How to soften Marzocchi DJ3s (2008)?

F

freddofrog

Likes Dirt
Hi there

Did a search but seems I have the opposite problem to most. My son is 20kgs and these are barely moving under his weight. Marzocchi don't make a softer spring for them so is there any other way I can soften it?

Am I able to get a softer spring from somewhere else and just cut it down to size?

I did a ghetto stretch and chop on his little 20" MTX 150 spring which worked fine but something tells me doing the same for "proper" 26" forks is not a good idea.

btw I am looking for a different fork but given my very limited budget I may be looking for a long while.

Edit: btw it does not have air adjust like some other DJ3 :(
 
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redbruce

redbruce

Eats Squid
freddofrog said:
Hi there

Did a search but seems I have the opposite problem to most. My son is 20kgs and these are barely moving under his weight. Marzocchi don't make a softer spring for them so is there any other way I can soften it?

Am I able to get a softer spring from somewhere else and just cut it down to size?

I did a ghetto stretch and chop on his little 20" MTX 150 spring which worked fine but something tells me doing the same for "proper" 26" forks is not a good idea.

btw I am looking for a different fork but given my very limited budget I may be looking for a long while.

Edit: btw it does not have air adjust like some other DJ3 :(
Click to expand...
Your "stretch and chop" exercise will increase the spring rate.

You might get away with stretching a cheap spring but do that on a properly tempered spring and you destroy the temper and it becomes a piece of coiled soft wire (no longer a spring).

If you have the specifications of the OEM spring, you can get one made up at a spring works at a lower rate.
 
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moorey

moorey

call me Mia
I know its more money, but I found the only decent option to be an air fork. 7yo son has dual air forks running at about 25-30 psi. They are plush as, and only bottom out if he lands hard on the nose...and every month or so, whack another bit of pressure in. His spinner forks on the old 20" bike were as soft as a coil fork could be, and still never moved more than 10mm unless I pushed them down...
 
tomacropod

tomacropod

Likes Dirt
I can't remember if this fork uses the sun tour nitrogen cartridge in the left leg or not. If so, it may have seized, this is a common problem with these cartridges.

- joel
 
brendonj

brendonj

Likes Dirt
Do they have an air valve on top? If so you could try with no spring and just air pressure - ghetto air spring kind of thing.
 
K

kalem

Likes Bikes and Dirt
I remember seeing a picture of a morewood downhill bike in south africa that had it's shock spring machined down on the external circumference, to remove material and therefore decrease the springrate, from what i remember it was to achieve a small adjustment in springrate because they had trouble getting a good variety of springs..

Might be too minor an adjustment for what you are looking for though...
 
F

freddofrog

Likes Dirt
An air fork would be ideal but realistically it's out of my budget for now.

Not sure what's in the left fork. It has some weird cap so can't take it off to have a look. see pic

I'm going to look at an extra soft Fox 36 spring tomorrow ($20). I can cut it down to size but it's also about 2mm in diameter smaller. That will mean the rubber thingy (elastomer?) in the centre of the spring won't fit. At this point I don't think it's a big deal as we're only doing XC so it's not likely to bottom out. And as it's always under at least some kind of compression, I don't think it will rattle around.

What do you think, will it work?

DJ3 Fork LHS.JPG
 
P

poita

Likes Dirt
Are you sure that cap on the left fork leg doesn't unscrew to reveal a valve?
I was profoundly confused as a kid when I couldn't find the valve on my air sprung dj3s only to have someone unscrew a cap looking like that in front of me!
 
B

BKelly

teh fast
Is there a preload adjuster on the right hand side?

If so undo it and pull out the spring, there is usually an elastomer (rubber) bumper inside the spring, when removed the fork will be less progressive and easier to get full travel.

If then it is too soft you can try cutting down (would suggest 10mm at a time) the elastomer and re-fit.

The left side pictured is the damper and is not adjustable in any way..
 
redbruce

redbruce

Eats Squid
freddofrog said:
An air fork would be ideal but realistically it's out of my budget for now.

Not sure what's in the left fork. It has some weird cap so can't take it off to have a look. see pic

I'm going to look at an extra soft Fox 36 spring tomorrow ($20). I can cut it down to size but it's also about 2mm in diameter smaller. That will mean the rubber thingy (elastomer?) in the centre of the spring won't fit. At this point I don't think it's a big deal as we're only doing XC so it's not likely to bottom out. And as it's always under at least some kind of compression, I don't think it will rattle around.

What do you think, will it work.
Click to expand...
You say the Fox is 2mm smaller in diameter, but you also need to measure the wire diameter and number of coils per unit length and compare that to the Marz spring.

All things being equal, reducing the coil diameter stiffens the spring, as does increasing the wire diameter and having fewer coils for the same length (they are all interrelated and so must be looked at as a whole).

Might pay to check first or else you are another $20 down and no closer to the desired result.

On the rubber bumper, this is a bump stop. If you are getting insufficient travel to engage it, removing it will do nothing.

At 20kg and assuming 60% weight on the front to achieve full travel (75mm?), you need a spring rate of around 1.6kg/cm. That's very light and I doubt any Fox 36 spring is going to be that light given the forks intended purpose. The lightest Mazochi spring listed for the 66 and 888 models appears to be 2.7kg/cm.

http://www.marzocchistore.com/Templ...IDFolder=610&IDOggetto=73954&IDArticolo=54350

Also at over 2.7kg, the DJ is a bit of a boat anchor for a 20kg kid. I'd look around for a second hand Manitou R7 (1300g) or Skareb air. You will pick one up for around $100 (second hand 80mm travel).
 
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0

0psi

Eats Squid
^^^ This.

And just because I like seeing little fellas out on the trails I'll chip in $20 to the "Sell the DJs to buy some R7s" fund. Anyone else want to help a future pinner out?
 
moorey

moorey

call me Mia
0psi said:
^^^ This.

And just because I like seeing little fellas out on the trails I'll chip in $20 to the "Sell the DJs to buy some R7s" fund. Anyone else want to help a future pinner out?
Click to expand...
Good call. I'll do the same to see the kid on a ridable fork. Its made a world of difference to my lad.:kiss:
 
F

freddofrog

Likes Dirt
Gee thx guys, very nice of you.

I managed to pull off the lhs fork and its just a damper, I think, definately no air.

Thanks for the advice on the Fox 36 springs. Never thought of all those factors. I was just going to squeeze them and I they were a lot softer go for it. Sounds like its not going to be soft enough. I'll let you know in a few hrs.

I went to a spring manufacturer this morning and its $125 for custom spring! They had some other left overs for $5 bit nothing suitable :(

Did a quick search for a Manitou R7, no luck but at least I have something to keep an eye for.
 
0

0psi

Eats Squid
Now we just need to find a someone with a suitable air sprung fork they're willing to part with at a decent price :high5:

Edit: Damn simultaneous posting! ^^^ Good find.
 
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