Hi mate
I did a mates '85 cr500 caliper with a seized pin last week.
The allen head was rounded so i drilled down into the pin shaft and inserted/hammered an 'ezyout' into the hole.
Still no move , even with a big shifter on the end of the 'ezyout'! (careful -you do not want to snap off an 'ezyout' in the hole :'()
So I dropped the caliper into near boiling water for 10 mins,let the alloy soak in some heat and expand.
Tried again -and out she came!