Lambretta engine bump stop washer

Lambretta engine bump stop washer (sits under rubber bump stop)Made by Scootopia
Where do they vanish to? every time I come to build an engine the bump stop washer is missing!

This item is suitable for

TV1 175TVS

series one LI125 /150

series two LI/TV175

series three LI/ TV/ SX200

GP /DL 125/150/200