The bike used in this example is a 1998 Honda XR80R but also carries over to the XR100, and probably the CRF80 and CRF100 too. As you can see, this has CDI ignition so setting the timing for the old points ignition version would be a little different.
The US is one of the only countries using the Imperial SAE sizing system for nuts, bolts, screws, washers, etc. The rest of the world uses the metric system. Metric sizes should be abundant and CHEAP! I found otherwise looking for exact types & sizes for an import auto restoration project. I also learned the hard way about hardness grading.