Page 1 of 1

Fork damper valve ?'s

Posted: Mon Jul 28, 2014 5:56 pm
by tobydmv
What is the aluminum assembly valve in the lower fork tubes purpose? The one with small bearings that sit in vertical ports capped by a washer. It looks like a very ancient rebound valve. Has anyone replaced this stuff with a modern shimmed piston? Seems like it would be really simple to machine a new pumping rod and drop a bolt on piston valve w shims on top. Then create a new plug at the bottom to seal it in. A little semi bath in the fork lowers and your off with real damping.

Re: Fork damper valve ?'s

Posted: Tue Jul 29, 2014 4:32 am
by Jordan
Many old hydraulic forks could benefit from a conversion to more modern damping technology.
You can buy "emulators" for 35mm Marzocchi forks, from Road & Race and elsewhere.
I don't know about earlier Ducati forks. Perhaps you can be the first to develop a good conversion, sell them to keen upgraders, and make a killing!

Re: Fork damper valve ?'s

Posted: Tue Jul 29, 2014 6:31 am
by Eldert
Guzzino sell something like the originals :

http://www.guzzino.com/framechassie4.html

the emulators are made by racetech www.racetech.com/

Eldert

Re: Fork damper valve ?'s

Posted: Tue Jul 29, 2014 3:57 pm
by tobydmv
This is the part below

Image

I believe it is a rebound valve since the washer that sits on top would block the oil flowing down. On the rebound stroke the oil flows up the ports and pushes the bearings against the washer that flexes enough to provide rebound damping. Without it you'd be on a pogo stick as the oil rushes through the port in the pumping rod.

Re: Fork damper valve ?'s

Posted: Tue Jul 29, 2014 10:52 pm
by Jordan
Having multiple bearing balls means the damping can be adjusted I guess, by varying the number fitted.
I had a 31.5 fork where there were fewer balls, and not all the holes were drilled as in this photo.
But another one had the full complement of holes and balls.