Marzocchi stanchion tube scarring?

[noobi]

Hi,

there appears to be black scarring on the stanchion tubes of both my 07 marzocchi forks, any one know what the deal is?

thanks

[wence]

Originally Posted by noobi

Hi,

there appears to be black scarring on the stanchion tubes of both my 07 marzocchi forks, any one know what the deal is?

thanks

Yeh mate,
Gas gas has a problem where they have bushes in the forks which are a tad too tight.
They grab on the fork as the fork flexes.
I just had my shock and fork done by a renowned suspension tuner and he said it was a common problem with the gg forks.
He revalved the forks and shaved the bushes and the forks are now bloody awesome.
Shock had a service and feels great too, like a new bike.
Cheers Mark

[Klausen]

as gas has a problem where they have bushes in the forks which are a tad too tight.
They grab on the fork as the fork flexes.

that's very interesting my black coating GG 250 2006 becomes also thin on some areas. I think this is also normal erosion.

But when I fix the fork with the bottom in a vice, I feel some clearance between inner and outer tube.

Therefore I fit some precision metal band (0.02-0.05mm) between tubes and upper bushing to reduce this clearance.

[iancp5]

Originally Posted by wence

Yeh mate,
Gas gas has a problem where they have bushes in the forks which are a tad too tight.
They grab on the fork as the fork flexes.
I just had my shock and fork done by a renowned suspension tuner and he said it was a common problem with the gg forks.
He revalved the forks and shaved the bushes and the forks are now bloody awesome.
Shock had a service and feels great too, like a new bike.
Cheers Mark

Do you happen to know how he shaves the bushes?

[webmaster]

Sorry to disagree - but the trick of modifying the bushings was done on another brand of fork (showa) to fix a problem that this fork had - insufficient overlap. Applying this mod to every brand of fork has no effect other than the one called "placebo". Great improvements in fork action are due to great valving.

There are two issues -

1. The Ti coating on the fork tube is extremely thin and wears off rather quickly - looks cool at first though. No big deal - only cosmetic.

2. The upper tube wall thickness is thin so care must be taken when tightening the pinch bolts on the lower triple clamp. If over-tightened the lower tube will be slightly deformed and bind - you will see indications of this on disassembly where the hard coating has been worn off on the upper tube in this location.

Jeff
Webmaster
GasGas Riders Club

[wence]

I am not sure how he shaves or fixes the bushes but he said it was a common problem with the Zokes forks(45) on the gassers he has done.
Gas gas evidently knew of the problem but kept denying that that was what it was, who knows?
I am happy with the work anyway and am sure there wont be any more black coating dissappearing as he stands by his work and basically guaranteed the problem was fixed.
Cheers Mark

[GMP]

Jeff is correct. We have discussed this before, and member pobit had modified a set of his forks as an experiment with no noticable improvement. What that tuner in Austrailia does is cut the edges of the land in the tube so the bushing can float or rock from side to side. Remember that there are many theories and ideas out there but not all are correct. Excessive triple clamp bolt torque is the biggest contributing factor to poor action. Huskys I've seen are particularly too tight from the factory. I work on my brother's '02 Husky Zokes for him. In all that time, the bushings are still good, the teflon coating is still intact. I would not expect this to be the case if there were a binding problem from a design flaw. I suspect the improvement you feel is from the revalve.

[wence]

Fair enough,
I was just saying what he told me.
I guess his fix stops the rubbing though? or not?
You are right in that the improvement is from the revalve, I was never trying to say his fix for the black coating rubbing was what improved the suspension. All good anyway , sorry to lead you astray noobi.
Cheers Mark

[GMP]

Actually the intent of that that "fix" has nothing to do with the coating wearing off the lowers (which is normal). The idea is that if the fork flexes, it will allow the lower tube to move slightly without the bushing binding or "cocking " in the upper tube. Its just an idea, I say show me some data to back it up.