Telesco Fork Damping

[Duccout]

I have two Mototrans Ducatis, fitted with Telesco forks, and I am baffled as to how they can produce any rebound damping. When the forks compress, the oil is forced up into the inside of the stanchion, but as they rebound I cannot see how there is any way that the oil is restricted to slow the extension of the forks.

To try to produce some semblance of damping I have progressively upped the viscosity of the oil, until I have reached treacle (SAE 40) which results in very slow movement in winter, perfect damping in mild weather and still no damping at all in the recent hot weather; the forks flapping up and down like a pogo stick. AFAIK the oil is in the forks just for lubrication.

If anyone knows otherwise please post!

Cheers,

Colin