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I have a KHS Montaña Comp mountain bike with 26" wheels. It has a Marzocchi fork that is completely shot, both left and right side of the fork.

They hold no air, even spews oil and air if I move the suspension with my hand.

I looked up youtube videos about refurbishing, but in the videos, the top has a hex-nut that lets you take out the valve, but mine do not have that. I'm afraid that refurbishing this model Marzocchi is beyond amateur mechanic level? Professional refurbishing is probably expensive?

Since I use the bike for street riding, I want to replace it with a rigid fork. And I wonder if I can just replace the two bottom legs from a springed tube to a simple rigid tube that holds my wheel?

That way, I don't have to take off the entire fork assembly.

defective fork

Or do I have to completely remove the whole thing, where it attaches to the steering and the frame?

I think the Marzocchi fork is an after-market part, I bought the bike used, and I don't think this bike came with one from the factory.

They look pretty hi-tech though, they have some dials at the bottom going 1-2-3-4 which the Marzocchi forks I see online do not have. Not sure what they are for, damping or stiffness setting?

Oh, and the bike has a rim-brake, which I guess complicates the whole matter even more, as not all forks support that?

UPDATE: I measured the Stanchions to be 24mm, and it appears that the model is Marzocchi XC500.

  • I've always wondered if one couldn't "lock out" shocks by buying a length of PVC drain pipe, slicing it in half lengthwise, and clamping the pieces around the shock pistons. – Daniel R Hicks Jan 15 at 23:11
  • @DanielRHicks I like your idea! If during use it turned out that PVC was not strong enough other options might be to use some steel tubing with the correct inner diameter or maybe drill a hole through the body of the fork on each side and put in a pin/bolt on each side to make it solid. – David D Jan 16 at 14:56
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It wouldn't be a "simple rigid tube", because it would have to include dropouts and brake mounts. And it would also have to fit into the existing fork's crown. Where would you get such a thing? I don't think Marzocchi, or any other manufacturer, makes it. If you're handy with a welder, you could fabricate it yourself - but at that point, you might as well just make a whole new fork.

Just replace the fork. It's not difficult. Make sure that the crown-to-axle distance is similar to what you had before, otherwise it may screw up the handling.

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  • Thanks. Yeah, I replaced it. But it wasn't straightforward. After spending $60 on the fork, they needed to mill it to make a crown fit at $35, followed by adding thread to the steerer tube at $45, as it had too little thread. A very expensive operation unfortunately, for a low-end bike. Lesson learned. – Bram Jul 10 '19 at 0:00
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Just buy a suitable rigid fork from the decade, should be around $20. The dimensions for the fork can be found in this document, reproduced here: From link provided.

Yes, this fork is a Marzocchi XC500 - a well known air/oil suppension fork from around 1994. It has usualy a 1 1/8" steerer, also 1 1/4" have seen, steerer dimension are here. It is almost easy to service it, you can find a manual and spares around here. This fork needs to be open from the top by letting the air out, pressing the top air cap in and release the circlip out.

The knobs in the bottom are for damping adjustments, 1 is somehow soft, 4 is more stiffer (oil runs through smaller holes inside the damping unit).

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