (56 lbs/inch)
Shock Springs should be 3.1 kg/mm (173.6 lbs/inch)

Luis

Luis
I have fitted the entire suspension and brakes from a 1995 GSXR 750 to my 78 KZ1000 A2. In the process, I rebuilt the GSXR fork with springs that are the proper weight for the rider/bike combo. I also rebuilt the mono-shock with the proper spring and fitted a Gold Valve
Kit from Race Tech. Obviously the brakes got fresh pads, fluid, and seals as needed. I also installed braided stainless lines at the time.

I purchased a complete donor GSXR off Craigslist so as to have the original bike there for measuring purposes. I set up the new suspension with the geometry as close to the donor bike as possible. My KZ frame was checked for squareness and braced in the process of fabricating the attachments for the newer suspension. All that is to say that I tried to "do it right" to the best of my abilities. I got lots of help from members here along the way. It took about a year of nights and weekends to complete my project. I urge you to read my thread and OldManRock, Mark1122, anything by blackbanshee531. I made my thread in painful detail so that folks considering this option do so realizing the commitment necessary to follow through with this.

It's worth it if you follow through. My bike handles very well and stops a million times better with the new brakes. The only thing I lack is something I suspect you already realize. The bike could use a little ride height. I can drag my header collector on a tight right hander. I have a plan to solve that in the future. As it is I can achieve 1/2" chicken strips on the street given my cornering clearance limitations. That's actually fine for what I intend my bikes purpose to be. If I want to go faster I can hop on my ZX-10R.

There is a link to my build thread in my signature line. I hope you have some spare time. It's a long one. Don't start it if you can't finish it. There are lots of really cool unfinished projects on this forum.

The original rear shocks really were better suited for pogo sticks. :laugh: If you're considering staying close to stock consider Hagon shocks for the rear. Contact Dave Quinn (see link) and he will set up a pair for your specific bike, riding style, weight, etc. I put a set on my bike 6 years ago and they are still great! Along with providing superior suspension they have stainless steel bodies and shrouds.


For the front, as a start, you may want to simply change the fork oil and put in Bel-Ray 15w. Put in the correct amount (measure down from top of fork tube). This will cost nearly nothing and may give you the handling you desire. Some bike's haven't had the fork oil changed since Gerald Ford was President! I've used Bel-Ray since day one and change it every 2 years. It has given me great results. Ed

davequinnmotorcycles.com/cgi-bin/webc.cg...GON_TWIN_SHOCKS.html

race tech emulators,a fork brace and a stiffer swingarm would go along way to taming the handling of these old beast.

vintage or modern you can improve the handling quite a bit with the right mods.
it depends on the "look" you want.

i built my own swingarm and stuck some wide rubber under the back of mine and transformed the handling.





thats my .02,

leon

531blackbanshee wrote: race tech emulators,a fork brace and a stiffer swingarm would go along way to taming the handling of these old beast.

vintage or modern you can improve the handling quite a bit with the right mods.
it depends on the "look" you want.

i built my own swingarm and stuck some wide rubber under the back of mine and transformed the handling.

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Leon. that is a beautiful bike, great job.


thats my .02,

leon

Well, I figure I see what it takes to mount ZRX1200 Shocks on the KZ1000 They are 9/16 longer than stock shocks I spaced the left shock 3 mm, and removed 3 mm off the top of the chain guard tab...

Settings:

Lowest Pre-load.
2 Rebound.
2 Compression.





The ride height is welcome... The suspension travel increased... And, the quality of ride is 10 times better... I went on a bumpy road... I could only feel the front end...

Now that I have the spring specifications I will look into 1.0 kg/mm straight rate springs and either 20W Fork Fluid or Racetech Gold Valve Emulators...

Luis

That's some serious clearance you got there! :blink:

Luis,
Race Tech sells Gold Valves and proper rate springs for the ZRX shocks. I am using a set of YZF600r cartradge forks on my 1980 KZ1000 ltd. They are 1.25 inches longer then the stock KZ forks so I won't have to worry about ground clearance.

2004 gsx-r front and rear swap

wireman wrote: That's some serious clearance you got there! :blink:

I know... The swing arm finally has some angle to it, instead of being so flat... Right now the shocks have little pre-load so it sags back down when you seat on it... However, the bike does not squat so noticeably under hard acceleration... In fact the front tire saw some air the other day...

Long and flat swing arms seem... Unnatural. (I mean contrary to geometry settings for performance handling)

Derigo wrote:

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2004 gsx-r front and rear swap

This looks really good... Matching wheels go a long way to make the bike look balanced...

82 GPZ750, with a 1135cc engine. Rear swingarm and shocks from a 2000 ZRX1100, front end is a stock 81 GPZ1100 with a fork brace and progressive suspension fork springs. Thing handles really well.