Radiator confusion ST1100

[ST1100Y]

I assumed the ST1100 would be the same as the 1300 in this respect.

ST1100 has one radiator, transverse; inlet: right top, outlet: left bottom...
Orientating the inlet up (leaning left on side-stand) seems to burb any trapped air out the rad into the t/stat housing more efficiently while refilling an empty system...

 

[Road Slug]

I refilled the coolant after draining, filled up, ran bike on centerstand until the temp got off the cold mark, shut off bike and let cool down enough to remove cap the topped off.
Took an additional half pint.

 

[Zider drinker]

... and if the overflow line is cracked hence leaking air into the system, you'll end up with a solid looking level in the reservoir, but an already half empty cooling system, blowing your head gaskets while at it ...

If it doubts you need to check proper levels via the rad-cap...
I'd managed to do that (and refill) by reaching up aside the RH fork tube, undoing the cab, topping up by using a small funnel with a piece of hose attached...
With bike on side-stand (ensures thermostat housing being the highest point, hence vent all tapped air), start the engine and let it idle (do not blip the throttle!) while observing the level in the filler neck, top off when required, but once the liquid movement inside gets stronger (=> thermostat opens), kill engine and place cap back on; remember to twist it over both notches to close fully.

I like this method will try it and thanks