Atomizer O ring size?

[LaMojo]

for PHBH30.  Finally getting around to the V65C that's been languishing around in the garage for 2-3 years.  Bought a new battery about a month ago.  Received new petcock gaskets from Bruce Giller a couple of days ago,  cleaning tank and carbs today.  Had a hell of a time getting the float bowl off because of the trashed O rings.   Anyone know what size I need before I go to the auto parts house?  Thanks.

[Antietam Classic Cycle]

http://www.thisoldtractor.com/moto_guzzi_loopframe__for_sealing_the_carburetor_enricher_jet_to_the_float_bowl_-13936100-.html

[LaMojo]

Thanks for the link Charlie.