Another stupid bobber question

hehehe, yeah you are right. See, in that photo above if you have a solid cross brace under the fender, you could potentially mount a little seat for a passenger there.

I think I'd be ok with a passenger seat as it is. That tubing is plenty strong, and the fender looks pretty heavy. But yes, a solid piece of threaded tubing to span the fender mounts and bolting in place would certainly be nearly as strong as the original frame.

Good luck, and keep us posted on your progress and ideas. Also, check out chopcult.com. They are more like-minded and lots people over there have performed some quality modifications to these bikes and similar UJMs.