Main: FBS9.0 (FRW9.1 for old stock)
Take-up: SBS7.0 (SCY7.0 for old stock)
Counter: SBO7.7 (SCY7.8 for old stock)
I'm rebelting mine now but didn't see the counter belt listed in searches here. The PRB database doesn't list the 920,
restore kits don't mention it, and
ebay will sell you one but what size is it? Russell Industries has a
cross reference list, but the counter belt's Sanyo number is not listed.
I decided to measure it with wire. The path is 8.23"... with an industry standard reduction of 3-5% you're at 7.8-8.0". My old belt's thickness matches SCY7.8 and SCY8.0, which you can still buy as NOS, but freshly made ones can be found as SBO7.7 and SBO8.0. A hair thicker (39 mils vs. 31 mils) but will be fine.