bclapham,
I saw your post but with out a 6mm mill and a drill press I decided to try it myself. I'm also more of a learn by doing, now that I've done it your post is very clear, before that it was not so, no matter how clear you actually were../..anyhow,,,I think I may be ok...the metal was thin, but I could not punch it through and I assume there is little pressure at this point. I'm sure I will be in there again making more mods. I found some .1 shims to use on the base valve. For now I have removed 1 ea. of the ones yamaha doubled up on this year and also removed 3 of the LSC 27 dia shims. If this doesn't make this baby plush I will try the .1s and remove 1 or two more of the HSC shims...by the way since this is a single stage what shims would be considered the LSC vs HSC?......Also, how would I use an oring below the peened area if I open them back up and notice the metal has punched through? This area was all threaded if I remember correctly. Thanks AGAIN!