Marzocchi Fork tube

[Nasher]

My 97 M900 has fully adjustable Marzocchi front forks, and although I know they are not the best they are more than adequate for my needs.

I’ve recently been having issues with a leaking seal on the Right hand side leg.

I replaced it once and it leaked like a sieve, I’ve changed it again for a genuine Ducati seal and it’s better but still leaking.

There are no chips or nicks in the inner leg Chrome, but there is a very small amount of wear on the chrome right at the top of the travel, which is all I can think is causing the leak.
When I rebuild this time I’ll change the slider bushes as well.

My normal source of part numbers etc has let me down as Stein Dinse appear to have all 90s M900’s on Showa forks.

So some questions please to help me search for a replacement inner leg.

Is the inner leg the same on adjustable and non-adjustable Marzocchi forks?

Is the inner leg common to both sides despite other parts being different?

Does anyone have a part number for a Marzocchi inner leg?

Does anyone have one to sell?

And the same question for the bushes.

Thanks

Nasher.

[Nasher]

I'm even more confused now.

I've found part numbers 34910521C RH and 34910531C LH for the fork tubes, but that number appears to apply to both the 40mm Marzocchis and the 41mm Showas!!

Nasher

[Darren69]

It doesn't really help I know, but that'll probably be because it is a Ducati part number and they fitted either Marzo or Showa depending on what stock they had.

[Nasher]

Thanks Darren, and there lies my problem.

Obviously if I order a 34910521C it could turn up as a 41mm Showa one.
I can't find any in the UK and am still plucking up the courage to call Moto Rapido to get the Ducati price.

I've found these:
https://www.carpimoto.it/en-GB/Bike_...rzocchi-40.htm
Which appear to be correct and worth taking a risk on.

Nasher.

[Darren69]

Someones goofed and reused the same part numbers. Is a pair of Showas an option? I assume they will be 17mm axles? But there's likely to be more around as they were used on the 900SS and later 851 too I believe.

[Nasher]

I could convert to Showas, I even have a pair I've already rebuilt sitting in my 900SS project up on my bench. If my MOT was due in the next few days I'd swap them in.

But then I'd need to find another set for the SS, and they are not cheap, considering I'd probably need to rebuild them as well.

I think I might just take a chance on the one in my link above.

Nasher

[Nasher]

I suppose the other question is has anyone successfully removed the bottom casting from one of these forks?

I'm not sure how it's held in place, and nothing I've found appears to show how it's held on, yet the link I posted above shows the tube without a casting.

Nasher.

[Darkness]

The Showa ones can be changed. There’s a small grub screw on the inside and they thread off after you overcome the locktight. A machined split aluminium block is useful to hold them in a big vice and heat and a long bar help!

[Nasher]

Thanks Darkness.

I'm assuming that because you can buy a new leg you can change the bottom casting!

Would be nice to know somebody has done it though.

My plan would be to weld something to the old leg so I can hold it in the vice, then warm up the casting with a blow lamp before putting a lever through the wheel spindle hole to turn the casting.

But obviously every step could damage the casting which I really don't want to do.

Nasher.

[Darren69]

You can't actually see from the picture whether the end is threaded, so maybe as the seller. The Showa ones are but I've never had to change one.

[Nasher]

I popped a question over to the seller yesterday, but haven't heard anything yet.

Probably never will if they are like most companies.

[Darkness]

Originally Posted by Nasher

Thanks Darkness.

I'm assuming that because you can buy a new leg you can change the bottom casting!

Would be nice to know somebody has done it though.

My plan would be to weld something to the old leg so I can hold it in the vice, then warm up the casting with a blow lamp before putting a lever through the wheel spindle hole to turn the casting.

But obviously every step could damage the casting which I really don't want to do.

Nasher.

MotoRapido did it for me on a Showa non-adjustable.

A new fork leg came with a casting attached, but that had a rectangular bar to locate the US reflector rather than the ‘Ducati’ raised lettering. Ten years or so ago Ducati were having a spares clearance and Craig did me a good deal. To keep the detail right I had them swap the casting with the one off the damaged leg.

The best way to hold them is to drill an alloy block to be a tight sliding fit over the stanchion, then saw cut one side so it can be pinched in a large vice.

Edit: this has been discussed before, but the comment #12 here may be a concern:

http://www.ukmonster.co.uk/monster/s...leg#post541560

[Nasher]

Thanks Darkness.

From your post yesterday I've got a work supplier making up an Aluminium block as i don't have anything large enough in my stash.

It would be really nice to try it on a 'spare' leg and casting rather than risk breaking the casting I have.

[utopia]

I'm pretty sure that Dukedesmo swapped fork bottom castings when he built his bike.
Though again, I'm pretty sure that he used Showa forks.
There will be details on his build thread .. though any pics have probable gone down the photobucket tubes.

On the leg clamp, I made one out of a piece from an old, 3x3 fence post ... though it was oak, not softwood, but I would have thought that either would work.
Sorry, I realise this info is too late and you've already shelled out for ally.

[Nasher]

Originally Posted by Nasher

I've got a work supplier making up an Aluminium block

Originally Posted by utopia

you've already shelled out for ally.

Oh you sweet innocent man

Nasher.