Update: I did two things, 1. I ordered a set of numbered drills from Amazon which showed up one day later, and 2. I called and emailed BE.com who had one in a carb the Tech was canabalizing.
I soldered the old jet and drilled it with a #72 bit. Too lean according to my plug chop. Redrilled with a #70. Lots better, but maybe still a little lean. Now I'm waiting for the stock jet to show up so I can used the hole size on it as a source for comparison.
A note about soldering the fourstroke jets. The metering hole in these jets is about halfway through its length. It can't be reached with a soldering gun so a large portion of the jet body has to be heated. The jet also has a cupped portion that seals against another brass metering section. It's difficult to keep the solder off this mating surface.
To further complicate the situation, there are multiple gaskets between the carb and the head. Each of these gaskets is an opportunity for an air leak. Air leaks will cause a lean condition. To seal the gaskets effectively, I used a technique I learned working with old Vespas. Grease, just good old bearing grease, smeared on the gaskets will provide a very good seal and make dissassembly a snap. RTV sealant works well but makes further service difficult.
Lots to learn about these little guys.
