The hole is not 0.03125 inches larger, its in mm. This is only about 1.6% larger in terms of area. I doubt Dave determined the proper hole size to that level of precision. For what its worth, before I moved to an FCR carb I did Dave's mod on my CV carb with a 4 mm drill, it seemed to work fine. +1. I saw in Dave's post the numbers is mm but he mistyped the measurement unit in inches. Now the possible confusion should be ruled out. I haven't done the mod yet, but will do it when I have my air filter and my jets. Hey I'm curious if you would want to do a trade? I would love a set of metric drill bits.. would you be interested in a trade for a set of SAE bits? Are you telling me you can't find a metric set anywhere in California? I doubt a trade will be worth while as the postage between here and there would be killer expensive. Anyway, I really don't need an imperial/SAE drill bit set.