Mountain Bike Reviews Forum banner
1 - 9 of 9 Posts

·
Slowest Rider
Joined
·
5,237 Posts
Discussion Starter · #1 ·
I am very happy with my Marz AM1 fork and it's been working great for my XC rides, even at my 250#. The ETA is super for climbing geometry and suspension. The TST can be adjusted on the fly as I hit different types of terrain. All of it is solid and super plush in just the right way. Even handles my 8" Saint disc brakes.

But I got issues after I recently had the fork serviced by my LBS after 6 months of riding - they changed the oil in the two sides and the TST. After servcing, I find it much harder to get the fork to stay down after engaging the ETA lever. Before, I'd flip the lever and push down and the fork would drop several inches and stay. Now it won't stick down easily and comes right back up. I have to keep pushing down again and again. After several attempts, it slowly goes down a little more each time before getting close to the 1-2" travel point I remember easily getting in just one good push before servicing.

The techs at my LBS are in thick with Marzocchi's techs. They said they only put 130 cc of oil in the left ETA fork, even though the web site says 180 cc for the left ETA side of the AM1, because the Marz techs said that 130 cc was better. The LBS said the ETA will hold down easier on real ridng (rather than in-shop tests) where the oil is being pushed around by frequent fork travel. When the fork's been at rest, the oil drains and it's harder for the ETA to engage. But I find on real trails, it's still hard to push down the fork after engaging ETA ever since their servicing.

Does anyone know the right oil level for the ETA side of the fork? Could this be my problem? Thanks
 

·
mtbr platinum member
Joined
·
1,426 Posts
BigLarry said:
The techs at my LBS are in thick with Marzocchi's techs. They said they only put 130 cc of oil in the left ETA fork, even though the web site says 180 cc for the left ETA side of the AM1, because the Marz techs said that 130 cc was better. The LBS said the ETA will hold down easier on real ridng (rather than in-shop tests) where the oil is being pushed around by frequent fork travel. When the fork's been at rest, the oil drains and it's harder for the ETA to engage. But I find on real trails, it's still hard to push down the fork after engaging ETA ever since their servicing.

Does anyone know the right oil level for the ETA side of the fork? Could this be my problem? Thanks
This is your problem. You need 175-180cc's!
 

·
Slowest Rider
Joined
·
5,237 Posts
Discussion Starter · #3 ·
bikerx40 said:
This is your problem. You need 175-180cc's!
Thanks! :D

I read through your web site on Marz fork repair (in your signature of your post). Of particular value is the paragraph in FAQ titled "My ETA (extension travel adjuster) stopped working. How can I fix it / What's wrong?" in which you say adjust the oil height correctly and get air out of the ETA cartridge by cycling it during oil fill. This section makes it obvious the lack of sufficient oil is my problem.

I'm getting a new shop for this repair. I might be tempted to do this myself with your nice detailed instructions. (It's impossible to find an Marz shop manual anywhere, which doesn't help the shops much either.) But I have the TST instead of the HSCV on my AM1 versus your Marathon S instructions and many steps may not be the same. I've heard the TST oil change is tricky as well.
 

·
Registered
Joined
·
868 Posts
There isn't really much to doing Marzocchi fork work in your own garage. You need some golden spectro 7.5 wt oil and the right tools.

One other thing to try. Engage the ETA and then just back it off a little bit so the fork rebounds very very slowly. You should hear a sucking sound and then at the end of the rebound, when the fork is almost at the top of its travel it will have a fast pop to the top of the travel with a different sucking sound. I suspect that is the ETA cart not being completely full. Pump it in this "ETA almost on" position and the pop at the end of the rebound stroke will get shorter and almost vanish (assuming you have enough oil in the fork). I have found that if you charge up the cart like this it stays down a lot better when your ETA is on. Maybe this will help, but you probably sould get the right amount of oil in there anyway.
 

·
Slowest Rider
Joined
·
5,237 Posts
Discussion Starter · #5 ·
robsetsfire said:
There isn't really much to doing Marzocchi fork work in your own garage. You need some golden spectro 7.5 wt oil and the right tools.

One other thing to try. Engage the ETA and then just back it off a little bit so the fork rebounds very very slowly. You should hear a sucking sound and then at the end of the rebound, when the fork is almost at the top of its travel it will have a fast pop to the top of the travel with a different sucking sound. I suspect that is the ETA cart not being completely full. Pump it in this "ETA almost on" position and the pop at the end of the rebound stroke will get shorter and almost vanish (assuming you have enough oil in the fork). I have found that if you charge up the cart like this it stays down a lot better when your ETA is on. Maybe this will help, but you probably sould get the right amount of oil in there anyway.
Thanks for your suggestion. I think my oil is so low even your nice trick isn't working. I find the fork doesn't hold down at all (at first) and immediately shoots back up. Only on repeated pushes does it begin to hold even a little. Backing off the ETA lever even a little causes the very weakly held fork to immediately shoot up. It's well beyond simple fixes I think.

I may just pop open the top and add more oil if I can figure out what weight the shop used. (They may have used 10 wt. for my 250 lb size - I'll call and ask.) For a check, does the 175 or 180 cc fill equal the 45 mm from top formula? (I need 180 cc for my size.) Maybe I can find out exactly what fill the shop did and just add the difference.

But my $800 fork still under warranty and the shop clearly messed up. I can probably get them to do this oil level fix for free (if I still trust that shop).
 

·
Registered
Joined
·
868 Posts
BigLarry said:
I may just pop open the top and add more oil if I can figure out what weight the shop used. (They may have used 10 wt. for my 250 lb size - I'll call and ask.) For a check, does the 175 or 180 cc fill equal the 45 mm from top formula? (I need 180 cc for my size.) Maybe I can find out exactly what fill the shop did and just add the difference.
Marzocchi has gotten away from using the mm from the top of the fork. I suspect this is because it is hard to measure and you have to take the spring out in order to do it. I would recommend adding a bit of oil at a time until the ETA works, but you can dump it all and start over. Make sure that you get nearly all the oil out if you dump it because some will be in the cart so you will have to pump it a few times.

I don't know is 180cc will equal the 45mm from the top (without the spring). I do know that a 1 fl oz shot glass is approximately 30cc and a 1.5 fl oz is 45cc, so that gives you an idea of what you need. I would start small and try to get the ETA cart to fill up.

Get the correct socket (possibly a thin-wall will be needed, although I don't think you need one, I think it's a 21mm) to open up your fork. Do not use a cresent wrench or something else. A $5 socket is worth having to get a new top cap to replace the one you galled up with the wrong tool.

It is somewhat harder to get the topcap and also the spring off the damper, so I would just unscrew the topcap, take the air out of the other leg and compress the fork. Pour a bit of oil down the spring, put it back together and see if you can get the ETA to charge up. If you can't repeat, but go slowly with the oil (although you can always pour it out and start over if you mess it up). If you have too much in it, you will not get full travel out of it.
 

·
Slowest Rider
Joined
·
5,237 Posts
Discussion Starter · #7 ·
ETA Holds now

Thanks for all the advice, everyone. It helped convince my LBS to try adding more oil to fix this issue.

Adding a little oil indeed fixed the problem with the ETA. :) But the extra 10 cc of oil to 140 cc reduced my travel by ~10 mm??!!

I had sent an email to Marz about this problem, and if I should put in 130 cc, like my LBS techs swore was correct, or the 175/180 cc on their web site. I got back the following terse response from Marzocchi in full, exactly as they sent it:

"Try the 50ccs more of oil. It might be sucking air into the cartridge, also what type of oil did the tech use in the fork and what did he use to measure the oil into the fork."

The LBS techs used the correct 7.5 weight oil (can't remember exactly what high quality brand), and an accurate syringe with cc scale to inject the oil. No problem there. Marz service is fishing without a clue as to the correct oil level in their own fork!!!! :(

To check Marzocchi's higher 180 cc oil level claim, my LBS humored me and put the recommended 175 cc into the fork and let me come in to try. The fork set at 140 mm travel could only go down half way at best!! (But the ETA problem was fixed.:rolleyes: )

So the LBS was indeed correct after all! But in order to fix my ETA, we decided to try putting slightly more oil, 140 versus 130 cc. It definitely fixed the ETA issue, but I can only get about 125 mm of travel before steep resistance with 140 mm travel set on the TAS. Previously at the lower 130 cc of oil verbally recommended by Marz and my LBS, the fork would push down almost the full 140 cc with all my weight on the front and the weaker DH TST setting. So I may have lost a little travel - maybe 5-10 mm. I might try to go back to 130 or 135 cc of oil, but wondering if it's worth the effort for the slight travel loss.
 

