As Ron already mentioned, this is the 322nd bike from contract C/8934. This was a contract for 3000 motorcycles, being 1500 RASC and 1500 RAOC. But this schedule was amended, and "all" the C/8934 bikes (3000 of them) were sent to Feltham (RASC), where (according to O&M and the Chilwell list) they were issued with census numbers C9389001 - 938929 (29 numbers), and C938941 - 941911 (2971 numbers). But on the RASC receipt cards we find 3 blocks of census numbers: C938901 - 938929 (29 numbers), C938941 - 941861 (2921 numbers) and C941887 - 941911 (25 numbers; or 2975 in total), and a note that 25 bikes were transferred to Chilwell (RAOC) after all. RAOC had its own numbering system, it is currently unclear which numbers the 25 RAOC bikes received. Census numbers for this contract can not be calculated, any number around C939240 would be possible / acceptable.
Here are two war time pictures of G3/WO sister bikes with census number C941xxx and C940xxx. Both pictures seem to have been taken in North Africa or Palestina.