You would be amazed how difficult it is to purchase valve shims in the MOST DENSELY POPULATED CITY IN THE U.S.
Is there, by chance, anyone in the NYC area (preferably) or anywhere else that has a 2.70 shim and spare exhaust gaskets?
I've got a 2.45, a 2.53x ( unmeasured ), a 2.55 a 2.6 and what I'm pretty sure is a 2.75.
Trade, buy, charity, etc.
Can't help ya with the shims but I got my exhaust gaskets here.....
http://www.partsnmore.com/parts/suzuki/gs500e/?filters[fitting]=custom