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What's wrong with my Z-1?

674 Views 7 Replies 5 Participants Last post by  Robot Chicken
I've got a 2004 130mm marzocchi Z1. It's been a great fork! The oils been changed 3 times since I bought it in the summer of 2004- last changed in august or so. I have another bike and a kid, so this fork doesn't get ridden more than 6x a month.

A few rides ago it started feeling REALLY notchy, especially when side loaded. If I put all my weight on one grip while off the bike, I can get it to basically lock down until I take most all the weight off. It's also starting to feel lots more flexy than it used to.

It is probably due for an oil change, although the seals aren't leaking. However I can't help but wonder if something else is going wrong with it, I've never felt a marzocchi this notchy before. Could it be that it needs new bushings and seals? How much do bushings run for a Z1?
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Do you have an ecc function on that fork, sounds like it's kicking in somehow...
Bikinfoolferlife said:
Do you have an ecc function on that fork, sounds like it's kicking in somehow...
It's got ETA, and the eta leg seems to be the source of notchiness. However it's notchy on both compression and rebound, but only when side-loaded...
It does sound odd, but do an oil change with some good quality stuff soon. I sometimes change the oil once, ride the fork for an hour, and change it again. That way the fork gets really well rinsed inside with fresh oil before the final change. In my experience, it is the rebound leg which gets all gucked up. The ETA leg usually looks pretty fresh still.
Good advice Tscheezy, will do.

In past oil changes, the oil has looked pretty good compared to other marzocchi forks I've owned, so I am thinking the bushings should be fine.

Oil change is basically free and a good opportunity to investigate further...

tscheezy said:
It does sound odd, but do an oil change with some good quality stuff soon. I sometimes change the oil once, ride the fork for an hour, and change it again. That way the fork gets really well rinsed inside with fresh oil before the final change. In my experience, it is the rebound leg which gets all gucked up. The ETA leg usually looks pretty fresh still.
I would guess that your bushings are wearing. You say it is flexier and it doesn't compress when side loaded. Do you have play in the fork when you hold the wheel between your legs and rock the bike sideways? Of with the brake on and rocking it back and forth?

_MK
The play I noticed was mainly standing besides the bike, pushing down on one grip only. It almost feels like one leg is OK and the other is notchy/loose.

Another thing that occurred to me: I have never ran air pre-load in this fork and it's always felt fine. recently I added 5-7psi to the non-ETA leg for a north-shore descent- and that was the same day I noticed the problem. Perhaps in imbalance in the spring stiffness (due to air pre-load) is behind this- it makes sense based on how the fork feels.

I'm going to change the oil and lose the air pre-load, hopefully that will set things straight.

MK_ said:
I would guess that your bushings are wearing. You say it is flexier and it doesn't compress when side loaded. Do you have play in the fork when you hold the wheel between your legs and rock the bike sideways? Of with the brake on and rocking it back and forth?

_MK
FM said:
The play I noticed was mainly standing besides the bike, pushing down on one grip only. It almost feels like one leg is OK and the other is notchy/loose.

Another thing that occurred to me: I have never ran air pre-load in this fork and it's always felt fine. recently I added 5-7psi to the non-ETA leg for a north-shore descent- and that was the same day I noticed the problem. Perhaps in imbalance in the spring stiffness (due to air pre-load) is behind this- it makes sense based on how the fork feels.

I'm going to change the oil and lose the air pre-load, hopefully that will set things straight.
I've messed around with tons of these forks. Air preloading one side is not going to cause notchiness in itself, esp. at only 5-7psi. There might be something else being effected by the air preload, though.

I'm pretty sure you have either a bent push rod or bad bushing. Remove the internals when you open the fork up and see if the spring and damping push rods are moving smoothly. Takes a while, but is better than having to open it twice.
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