How To Mod the Vostok 090

Super easy, even for someone that has never opened a watch before. Just make sure you have your basic tools, Modtok 090 conversion case, your Vostok 090 (or any case that features the long crown stem eg, 020, 090, 100, 110, 150, 670) and a Seiko SKX/SRPD compatible bezel and insert. Don’t forget that you can convert any classic Vostok with addition of a long stem.

It takes around 3 minutes!

  1. Remove the caseback of your Vostok
  2. Remove the caseback gasket
  3. Unscrew stem to time setting position
  4. Use a pointed item, eg tweezers to release stem
  5. Place a movement holder over the back of the case and turn the watch over
  6. Lift the Vostok case off the movement
  7. Place the new Modtok 090 conversion case over the movement and turn over
  8. Insert stem and screw in (sometimes you will need to grab stem with tweezers and push the stem in until you hear a click)
  9. Check stem is located by pulling out to time setting position
  10. Refit caseback gasket
  11. Refit caseback
  12. Fit clickspring and your choice of SKX/SRPD compatible bezel and insert.
  13. That’s it, finished!