horizontal honda engine valve adjusting video here
IIRC it's windows media player format, some folks had trouble viewing it
it's on youtube, too (lower quality IIRC)
try this:
or this: YouTube - How To: Adjust your valves
easiest, least intrusive way would be to get one of these
description and picture pilfered from http://www.chicagolandmgclub.com/members/tool_lend.html
pretty commonly available from tool rental places