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Z1000J Fork Springs

Posted: Sat Apr 22, 2017 7:16 am
Author: Coose
Morning chaps,

Before I order a new set, does anyone have a set of linear fork springs for a Z1000J kicking about, with a rate somewhere in the region of 0.85kg/mm? It's a bit of a long shot I know, but if you don't ask... :)

Cheers,
Coose

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 10:51 am
Author: mattc
Are a set of std springs from a Z1000J any good to you? If so I have a set from a GPz1100b1 which I think are the same.

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 12:28 pm
Author: Coose
mattc wrote:Are a set of std springs from a Z1000J any good to you? If so I have a set from a GPz1100b1 which I think are the same.


Thanks Matt, but the J springs will be far too light (that's what I have now). But, I'll have a look at the GPz springs and will let you know... :)

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 5:10 pm
Author: Coose
Ah, it looks like the GPz springs will be no better than the J springs. Thanks anyway... :)

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 5:11 pm
Author: Coose
Image

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 5:31 pm
Author: mattc
Sorry I should have checked the bloody manual before suggesting......doh...!

Re: Z1000J Fork Springs

Posted: Mon May 01, 2017 6:39 pm
Author: Coose
It's not a problem, and thanks anyway! :)

Re: Z1000J Fork Springs

Posted: Tue May 02, 2017 10:12 am
Author: tlc
I wonder if your problem is less to do with the springs and more so the damping.
I have fitted Rex forks which are also very soft. Following ZRX forum advice I have upped the preload but also nearly maxed out the compression and rebound damping.
My local racer / mechanic reckons he can make them much better by revalving them.

Or I / you could buy Ohlins :blah

Re: Z1000J Fork Springs

Posted: Tue May 02, 2017 11:00 am
Author: Coose
Ha ha, kerching! :wink:

Being J forks I don't believe for one second that the damping is perfect, but I wouldn't expect it to be considering the basic design. But, the main issue is definitely the spring rate, where once this is right most of the battle will have been won. Half of the overall actual travel is taken up by static sag, which you can adjust with air pressure (which of course does improve matters a little) but then the laden sag becomes excessive as air also doesn't have the required rate. This then leaves very little actual travel before the (what I'm assuming is progressive as the forks don't seem to "bottom") spring rate becomes excessive.

So, the simple step forward is linear springs of the correct rate with no air pressure. I can then consider looking at the damping if I feel it needs it, but the actual wheel control over bumpy roads on on the (rather effective) brakes isn't actually half bad!

Re: Z1000J Fork Springs

Posted: Tue May 02, 2017 4:49 pm
Author: Coose
Hmmmm...... Looking through my collection of manuals it turns out that standard Z1100R springs are linear 1.0kg/mm. They may be a little on the heavy side, but if they'll fit in my J forks they might be worth a try if anyone has a spare set kicking around that they'd be happy to measure for me and maybe part with? :)

Re: Z1000J Fork Springs

Posted: Tue May 02, 2017 7:00 pm
Author: tlc
Grumpy does them for just over £100

Re: Z1000J Fork Springs

Posted: Tue May 02, 2017 7:07 pm
Author: Coose
Aye, Racetechs are about that too and in various rates. I just thought I'd ask if anyone had a set kicking around before I bite the bullet.

Re: Z1000J Fork Springs

Posted: Sat May 06, 2017 7:38 pm
Author: tlc
Coose wrote:Aye, Racetechs are about that too and in various rates. I just thought I'd ask if anyone had a set kicking around before I bite the bullet.


Any good?

https://www.ebay.co.uk/itm/192178663247

Re: Z1000J Fork Springs

Posted: Thu May 11, 2017 7:31 pm
Author: KWACKERZ1
Chris,
Talk to AL he did a lot of work on his J forks and tried various things before fitting emulators. He will be abl to fill you in on the details.

dsfaulkners will make you springs to measure and rate depending on what you want they are probably as cheap as racetech etc.

Re: Z1000J Fork Springs

Posted: Sat May 13, 2017 7:31 am
Author: Coose
Cheers all! Yes, Al and I have been talking at length about forks and other stuff.

Chris - thanks for the link. I'd seen those, and if they hadn't been progressive I'd have snapped them up!