Just for my own knowledge i searched for some keyboard weights...

Roland E80 22,5 kg
Roland G70 20,5 kg
Korg PA2X 18 kg
Wersi Abacus KS1 18 kg
Ketron SD5 17 kg
Yamaha Tyros 2 15,5 kg
Korg PA 800 13,3 kg
Roland E60 13 kg
Yamaha PSR S900 11,5 kg

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Some extra info on synths and stage piano's to compare :

Roland Phantom G8 32 kg
Roland Phantom G7 16,5 kg
Roland Phantom G6 14,5 kg
Roland Phantom X7 14,5 kg
Korg Oasys 76 25.7 kg
Korg Oasys 88 32.1 kg
Yamaha Motif XS 7 17 kg
Yamaha Motif XS 6 28,6 kg
Yamaha S90ES 22 kg

Roland RD700GX 25,6 kg
Kawai MP 8 II 35 kg
Yamaha CP300 32,5 kg

Roland V-synth GT 13.8 kg
Korg Radias 8.7 kg

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Its obvious that ROland can build lighter 76 key arrangers that are very stable, just have a look at phantom G7 thats only 1 kg heavier then Yamaha T2

I think the Korg PA2X is at a nice weight for a sturdy 76 key arranger. While the Roland E80 is a bit to heavy for a 61 key arranger.