Greedies on Filton Avenue in Bristol.
Hungry Horace (NOT Horse) on Speedwell Road, Bristol.
Both of these places do the biggest builders breakfasts you can imagine. chips, sausages, bacon, 2 eggs, beans, mushrooms, waffles, tomatoes, fried bread and toast plus tea with as many top-ups as you like.
Its not gourmet organic food but it is mountainous. Its the kind of thing you can only justify once a year or so due to the artery clogging properties of it.
However my favourite greasy spoons of all is my house! We get eggs, sausages and bacon from Model Farm in Ross On Wye and the missus cooks up a storm in the kitchen.
She has a GS650 and myself a GS1150A so we will have to get some fellow tossers round to join us some time!
Brunel Buttery on the Bristol docks is also good.
Also if you get off the M4 at the Bath junction but go the opposite direction to Bath (heading towards Stroud) right there on the left in the parking area is a guy who does good fry ups. However its always a gamble as to whether he is there - its usually just the mornings.