Change the coolant every year to be sure, else it will stop protecting against corrosion & you don’t want that, it kills cooing ability & can damage parts.
When you change it flush the system out with a hose backwards & forwards to try to clear crud from rad etc.
You may find your head gasket is leaking a bit when real hot which either the water is ingested into the engine or blows out into the overflow bottle, depending on it’s whim, but usually out. If it was sucking back in (ie: when you stop it & it cools perhaps) then the overflow would go down. Or the other theories about shake.
But the head stay apparently pulls on the head when the frame flexes & can cause problems. Check this isn’t a huge source of tension & drill the mounting hole in the plates slightly bigger to be sure.
Also check the gear oil isn’t contaminated which may indicate a worn w/p seal.
My 91 KDX played all these games but seems to use fairly little water now.