TopTip............ But a cheap 12" x 8" chopping board from a one of those 'dollar stores' or a chapo place at any rate..
drill 2 small holes in the swing arm or if you dont wanna drill use 'NO NAILS' or similar, cut the chopping board to size and glue/ screw on. the polycarbonate chopping boards are a pain to cut, butI use an angle grinder with a diamond tile cutter wheel...... draw shape, cut out, (t melts, and is messy,) but is tougher than anything and will protect your swingarm.
The Honda CT90...... who needs 600cc to see the world?