Z1OwnersClub GB

So, have just rebuilt the front forks(new seals and oil) put back together and the ride is so harsh, even the smallest of pot holes feels as though there is no suspension like hitting it with a flat tyre on the rim. Never rode the bike before I stripped them down so don’t have anything to compare. Correct amount of oil as I measured it out and then measured the distance. Do I need to remove some more oil fit progressive springs? It tracks ok and handles well on snooker table smooth roads but if you hit even the smallest bump it’s horrendous. Ideas please.

What did you set the air gap to?
AL

What does it feel like when you're just sat on it and bounce the forks up and down?
I presume it's not solid?
What grade of oil did you use? If it's too viscous then the compression damping could be a bit harsh if you hit a decent bump in the road.

No air gap and 10w oil. Sat on the bike there is little movement considering they are and old fork. Cheers

Sorry do you mean the psi or the distance from the top of the oil to the top of the fork. No air (psi) and factory setting 110mm.

Did you have the stanchions re chromed? I assume that you checked they slide in the leg with no binding?
I had a similar issue where the stanchion had a tight spot in the leg. Not noticable on flat surface but a sudden jolt locked the fork leg down. Had to dismantle and spend 10mins sliding the stanchion in and out with some fine paste on it until there was enough clearance in the leg. It didnt even mark the chrome and where it was binding was below the seal even if it had.

With the base manual and all the different models in it, the fork oil is filled with the forks fully compressed and the springs removed.
With the supplement manual; the Unitraks are filled with the forks fully compressed and the springs removed.
Within the supplement manual the 1100R1 says; forks fully extendedand the springs removed.
Youre 110mm air gap is correct but i am confused about, under what conditions that should be! Compressed or extended.
Maybe the volume of oil added would highlight which is the correct method.
In any event, i guess you bled the air from the forks after it was put back on its wheels?

AL

Yes filled extended, then pumped then removed the drain screw to release the pressure. I think extended is the correct way as I first filled them with the amount measured out which was spot on the 110mm. There is something wrong as way too hard they don’t budge an inch.

I've never touched a set of 1100r forks, so I might be talking rubbish, but I suspect 'extended' is an error in the manual.

110mm air gap extended is next to nothing compared to all the other conventional forks Ive worked on. Maybe try setting the level compressed and see how it rides?

Olly

Fork oil - 348cc per leg

http://www.kz1000r.com/KZ1000R,%20R2%20 ... tion's.htm

Yes Adrian, that’s what went in after a full rebuild and then fine adjusted to the 110mm. Still no idea what’s wrong, will have a closer look tomorrow. Cheers

harri183 wrote:Yes Adrian, that’s what went in after a full rebuild and then fine adjusted to the 110mm. Still no idea what’s wrong, will have a closer look tomorrow. Cheers

Fingers crossed you get it sorted.

This is the table from the Clymer manual for the model range. It doesn't include the 1100R1 but does list the Unitrak ZX1100 A (KZ1100A) model forks. What is interesting is that it disagrees with the factory manual about the conditions under which the latter is filled with oil. ie. it says; extended here but compressed in the factory manual. Its not unreasonable to assume then that the 1100R1 info in the factory manual may be incorrect.
What is obvious looking at the table is; that those models which should be filled extended have a significantly lower measured oil level for that reason.
This, despite the fact that they all have approx. the same refill quantity, excepting the fact that some are custom models (longer legs) of have extended lower legs (ala Spectre model)
Looks like yours may be hyrdolocked.




AL

Thanks Al, what’s best way to check resolve if they are hydrolocked? Never come across that before?? Cheers

I would dis-regard the manual (s) and fill with oil to 120mm air gap with the forks fully compressed and the springs removed regardless of the volume of oil that entails.

This is what others have been doing, partly because filling when extended is misleading due to the rebound spring or springs having an effect on what exactly; fully extended means.
This is likely to mean removing some oil for you, all of which can be done without removing the forks if you have a good way of holding the bike up with a suitable stand.
It might be worth checking the oil seals under the dust covers before you get going. Even if new they may have blown if the pressure went too high!
Once its back on its wheels you can bleed the air pressure out of the valves on the top caps and see how it rides. Tune them in from there if they need more oil or pumping up on the air assist.

AL