I still disagree.I've just checked my coolant level in the Rad and it was low so no coolant has been drawn back in.
Car cooling systems have two radiators and are sealed from the atmosphere including the Expansion bottle.
My 1999 curvy and previous Hondas use the same,"Open to the Atmosphere" expansion bottles.
I've also checked the Partfiche for the 2017 SVs and the expansion bottle is also open to Atmospheric pressure TTBOMK.
There's plenty of images for how a Car cooling system works differently from Motorcycles,
https://www.google.co.uk/search?q=ca...w=1440&bih=763
I'm not going to argue the point any more just agree to disagree but I would urge anyone reading this to check the coolant level in the Radiator on their machine with the Engine cold and don't trust the Expansion bottle level.Only takes a minute.Just remember the little screw that locks the cap( there's one on my Curvy).