# dirt jumper fork tuning



## da_eddio (Sep 23, 2006)

tried posting for advice a while back in the "lets talk about shocks" forum but didnt really get much help, so figured seeing as nearly all the people here have had some experience with them it might be a better place to ask!

right, fork in question is a 2003 dirt jumper 2. i realise there isnt much to do in the way of 'tuning' as such, i just want to stiffen it up without paying for new springs (dont see the point as their £30 and the fork is barely worth that hehe). 

first idea ive had is swapping out the oil to a heavier weight, it probably has a 7.5 in at the moment and figured id try a 15. 

also i wouldnt mind limiting the travel but without taking a grinder to the springs and lowering it that way, so i was wondering if i overfill the oil above the reccommended amount, will this prevent the fork going through all the travel and also might it cause problems i.e. fork exploding!

and finally would doing all the above, and adding more air preload than the 15psi max reccomended risk blowing it up to give it a stiffer feel?

ooooooook, think thats it

cheers lads


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## JBsoxB (May 18, 2004)

ask brad at nemesis project, i know he knows marzocchi forks.


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## asianprideryder (Apr 21, 2007)

i second that.
brad will do u a kick ass job on that marz fork


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## da_eddio (Sep 23, 2006)

maybe i should mention im in the uk, so sending a fork out to him might not be the most cost effective thing hehe, but thanks for the suggestion anyway


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## XSL_WiLL (Nov 2, 2004)

More oil means you're less likely to bottom. You won't get full travel. But why? If the fork is still going to be as tall as it was,, you might as well use all of the travel.

A more viscous oil will only add damping. It will add compression AND rebound. Marzocchi ships with 7.5wt Golden Spectro. If you use another brand's 15wt, it may actually be less viscous than GS.


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## da_eddio (Sep 23, 2006)

the main reason i want to avoid lowering the fork but limit the travel is that i dont need it all for the riding i do, and to lower it wouldnt be a good idea as im 6'4 and i would feel far to hunched over, i just want to stiffen it up and take away the massive dip in travel, if that makes sense hehe.

thanks for the suggestion of golden spectro, i will try to look for this particular brand!


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## snaky69 (Mar 8, 2005)

Add more air, those forks can easily hold over 50psi. the recommended 15psi per leg is already very very stiff. I'm running 5 psi(approx) in each leg on my tuned Z1 and I'm only getting all travel on big drops to flat(don't do those often, but they're fun to hit once in a while) and on bigger jumps. I weigh 155lbs.

Adding thicker oil will slow rebound and compression stroke, can be nice or not, depends on how you like your fork to feel. Adding too much oil will prevent bottoming out and limit travel, but hydro lock can potentially be damaging to the fork's internals.

Lowering the fork won't make you feel hunched over, you don't need to go down to 60mm, just 80 is fine and it won't change your riding position much, if anything, get higher rise bars to compensate and enjoy the steeper head angle!


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## da_eddio (Sep 23, 2006)

the fork is already set at 80mm, and im working on finding some 3' riser bars too to help compensate the 24' wheels. 

thanks for giving me some info regarding the forks psi tolerances, most id gone to was 25psi, glad to know i can go higher 

what would be a safe amount of oil to add to limit travel, without having hydro lock and wrecking the internals?

also does anyone have any info on how much oil the fork should have normally?


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## XSL_WiLL (Nov 2, 2004)

I still say there's no point to limiting the travel via hydrolock.


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## *micke* (Aug 8, 2005)

I've owned and tuned a bunch of 'zocchis and I'd suggest the following if you're into doing your own wrenching:
1) Change to a slightly higher wt oil to up the compression damping a bit. I'd start with 10wt Golden Spectro.
2) Raise the oil level _slightly_ to make the fork ramp up more towards the end of the stroke. Start with Marzocchis recommended amount/level and add a little at a time until desired progressivity is achieved. A bit of pita but well worth it when you get it right.


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## da_eddio (Sep 23, 2006)

has anyone got any specific measurements for how much oil to use in either fork leg so ive got a starting point?


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## snaky69 (Mar 8, 2005)

da_eddio said:


> has anyone got any specific measurements for how much oil to use in either fork leg so ive got a starting point?


Check the marzocchi online user manual.


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## da_eddio (Sep 23, 2006)

tried searching the entirety of the site for things for the 03's dj 2 but found next to nothing for all my efforts, which was a lil annoying


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## snaky69 (Mar 8, 2005)

Just download it for the current DJ's, the internals are nearly the same and I think they need the same amount of oil.


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## Ryan! (Sep 19, 2007)

Why not just put some "bushings" in the forks which will give you more compression?


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## XSL_WiLL (Nov 2, 2004)

Er.. I think you mean elastomers...

Oil dissolves elastomers.

Bushings are what's pressed into the lowers to keep everything tight.


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## *micke* (Aug 8, 2005)

From the Marzocchi site:

Fork Rider weight
55-80 kg 80-90 kg
Dirt Jumper 2 Ø32 c.110 155/155 160/160
Dirt Jumper 2 Ø32 c.130 155/155 160/160
Dirt Jumper 2 MQR20 Ø32 c.110 155/155 160/160
Dirt Jumper 2 MQR20 Ø32 c.130 155/155 160/160
The table shows the oil volumes in cc. The first number refers to right leg, the second number to left leg.

From this table:
http://www.marzocchi.com/spa/mtb/products/oillevel.asp?LN=UK&Sito=mtb&Y=2003


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## Ryan! (Sep 19, 2007)

No, I ride dirt bikes also, and if we want a cheap easy way to stiffen our forks we go to a engineering company who will make us some metal bushes to stiffen the spring!


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## da_eddio (Sep 23, 2006)

thanks for that info micke, ace find!


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## XSL_WiLL (Nov 2, 2004)

Metal does not really compress.... Bushings are used to reduce friction or wear or to restrain motion of mechanical parts.


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## bringdoom (Sep 1, 2007)

Ryan! said:


> No, I ride dirt bikes also, and if we want a cheap easy way to stiffen our forks we go to a engineering company who will make us some metal bushes to stiffen the spring!


I ride mx also, bushings wont stiffen springs, your thinking of shims. Add some shims to the end of the spring and it will compress the springs more, loose that amount of travel but the extra force put on the springs will help keep it from compressing so fast.


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