1000/1200 TriplesThe cam chain is the same dimension as the primary though longer (3/8" x 1/4" x 102 pitches), a single row only, and is an open chain with a spring clip. For this Andy Forsdick recommends an IWIS G67WZ while the Regina C121HCS is also suitable if you can source it.
NOTE:Many years ago (20+!) there was a bad batch of Regina C121HCS cam chains which were not produced properly and ended up "short". These show up by being very tight, having no slack at all when installed. They should NOT be used as they fail very quickly, causing lots of expensive engine damage. Amazingly enough, some of these chains are still showing up from time to time, so be aware.
The twin once again uses the same basic dimension chain (3/8" x 1/4" x 88 pitches), this time in duplex, open with a spring clip. It is crazily over-sized for the purpose but none the less it's a good idea to use the best available product. Andy sells a suitable automotive grade IWIS chain for this.
As an interesting side-note, the chain on these engines is usually very tight on installation and I have found the IWIS automotive product to be noticeably easier to install than some chains I have used previously. A nice product.
The 500 and subsequent Zanč bikes used a very unusual metric chain that is not at all easy to find. In Regina terminology the listed chain for the job was the C107HC. Andy Forsdick is able to supply Regina chains for this application, including the wire-retained joining link. Once again they can be sourced either directly from Andy or in Australia via Redax or myself.