Shamus gets the cigar!
This is indeed the 1989 World Championship, held in Lyon at the vélodrome de la tête d'or.
Here's Ekimov, the only one of the four not to use a disk front wheel:
http://www.flickr.com/photos/nztony/4855824324/
Berzin had only just celebrated his nineteenth birthday.
I think you're correct about the Masi-badged Takhions as well. Masi had begun to supply team bikes to the Soviet road race squad, but as far as I know the pursuit bikes were still built in Karkhov.
http://www.flickr.com/photos/80048824@N00/2267611840/
The photo sequence here shows the unusual construction of the headset, with a conventional lower cup, and a cartridge upper bearing pressed directly into the frame:
http://www.flickr.com/photos/40365317@N ... otostream/
I'd come across the first picture four years ago on the old fixed-gear mailing list and decided that it must have been from the 1989 Worlds in Lyon, but couldn't find supporting evidence at the time. I recently surfed to this photoset, confirming my guess:
http://www.flickr.com/photos/nztony/set ... 641851616/