I checked the site again to make sure I didn't post something we couldn't reference: http://www.ehobbytools.com/en-us/dept_8.html
This site uses the drill# which also has a decimal equivalent. Most of the kits on that site have the drill sizes we need so it is a good reference. A good kit for us would be one that has Drill#65 to Drill#78 or so. The decimal equivalent of a Drill#65 is 0.0350 and the Drill#78 is 0.0160. Most of the carb jets I have redone on these Chinese 80cc carbs start out around 0.030 and you go up or down from there as you know. I would guess that if you were to drill your jet ( I know you already filed it ) it would be good to step it up 1000ths of an inch at a time. Using Drill#68(0.310) do a test ride and see if the engine runs smooth thru the whole RPM range, if it hesitates on the low end go up one thousands to Drill#67(0.320) and keep going up one at a time until the engine runs smooth thru the whoe rpm range. Then when it feels good riding it - the spark plug will tell you when it is perfect by looking for a light brown to grey color on the electrode. Black and sooty sometimes wet=too rich. Hope this helps
I will go online now and buy one of there drill sets. I hated using the file method but I couldnt wait. I figure I have 2 options if I went to big with the file I will follow your instructions for resoldering the hole and starting over or Ill pick up another set of jets. I do have a couple other motors here now since Im now selling the 70cc 2 stroke kits so I can always pull the jets from another carb if need be till I get the new parts In. This information has been vey helpful. Im trying to learn as much as I can about these kits and do my own experimenting before I get out there and start really promoting these kits. I would hate more then anything if I had a customer calling me saying we just bought one of your motors and they dont run worth a ---- well you know what im saying and I didnt have anyway of offering them help. Thanks again.