KZ750E rear shock spring stiffness

Hi all,

During the last project work I replaced the rear shocks with some pattern parts (said to be for KZ650 and KZ750) from a supplier in England. Having got the bike going, the new ones seem really, really stiff. I wish I'd kept the old ones to compare. I've only done a couple of hundred miles on them so far, but on our rough roads with speed humps as well, they are not comfortable. The butt-o-meter says they are noticeably stiffer than my old Honda CBR600F.

With the preload set to minimum, putting all my 75kg weight over the back of the seat, they deflect by about 14mm. Does anyone know a normal stiffness for these? Or would someone with new-ish OEM springs measure how stiff they are?

There is no damping adjustment on the shocks either. The damping seems to match the spring rate OK. I'm fearing another case of buying cheap, then buying again expensive! Or is it cheaper to eat burgers until my weight matches the springing?

Thanks all,

Rupert

Here is a good article about measuring sag... racetech.com/articles/SuspensionAndSprings.htm

The stock suspension travel is only 95mm. I think you want about 25% or so used up by sag when you are sitting on the bike in your riding gear.

Thanks! Those shocks are about twice that stiff. I saw on other posts prog springs at 100-140lbs per inch, and mine are about twice that, too.

R

No offense intended - but are you positive the shock springs are set to the softest rather than the stiffest position? Ed

Is it possible to just replace the springs? Some companies supply springs rated to your weight,riding style etc. Or take your old ones apart,swap the springs and see how that goes.

None taken! 100% sure (after going out to check one last time! )