I did 632kl in mine before I put 56.4L in it the other day (shitting myself lol) after a trip down south but around town my fuel light comes on at around 470kl with 9 litres left in the tank.
Did you put the 60L tank in or did you leave the 50L in it?

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Beaten up old 98 Gen 2 Liberty, 13.0, stock V3 STI running gear.
07 Transit motor home
69 VF & 70 VG Valiants needing full restoration
Yamaha Zooma 50cc rocket hopefully going with the Transit.