The radiator MUST run to an expansion bottle, but that can be a small drinks bottle rather than the bulky proper one. It needs to be easily accessable so you can drain it when it gets full.

Remove the rear pillion pegs, and if you are keeping it on the track, saw off the subframe behind the front seat.

You can junk the oil pump and go premix for more weight saving / simplicity.

Strip the wiring loom to race electrics only - I saved a whole KG doing this on an FZR400.

Go on a diet! Most blokes I know would rather hack bits off their bike than loose the extra two stone they're carrying...
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball