Without a dyno, all you can do is go by feel and spark plug colour.

A nice tan and all's well in the world. White and it's on the verge of going bang, black and it's safe, but too rich and not giving you all the power it can.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball