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PostPosted: Sat Dec 17, 2011 9:22 am 
Old School Grand Master
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Location: Penarth
Hi
Does anyone have experience setting these up...I have downloaded the owners manual and will re-read it, but I'm a numpty when it comes to suspension.

My forks are virtually new and probably have little air in them. I think I have read somewhere that the travel can be adjusted by the amount of air in the chambers...feel free to laugh, I have no idea what I am talking about.

Anyway. I'm about 15stone and would like to run these at 80mm (they are at 100 at the moment)

Any help appreciated

Ta
Carl


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PostPosted: Sat Dec 17, 2011 12:27 pm 
Gold Trader / rb Rider / Special
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The owners manual is different to the service manual.
I think thats what you will need as im guessing it will be a spacer (put in or left out) to adjust the travel.
How do you know what travel they are already?
Looks like they come in either 85 or 105mm i think.


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PostPosted: Sat Dec 17, 2011 12:48 pm 
Old School Grand Master
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cyfa2809 wrote:
How do you know what travel they are already?


Basically my lbs told me to measure the exposed stantion, and it was 115mm more or less


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PostPosted: Sat Dec 17, 2011 1:48 pm 
Gold Trader / rb Rider / Special
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Relevant info is on page 10 of the manual (a-c).


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PostPosted: Sat Dec 17, 2011 7:01 pm 
retrobike rider
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Also may well be worth sending windwave (the Marzocchi importers) an email for the correct air pressures for your weight - I've got some Marzocchi forks on my 2007 bike and the stickers on the forks were different to the manual so I dropped them a line, to which they replied "Ignore both, do this!" Typically Italian some would say!!


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PostPosted: Sun Dec 18, 2011 9:07 am 
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HB,

I had a pair of ’06 Marathon SL forks, so I know something about travel adjustment on that particular model.
Unlike the user friendly Rockshox Dual Air set up, the Marathons I had were equipped with 4 Air chambers. This IMO makes things rather more complex.

If yours are a similar design to mine, you will need to increase the pressure in the Negative Air Chamber to decrease the amount of travel. Do you have a Shock Pump?

I can probably give more detail on tweaking the air pressure with a picture or Internet link, but can you let me know what the current Axle to Crown measurement is?
If you are looking for 80mm travel, the fork should rest at about 450mm A-C. If they are 100mm travel, they should rest at about 470mm A-C.

It’s the A-C measurement that gives the appropriate Headtube angle for any particular frame – sorry if I’m patronising you now.

I reckon that cyfa2809 is correct with amount travel these forks are capable of – mine BTW were 100mm to 120mm adjustable, but I never did successfully obtain 100mm.

Pip


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PostPosted: Sun Dec 18, 2011 12:23 pm 
Old School Grand Master
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Thanks chaps

The forks are def. at 105mm travel.

Not sure about the chmabers...this is what they say

- 85mm or 105mm Travel
- Open Bath Cartridge
- Dual-Positive Air Chambers
- Negative Air Chamber
- NEW! Cryofit Boltless ’M’ Crown
- NEW! 1-Piece Mg MonoLite Sliders
- NEW! [ECC 5] 5-Position Damping Control
- 30mm Aluminum Stanchions

I don't have a pump yet are the Marzocchi valve adaptor...it's at this point a normally give up and stick rigids on , but it's time I raised my fork knowledge


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PostPosted: Sun Dec 18, 2011 1:58 pm 
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I hope my attempt to help doesn’t just muddy the waters….

You will indeed need a Shock Pump. The Marzocchi valve adaptor is also required in order to get air into one or more of the Schrader Valves.
The manual that I have seen on the Marzocchi site is very confusing – as was the manual for my version. Have a look at this with that in mind;

http://www.marzocchi.com/template/detai ... etto=2434#

If you scroll down to 5.2, there is a poorly written explanation of how to adjust the Negative pressure. I reckon the Left & Right legs are incorrectly referred to in this manual – but onwards.

The Negative Air chamber is smaller then the two Positive chambers, and ramps up quickly at the end of the rebound (extended / at rest) stroke. As you increase the pressure in this negative chamber, it pushes the fork into starting its Compression stroke. This results in the forks sitting lower at rest, or reducing the travel & A-C measurement.

Incidentally, Rock Shox Dual Air set-up, do indeed have a spacer fitted internally to achieve a change of travel & A-C measurement. If I am correct with my assumption, the Marzocchi Marathon SL doesn’t use this method.

Anyway, the Negative Air chamber Schrader valve on your forks should be positioned in the centre of the Top Cap, rather than over to one side. I reckon this is sitting in the Left leg (as viewed from sitting on the bike). The manual, IMO does confuse matters.

See what you reckon HB – let me know if you need me to waffle on some more! We should get this sorted however when you get hold of a pump and adaptor.

Pip.


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PostPosted: Sun Dec 18, 2011 6:52 pm 
Old School Grand Master
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Thanks Pip, much appreciated. There are quite a few suggestions on the mtbr reviews regarding the air pressures.

I'll update when I get a pump and adaptor etc

I have also heard that the amount of oil is important :?


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PostPosted: Sun Dec 18, 2011 7:51 pm 
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Rightyho – I did read the helpful info on MTBR.

If you’re about 15 Stone, I’d start off with about 50 psi in the 2 Positive chambers (Valve holes over to one side) and 100psi in the Negative chamber (Valve hole in the centre).

You’re correct about the oil level, but we can look into that later.

Pip.


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