Problem fitting damper assembly after rechroming stanchions

M

Mike_P

Junior member
Location
North Yorkshire UK
I’ve just had the 38mm Marzocchi forks on my Jota rechromed by Philpotts as they come highly recommended. However, on receiving them back & trying to reinstall the damper assembly, it just won’t go in, the inside diameter must be less than it was. Has anyone had this issue previously ? Obviously I will speak to Philpotts, looking on google I can’t find any other folks that have had this issue, I’d assumed the inside would have been plugged off to prevent this
 
I've had 2 sets of fork legs rechromed by Philpotts for previous projects and never had an issue with their work,thats not to say though that something could have gone amiss with yours though unusual.

Have you measured up both internal diameters of both legs...?.....is there an inner burr stopping re assembly?.....are you re assembling them correctly (gotta ask).....good luck,keep us posted.
 
I have a brand new set of damper assemblies having bought a set of new Marzocchi legs and internals from Laverda Paradies. The stanchions are the originals though and neither the new set or the old set that did fit will go in….no visible burrs, rather frustrating.
 
Mike_P said:
I have a brand new set of damper assemblies having bought a set of new Marzocchi legs and internals from Laverda Paradies. The stanchions are the originals though and neither the new set or the old set that did fit will go in….no visible burrs, rather frustrating.
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Maybe a MetalLathe could help?

Rainer
 
Mike_P said:
I’ve just had the 38mm Marzocchi forks on my Jota rechromed by Philpotts as they come highly recommended. However, on receiving them back & trying to reinstall the damper assembly, it just won’t go in, the inside diameter must be less than it was. Has anyone had this issue previously ? Obviously I will speak to Philpotts, looking on google I can’t find any other folks that have had this issue, I’d assumed the inside would have been plugged off to prevent this
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I believe that Philpott's have a good reputation. If so will rectify things if they have caused you issues.

Surely a visual check inside the stanchions will reveal whether that have received hard chroming?

Many years ago I sent a slightly bent pair of Cerianis to HCPG (Hard Chrome Plating & Grinding). Unfortunately during the process to strip the previous chroming both tubes cracked along the welding seam. HCPG asked me to send my internals so they could make me a new set of tubes. These are still perfect 30 years on :)
 
The damper pistons can grow in size from internal corrosion as they are made from Mazak metal which is mostly zinc. Impurities in the zinc (usually lead) will make them grow over time. Even new damper pistons sitting on the shelf can be too big from this. Don't bother turning them down as it will only be a temporary solution. You need new ones made from aluminum.
 
1200ts said:
The damper pistons can grow in size from internal corrosion as they are made from Mazak metal which is mostly zinc. Impurities in the zinc (usually lead) will make them grow over time. Even new damper pistons sitting on the shelf can be too big from this. Don't bother turning them down as it will only be a temporary solution. You need new ones made from aluminum.
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I believe it's only Ceriani pistons that can expand like that. I'm happy to be proven wrong but I've never heard of Marzocchis doing that.
 
Many thanks all for the replies, I’ll take some measurements and have a closer look over Christmas. Just to add that I’m very happy with Philpotts and I know that they’ll resolve it if the issue turns out to be on their side.
 
Well it looks like the problem was they had engraved my name on the inside face, part of the lettering was just raised enough to cause a problem…I just tickled the face slightly over the letters and they go in.
Next problem, does the seal orientation make a difference ? See picture….on the brand new assembly (top one) that came assembled it’s orientation is different to the old ones in the bike (bottom)….advice appreciated as usual
 

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That’s brilliant many thanks for that link, really useful. I imagine the piston orientation likely doesn’t matter then although they did reverse it for some unknown reason
 
I knew there’d be something else !
Any tips for getting the nylon ring over the edge inside the stanchion ? The piston fits over nicely but the blooming nylon ring keeps snagging ! I should be doing Christmas stuff I know 😊 but I want these forks back on
 
Note from manual…
Carefully insert the damper assembly into each stanchion,it is advisable to use a sheet clamp to ensure easy installation and to avoid any risc of ring breakage.👍

I would think from memory it is like a piston ring which needs help compressing it ie closing the gap in order to allow it to pass into the bore,then allowed to expand with the clamp removed 😎
 
Schurminater said:
Note from manual…
Carefully insert the damper assembly into each stanchion,it is advisable to use a sheet clamp to ensure easy installation and to avoid any risc of ring breakage.👍

I would think from memory it is like a piston ring which needs help compressing it ie closing the gap in order to allow it to pass into the bore,then allowed to expand with the clamp removed 😎
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Many thanks. I understand the principle but it’s buried deep inside the stanchion when it needs compressing, at least with engine pistons they’re accessible to compress. Am I better feeding this in from the top of the stanchion then I wonder
 
Not to hijack this thread, but is rebuilding (or checking) the internals of Marzocchi forks on my 750 SF2 w 18K miles a good idea, and will it improve the fork functionality? So far, I've changed the oil twice and the forks seem to be working OK. The old oil was very black and the springs didn't have much wear on the sides of the coils. Just curious-
 
I think you'll find they are Cerianis. With 18k miles they should be in great condition. If seals are not leaking leave them alone. I strip mine every so often just to clean them. Really not much to wear out internally.
 
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