My old CB900Custom had the little tool thingamajig for pressing the valves down. It was easy to swap shims. I did a lot of research and sperimenting and finnaly came to the conclusion that you MUST pull the cams, end of story. The shim buckets do not have enough meat to grip enough to press down with even a custom made tool.
This is the honda tool:
available
here if you want to try it yourself.
Chy, you will need one for the 650custom too I believe.
