Most (or all?) KhVZ frames and forks have a special outer diameter and thread size steerer tube. Instead of the standard 1" they use a 26 mm metric thread.
So, you either use one of the special Soviet head sets, you use a completely different front fork with 1" treading, or you chase the thread with that size.
For the BB set, at least mine, it's kind of same story. Here, the thread size is similar to BC / English, but both sides of the BB shell have RH threads. How to solve this? Well, same as with the head set, use original Soviet parts, chase threads with BC standard or even Italian threads (although the BB shell may become a bit thin, since the outer diameter of the BB shell seems to be a bit less than the standard 40 mm). Another possibility is to use any BB set with BC threading, but not the regular LH and RH cup, but 2 pieces LH cup and lock rings.
The seat tube inner diameter of my frame is 26.2 mm, so the original seat post is not only a nice original accessory for the bike, but it's very convenient, too. Saves me from searching for another post with this odd diameter.
The sizes of the balls for the bearings is another story.
I got the parts for my frame in a plastic bag. There were just 23 pcs 6mm metric (!) balls. These had to fit either the BB set or the headset.
First, I tried to assemble the BB set with "standard" 1/4" balls, but the protrusion of the spindle ends through the cups was far too small. Besides that, the LH cup could be screwed in only half way. It seemed that the 1/4" balls were not correct. This was confirmed by the son of the previous owner of the KhVZ plant. 1/4" is not appropriate, it should be 6 mm. Well, 11 pcs 6 mm balls at both sides seemed to be the right solution. The LH cup was still a bit far out of the BB shell, but given the fact that the bag contained 6 mm balls that may have to fit somewhere and the confirmation by the Ukrainian guy, I decided to stick to this situation. Perhaps 12 balls at each side would also work, but time trialists and track riders prefer to run their bearings with the original quantity minus one. I decided to leave the grease in, as I didn't want it that extreme. And: because I had just 23 balls of the same size, 2x 11 was the best I could do.
The 6 mm balls looked far too large for the (aluminium) head set and that was confirmed by the test assembly. Since most western head sets use either 5/32" or 7/32" balls and I had some 5/32" balls on hand, this was my first try. I think it was a lucky shot. The transitions between cups and cones were very nice and the forks turned well inside the head tube. The seller of the frame already mentioned 4 mm ball size once and he may have been right. 5/32" is almost the same as 4 mm metric.
When I assembled the Shimano Dura Ace track cranks (FC-7600), I noticed that the LH crank touched the LH BB cup. So, the BB axle is a bit too short (assuming that the ball size is correct now). So, I still may have to look into the possibility of another, longer BB set with 2x LH cups. Perhaps a BB-UN90 107 mm will fit, because the cups go deeper into the BB shell.
Just a small note on the seat post. When assembling the saddle and tightening the bolts, I had the strange feeling that the material was a bit weak. I remembered that the round, threaded pieces of the similar style seat post (Campagnolo or SR) also gave problems in the past. Can't remember if the thread stripped or the little round thing cracked. For sure, the rear top part of the saddle clamp developed a crack. It's still on the bike, but I have to wait and see if it will still work or if it will break under my load. I may have to craft a new one (steel?) or use an old Campagnolo small part. The round threaded bit may be replaced by an Ikea part. I didn't check the exact dimensions, but it may fit. Otherwise, it will not be that hard to make it fit.
In the worst case, I can still look for another (Shimano?) seat post, but that will be a shame, since I polished this Soviet piece and it came out extremely well.
