Camshaft thrust plate (MG# 12054000)
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
The camshaft thrust plate bolts to the front of the engine block, inside the timing chest cover. This flange is subject to wear in two locations. On the rear facing portion of the thrust plate, the camshaft may wear a slight groove. On the front facing portion of the thrust plate, the camshaft timing gear may wear down the front face.
I have never seen any specifications regarding the overall thickness or wear limits associated with the camshaft thrust plate. A new camshaft retaining flange measures 6.91 mm - 6.92 mm thick. I would replace with new if I observed any indented grooving on the rear facing portion or if the overall thickness had been reduced by a meaningful amount. What is meaningful? I'm not entirely certain. I can tell you that I chose to replace a camshaft thrust plate that measured 6.4 mm thick and which did not have an observable indented groove on the rear facing side. 0.5 mm wear seems plenty to me.
Thanks to Ralf Brinkmann for providing the following information on the Yahoo! Loopframe_Guzzi news group. In Ralf's own words:
HMB Guzzi send me this information 4 years ago:
Ich würde sagen 1⁄10 mm kann man tolerieren.
Translated from German to English using Google translate:
I would say 1⁄10 mm can tolerate.
Fortunately, replacement camshaft thrust plates are readily available at this time. See MG Cycle part number 12054000.