02 700. Just under 3k

Topped the overflow bottle off after last ride, machine hasn’t been started since.

Go to use it today the bottle is dry.

No sign of coolant anywhere under machine.

Water pump seal or head gasket would present themselves with either weep hole leak and / or coolant smell vapor from the exhaust ; no ? Neither is present.

I did change the reservoir bottle bottle a few months ago as the nipple on the bottom hose had been cracked and was leaking. Air still in system ?

Just doesn’t make sense to me how it loses coolant while sitting?