Marzocchi z1 bomber coil help/advice?

[SoyWater]

Ok. Lets get this out of the way up top, I’m stupid. That being said, I’ve got a fork problem and since I’m the dummy in the group, I hope someone smarter than me has been here…

I’ve got a marzocchi z1 bomber coil, 2020 model, I believe. It needed seals and a lower service and I was underwater with other stuff and didn’t have the bandwidth to fuck with it. So, like a dumb shit, I took it to the lbs for a lowers service, because I like to support a local business. Picked it up, paid my money, seemed fine other than the gouge in the crown from unscrewing the spring cap. Whatever, park bike, its gonna get scratched.

First trip to the park and its only getting 130mm of travel (170mm fork) and leaving 40mm on the table. Ok, different frame, slightly steeper, shorter, higher bb, maybe it needs a softer spring. Swapped to a medium spring (150-180lbs, I’m 185) and samey-same. Maybe only leaving 30mm now?

So, at this point, I’m convinced the fork got put back together incorrectly at the lbs. I paid them a visit today and was able to convince them that dealing with me through a whole-ass warranty process was gonna be so much more expensive and unpleasant than just refunding what I originally paid for labor, letting me be on my way and never having to look at my face again. I’ve lost that loving feeling regarding that shop and don’t trust them to fix my shit. They agreed.

Now, If I’m gonna let an idiot work on my crap, I’m gonna be him. So i need to figure out just exactly wtf is going on with this fork. I am going to reach out to the vendor i purchased it from and see if they’ve ever seen this, as well as reaching out to fox and seeing if i can get some kind of service diagram or if they have any other suggestions.

Question to you all, have you ever experienced this? If you were me, what would you be looking for? Any help would be greatly appreciated.

Pictures if they help.

When i first noticed, park weekend, compression dial fully open, firm spring.

Medium spring, compression dial open. Right after a run down a back jump line casing the absolute shit out of a few very big tables.

Anyhoo, if anybody has any ideas, I’m a friggin cornfield.

Thanks.

[truth]

@SoyWater

oing to reach out to the vendor i purchased it from and see if they’ve ever seen this, as well as reaching out to fox and seeing if i can get some kind of service diagram or if they have any other suggestions.

Question to you all, have you ever experienced this? If you were me, what would you be looking for? Any help would be greatly appreciated.

I think this might be your configuration manual. It looks like changing the order of the spacers could get from 170 down to 150. Maybe they threw extra spacers in too?

Bomber_Z1_Coil_tuning_guide_RevA_Z1Coil_ConfigurationGuide_1.pdf (1.6 MB)

[SoyWater]

Thanks for that!

I considered the spacers might be in the wrong order, or place but shuffling them around physically changes how much fork leg pokes out of the lower, it doesn’t just take travel away off the top. I hadn’t considered extra spacers, but at this point

Damn it. All I wanted was the seals changed.

[Luniz82]

As far as I know, the zocchis have a semi open bath damper cartridge. That means that you can “adjust” the progression ramp up towards the end of the travel with the oil level in the fork legs, just like adding tokens to an air spring. Maybe check how much oil is in there, it might be too much.

[SoyWater]

This makes sense. Everything else seems to work fine, compression and rebound do their thing, it sags a little under the weight of the bike and does the bounce test just fine, it just will not use all the travel. Too much oil could be a real simple mistake. I’ll check that, thank you.

[SoyWater]

Welp, shit. I finally got around to pulling this fork apart and there is absolutely nothing visibly wrong with it. Even the oil level was correct, down to the cc. If I take the spring out, I can manually compress it to within 10mm of full travel and I think that last 10 is a bottom out spring, so…everything seems to work. Travel spacers are in the right place and of the right number. I am confused.

So, when all else fails, get creative, right? I have a thought. Theoretically, the only thing that should have been changed were the seals, wipers and oil. When I manually compress the fork with no spring, I can feel a decent amount of air pressure resistance just from the air trapped in the lowers. I think I actually had to bleed a little to get it to compress completely.

I don’t think that would be enough under regular circumstances to do what I’m seeing, so this is where I get into theory. Albuquerque is 5500ft, the base of the lift at the bike perk is 8420ft and the top is 10,600. Less air in the air. If I bring chips they’re always near bursting from the pressure difference, I’ve had contact solution pop open from the same…so i wonder if my nice, new seals are trapping a volume of air in the fork legs that’s expanding with the altitude and screwing with my fork. The newer fox stuff has bleeders on the lowers for that exact reason, I think.

Possibility? Stupid ramblings? Ovaltine? Anyway, I think what I’ll do is slip a zip tie past both seals the next time I’m up there and see what happens. Guess I gotta go to the bike park next week. Darn.

[Mystik]

It is definitely due to the bottom out feature built in. It has been a while since I have read about it so I can’t remember the details, but there are some threads out there on other forums of people with the same problem. I know somewhere out there, there is one of a guy who came up with a way to “fix” it. He drilled out something in the fork so that it doesn’t get so progressive at the end of the travel.

I have one of these setup as 150mm, I have never used more than 140mm. I’m not riding anything too rough, so I’ve never worried about it. I know that they said when configured with longer travel it is even more of a problem.

[SoyWater]

It was never a problem until i took it for service. Last season it would use every bit of 170mm. Every. Bit. Then I had the seals changed and now it does this. Sorry, but it’s not “just how it is” and i know it. If it never used full travel that would be something but…its just not. I’m not sure I can be clearer here, it worked beautifully, I took it for service and now it has changed how it works.

Also, the idea that the “bottom out protection” is really just 40mm of unusable travel doesn’t seem quite right. But, like I mentioned, I’m fucking stupid, so…who knows.

Further edit, I did a little digging yesterday and found a chart where someone measured the rate of their spring and then the entire, assembled fork. If I’m reading it correctly, the trapped air alone was worth around 50lbs of spring rate at the bottom of the stroke. Pretty sure the medium spring in this fork is a 45 lb/in spring, that would be a significant increase, and mostly toward the bottom of the stroke, where I’m having problems.

Still can’t attach a link for some reason…

[Mystik]

The trapped air problem is what I’m referring to, marzocchi markets it as a form of bottom out protection. That might just be a way to market a problem as a feature though. Maybe before you had it serviced you had a slight leak which allowed the trapped air to escape, or maybe you have another problem all together. I just know you aren’t the only person to have this problem with this fork.

[SoyWater]

Okey dokey.

[SoyWater]

I was trying to quote your bit about the leak but the forum is just fighting me recently, being very uncooperative, but i did have that same thought yesterday. Matter of fact, the only reason I got it serviced in the first place was it was weeping a little oil out of the seals. This fork was on my hard tail for a few years then sat, unused for a couple more until i strapped it to last seasons park frame

There’s also this,

If I remove the spring cap, and just shove on the thing I can get, basically, full travel. But it takes some doing to hold it there, its actively hard to hold the fork fully compressed with one hand and take a picture with the other, but here ya go

Get my weight off it and it springs up to here

Guys. I’m not real smart, but i think that could be an issue. I pushed a zip tie past both seals and it “pssssh” a little air out, I set the fork about 1/3 through the travel and pulled the zip ties. Now, with no spring, it has the tiniest vacuum at full extension but the spring easily overcomes that and it should be neutral-ish at sag. I’ll rinse and repeat that in the bike park parking lot and see how it goes.

[SoyWater]

And bingo was his name-o. Burped the lowers at altitude and we’re back in business. Just in case anyone else has a similar problem. I’m considering adding a bleeder to each lower just for fun. Anyway, thanks for the help everybody. I appreciate it.