Actually, mirrors whose stem has just one bolt can be converted to a "swing" design, with the addition of three SS washers and one spring washer. Like this (note, this is a CBR600 fairing, not NC30):
Beneath the largest bolt is a stainless steel washer. Further down the shaft of the same bolt, between the mirror arm and the mirror bracket are two more SS washers, with one SS spring washer between them. These washers enable the mirror arm to be rotated through ninety degrees. Easy.
"A slipping gear could let your M203 grenade launcher fire when you least expect it. That would make you quite unpopular in what's left of your unit." - US Army manual of preventive maintenance.
