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Z900A4 Forks

Posted: Fri May 01, 2020 10:19 am
Author: steve
I'm having a problem with a pair of forks fitted to a A4. When I took them apart, the first thing I noticed was that someone had dropped in a 17mm socket between the spring and the top nut, so my first thought was that the spring fitted must be too short. However, I've measured this at 465mm which is as per the manual but when dropped into the fork tube, it's approx. 50mm from the top. I then turned to the damper, thinking it may be from an earlier Z1 and possibly shorter than the A4 type...the one fitted is approx. 240mm long. In the meantime, the owner of the bike managed to pick up a pair of what he was told were Z900A4 forks and strangely, when he took them apart, they also have the same gap between the spring and the top nut (although no socket this time!).

Could this be just a strange coincidence as it doesn't seem at all right...I'm more familiar with earlier Z1 forks and of all those I've rebuilt you need to compress the spring to screw the top nut in, which gives the spring a certain amount of preload. Of course, we could just fit longer springs but it would be good to understand what the problem actually is.

Any thoughts would be welcome.

Thanks, Steve

Re: Z900A4 Forks

Posted: Fri May 01, 2020 10:35 am
Author: Pigford
Adding a "spacer" to top of the springs is a way to adjust pre-load - a way of altering the static sag.

Not really necessary for a Zed which doesn't exactly handle like a race bike.

Re: Z900A4 Forks

Posted: Fri May 01, 2020 5:53 pm
Author: Jerry
on top of the springs there should be a top spring seat, and then a spacer, 44028-039, probably about the same length of a 17mm socket! are they present?

Re: Z900A4 Forks

Posted: Fri May 01, 2020 6:05 pm
Author: flateddie
my z1000a1 has the 40mm spacer but 1000a2 have longer springs and no spacer have a look at the parts diagram on line

Re: Z900A4 Forks

Posted: Sat May 02, 2020 11:43 am
Author: steve
Thanks all! Having re-checked the parts list, I now realise that I'd missed the spacer and top spring seat...strange how both sets of forks had both these parts missing as well, which only added to the confusion!

Anyway, now sorted...thanks again.

Steve