Elaine (Vech's SO/Wife/Partner) has her own web page on how to adjust /2 valves. You can find it here:
No direct link as they have finally updated their web site! Look under "Tech Advice" on the left and then "Technical and How To". There is a wealth of knowledge and information there.
Pastor, Church of the Horizontally Opposed Air Cooled Twin
'66 BMW R60/2, '83 BMW R100RS,
'81 BMW R100RS "Das Beast", '77 Honda XL125