O-ring for sealing the crankshaft timing gear to the crankshaft (MG# 90706250)
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
The size of the O-ring (MG# 90706250) used to seal the crankshaft timing gear to the crankshaft is 25 mm ID × 3.5 mm wide. Viton O-rings are best, but Buna-N work just fine and are a lot cheaper. Make sure to purchase an O-ring that is sufficiently soft...something with a Shore Durometer (A Scale) = 70 is great. McMaster-Carr part number 93125K67 or McMaster-Carr part number 93125K65 would works fine.