·
mtbr platinum member
Joined
·
1,426 Posts
BigLarry said:
Adding a little oil indeed fixed the problem with the ETA. :) But the extra 10 cc of oil to 140 cc reduced my travel by ~10 mm??!!

Previously at the lower 130 cc of oil verbally recommended by Marz and my LBS, the fork would push down almost the full 140 cc with all my weight on the front and the weaker DH TST setting. So I may have lost a little travel - maybe 5-10 mm. I might try to go back to 130 or 135 cc of oil, but wondering if it's worth the effort for the slight travel loss.
If you can obtain full travel by pushing all of your body weight down on the fork in the DH TST setting then you should definitely add more oil. Unlike a fork like the RS Pike, Zokies are designed to ramp up significantly during the last 20% of the travel. The ramp up is required because Zokies don't use any bottom-out bumpers, and a harsh metal-on-metal bottom-out isn't great for the fork.

IMHO, your fork's oil height should be set so that you use about 90-95% of your available travel on an average ride. This would mean 125-133mm. The last few mm's of travel should be saved for those unexpected casing of jumps or poor technique drops to flat. Pushing for fork down with all of your weight should give you about 85-90% of your travel.

Anyway, make sure you are getting proper sag, and then dial in your oil height and I think you'll enjoy your fork more in the long run.
In addition, the last 10-15mm's of the fork travel will ramp up heavily due to the stiffer spring rate of the ETA spring being compressed.
 

·
Slowest Rider
Joined
·
5,237 Posts
Discussion Starter · #9 · (Edited)
bikerx40 said:
If you can obtain full travel by pushing all of your body weight down on the fork in the DH TST setting then you should definitely add more oil. Unlike a fork like the RS Pike, Zokies are designed to ramp up significantly during the last 20% of the travel. The ramp up is required because Zokies don't use any bottom-out bumpers, and a harsh metal-on-metal bottom-out isn't great for the fork.

IMHO, your fork's oil height should be set so that you use about 90-95% of your available travel on an average ride. This would mean 125-133mm. The last few mm's of travel should be saved for those unexpected casing of jumps or poor technique drops to flat. Pushing for fork down with all of your weight should give you about 85-90% of your travel.

Anyway, make sure you are getting proper sag, and then dial in your oil height and I think you'll enjoy your fork more in the long run.
In addition, the last 10-15mm's of the fork travel will ramp up heavily due to the stiffer spring rate of the ETA spring being compressed.
Fantastic Advice, bikerx40! Just what I needed to know.

From what you say, I may be about right now. At the LBS with only 35 psi they put into the TST and 140 mm travel on the ETA, I was able to get 115 mm (82%) travel just leaning on the fork in the DH TST setting. When jumping on the fork with all my weight, I got to 125 mm (89%). From your description it sounds like I could use a little less, maybe 135 cc's of oil versus 140 cc, but I'm not as far off as I thought. The extra high progression bottom ramp will useful for when I start trying my 3-4' drops and jumps at my huge size and I may just leave it this way for a while.

With my boosting the pressure to 45 psi, I get a sag (in DH TST setting) of 0.8", or even up to 1.4" if I lean forward slightly. With this higher pressure, the fork is just a bit stiffer and slightly less travel than above for the same effort, but it seems good that way. Incidentally, this 45 psi is a lot less then than the pressure indicated in Marzocchi's manual. The manual said even 60 psi in the TST would be too low for my weight, but I find that's way too stiff - I get only 0.6" of sag at 55 psi. I'm beginning to think it's because I have an XL Heckler for stability at my 6' height, and I'm riding more back on the bike, with a short 90 mm stem. Also the bike is more stable with the slack 69 degree head angle of the Heckler, which reduces fork load.

And yet in spite of the slack angle, the fork still pushes down to a low-rider geometry for climbing with the ETA . :) The AM1's a great fork.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top