Hi All
I'm blowed if I can find this coolant top up tank.
Handbook says underneath the footrest left side. Another source said behind lower centre panel which you access by raising the seat then removing 2 clips then unhooking the lower centre panel... Nope, it ain't there either!
I can see where the readadiator cap is its behind a small access door in front of your knees when riding
Mines a 2019 model and wonder if there's been a design change?

It is at the bottom of the footboard on the LHS.
First remove the large panel between your feet by raising the seat and removing 2 bolts with Allen heads (I think), the heads will be upwards as you look down at the front of where seat would be. This also requires some fiddling with the seat to clear the lugs.
This will reveal the posidrive screw that then need to be removed to access the coolant expansion/top up bottle. It's about a 2 inch square panel in the floorboard. It's all how you access the battery as you will see for yourself.
Good luck, Hatter

You might find this link useful
https://www.manualslib.com/manual/73045 ... =46#manual