Steering Head Bearing Washers

[Davo]

Just looked at my Laverda 1000 spare parts manuals for pre '76 and '76 and both show the lower external "Bearing cap" - p/n 33270004 55. Laverda Paradise also has an external cover on the upper bearing - I assume that is for the Marzo forks/yokes rather than the Ceriani ???

 

[Lav the impala]

The seal is obtained when the leading edge of the seal, rotating under slight pressure, laps the surface of the inner or outer bearing ring. This lapping process creates the sealing surface which keeps grease in and contaminants out of the bearing.

During the run-in process, microscopic metal particles are formed and deposited on the outside of the sealing lip. Those particles that do migrate into the sealing area are trapped in the grease within the recessed area so as not to affect the bearing's performance

 

[sfcpiet]

The seal is obtained when the leading edge of the seal, rotating under slight pressure, laps the surface of the inner or outer bearing ring. This lapping process creates the sealing surface which keeps grease in and contaminants out of the bearing.

During the run-in process, microscopic metal particles are formed and deposited on the outside of the sealing lip. Those particles that do migrate into the sealing area are trapped in the grease within the recessed area so as not to affect the bearing's performance

At least that's the theory behind it...

Works, to a degree.  Bikes subjected to a lot of bad weather riding often show corrosion within the lower bearing.  No way to tell afterwards if water has ingressed through the seal cap or has trickled down from the top.

Head bearings just don't last forever, no matter what you do to try to preserve them!  Well, they do on most Ducati bevels... (bolt)

piet