Overheated ZX - any ideas?

[ChristoT]

If you had a blockage or clogged up waterways then the coolant would've overheated, got pushed into the expansion tank then it would boil like a kettle and get dumped on the floor if it couldn't circulate properly.
Then when the bike cools down any remaining fluid would get sucked back into the main system, leaving you with a very low or empty expansion tank.

I've actually watched it do this on my previous bike.


That's why it's always worth the occasional quick shake of the bike on the centre stand to check the coolant level is where it should be, 'cos it's a very good indicator if the system's in good shape or not.
If all is well the levels should pretty much stay the same when the bike is cold, other than a very minor top up every few months if at all needed.

Oddly, the header level didn't budge an inch, and the full coolant level was present and accounted for.

If the water pump went poof though, the oil pump would have gone too. Oil starvation, and lack of cooling...  :'( :'( :'( This is beginning to sound pricey...