I've considered just drilling a hole in the side cover and screwing an extension the original valve. Anyone see any reason why this wouldn't work? Opinions on how bad it would look?
I second that idea... Put a chrome cap on it and call it done!
I'll chime in...
If you're talking about a straight, solid, metal extension -- the kind that you can find, say, to add to car tires, when the short valve stems are buried in hubcaps -- I don't think it would look too bad. Get the hole aligned properly, put a big rubber grommet in the hole, and I think it might make a good mod.
Potential drawbacks: I think it would be difficult (but of course not impossible) to get that hole aligned; it might be difficult to find an extension long enough; and, at least on Cross bikes with saddlebag guards, I think you'd come out right behind (between) a bag guard downtube and the cover, which would make attaching a pump hose somewhat of a problem.
If you're talking about adding just a flexible hose sticking out a hole in the stock filler area, I think that wouldn't look very good (and I'd instead duplicate MTVic's work, ending out front).
Of course, there's no accounting for taste, either, so this is probably a touchy subject... certainly a subjective one. I added a Powerlet socket through
the left side cover, and one reader called that a "mutilation" of the cover, whereas I think it looks very nice. (BTW, mayonnaise played a big role in my aligning that Powerlet hole; see http://www.billanddot.com/victory-xc...in-side-cover/