Could be the rings bedding in properly, and of course the oil has an effect too. You'll get better figures hot aswell since it's all expanded - and that's how it'll be when running.
If head gaskets are easier to get, take the head off instead!
No chance of getting the servo motor fixed then?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball