Plastic reservoir with a cap behind rear shock (2001 Fazer 600)

[vladman]

Everyone, again, thanks very much for the detailed replies.  I know the coolant was changed and the system flushed (at my request, as I had no idea when it was done prior to that) about 2 or so years ago.  Changing coolant is one of the few things I've never attempted to do myself on my bikes, I think I got scared away from doing it when I read something about air getting into the system and being a pain to get out.

I'll have another good look at the level, and then take it from there.

Thanks again.