35mm Ceriani fork tubes

J

J. Charles

New member
Location
Westminster, Maryland
Hi.  This is my first post on this forum.  A couple of decades ago, I had a 750SF with the stock 35mm Ceriani forks.  I am now looking for longer fork tubes for a set of '70s-era Ceriani Road Race forks, and thinking that the Laverda/Ceriani tubes might work in my RR Cerianis.  TNK (distributed by Race Tech in the US) makes replacement fork tubes for the 1970-72 750 Laverdas that are 584mm long, which happens to be exactly what I need.  However, nobody seems to know, or is willing to check, if the Laverda tubes will accept the RR damper mechanism.  I am hoping that someone on this forum either knows off the top of their head, or else has a 35mm Laverda/Ceriani tube lying around that they can take a look at for me.  To that end, I attached a PDF file with some measurements and photos of my stock, 526mm long Ceriani RR forks.  Not all of the measurements are critical, in that new bushings and pistons can be fitted.  Thanks for any help or insights you can provide.
 

Attachments

I dunno about the RR damper mechanism, but I presume it's something akin to Race Tech gold valve emulators. Laverda 35mm forks (actually Ceriani) will accept gold valve emulators if that's any help.
To confirm whether it'll fit your 'RR' mechanism, you need to know the inside diameter of the fork. I don't have a 35mm Ceriani fork tube that I can measure, but someone here will be able to tell you the ID.
 
Hi Ya J Charles and welcome
If you can wait till the latter part of the weekend then can give you what you need in measurements.
Have a brand new set of tubes and dampers which arrived today and have just unpacked but cant be bothered going to get the Verniers tonight and tomorrow is riding day  :o
Am planning on changing out the fork tubes on my drum brake triple for these flash new ones so if you can wait then will do some measuring for ya .....
now do you want me to do in real measurements or that metric rubbish which will work for you  :o
 
Thank you for your replies!  Dellortoman, I think that Race Tech emulators are just the damper valves, not the rod and piston, but I am not sure.  In any case, I need to source longer tubes before I can even consider new emulators!  Brett, you are a gift from on high.  I can definitely wait for your measurements (I have been screwing around with this problem literally for months, including communications with Frank's Forks, Race Tech, and a couple of UK suppliers).  It doesn't matter if you have "real" measurements or metric ones, whatever is convenient for you.  You mentioned getting new dampers, too.  Would you mind saying who sells those?
 
Hi Charles
it would be great if people would read your question before answering me thinks  :o
The Laverda tubes have the circlip at the bottom of the tube where as the RR Ceriani's run the circlip in a bit from your drawing it seems. Still you might be able to mod the lower spacer.
I sent you some pic's via email, let me know if you need any more info as I have a set of 750 tubes now sitting on the bench  :D and a flash new set of triple ones sitting in the bike
Those RR Type Ceriani's are nice pieces of kip by all reports and the damper set up is way more advanced that the old style ones.. even if you were to throw a set of gold valves at them.....
Good luck
Brett
 
Cam they're not 30mm inside diameter for the complete length you know. Only the first 2 1/8 inches or so.
Note the Lav tubes have the circlip groove at the bottom where the RR ones have it in 10mm looking at the drawing.

inside_fork.jpg
 
I recently cut up a bent 35mm OE Ceriani stanchion from a 750 Lav, I needed a bit of tube and this fitted the bill perfectly for my application.  What I found was that the stanchion is internally reinforced at the point where it passes through the lower fork yoke!  I had always wondered why the spring was such a sloppy fit in the stanchion, turns out it needs to pass through a tight spot lower down...

Checked out a set of pattern stanchions, no reinforcements. ::)

piet
 
This new version of 584mm Ceriani fork tubes are 29.5mm all the way through. These tubes can accept cartridge dampers and modern large diameter springs if required.
https://damclassicracing.com.au/50209882-forktube-35-584mmceriani-t05-0559-gt-sf/

These will also accept the original Ceriani damping components from the Laverda thick-walled forks.

Note: If anyone requires narrow springs for their thick-walled Cerianis DAM Classic Racing had some specially wound to suit in a common spring rate suitable for most road machines. https://damclassicracing.com.au/50120998-fork-springs-for-35mm-fork-6-18-8-73nmm-length-476mm/
 
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