If it's stamped Type 222 on the crankcase can you identify which bearing the roller came from (diagram attached) or better still a picture of the bearing & where it's from would help, if you can measure one of the remaining rollers with a Vernier Caliper or Micrometer even better.
Where about in the world are you? Webhead or Wallfish may have them if you are in the US or I could help if your in the UK or Europe.