Yeah, I wouldn't, pavement probably tastes pretty gross. Why not zip tie or clamp (using one of those plumber-style clamps) the bell to the stem?

Besides, unless you have experience tapping, and know how the material will handle it, it takes a little skill (I've never tapped on bikes).

Also, if you have a Technomic, I'm assuming you are a big(ish) guy (I mean height and frame wise, not trying to imply anything), thus the stem integrity would be most important.