I cut mine off my CB500 and CB550.
I haven't done it yet on my bikes, but you should make sure you replace the fender stay with some kind of bracing behind the shocks. A flat bar welded across ought to work (so long as your tire won't hit it), or a hoop like this:
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-chassis-seat-parts-rear-steel-hoop-section-tail-dcc-cb550750diytail.html