Clattering sound cbr929 - solved
I think I've solved it.
I filled the cooling system and started the bike. Clattering like a very clattery thing.
As the bike got up to temperature it didn't sound quite as bad. Got my long screwdriver out, placed one end on the cylinder head and the other end to my ear - nothing that sounded too bad. Did this at different places along the head - no clattering. Swapped positions down to the cylinder bases - again nothing too bad.
Throughout all this the engine was really responsive and revved freely. So started listening to the exhaust valve with the screwdriver. Nothing wrong.
Moved the screwdriver up to the water pump. What a bloody racket!!!!!!!
Like a little hammer banging away. When I removed the water pump (it's a good idea to drain the oil so you dont lose it on the floor like I did)
I discovered that one of the retaining screws had taken a knock and had damaged the water pump housing causing cracks but not enough to leak. I can only assume that this distorted the casing enough to cause the clearance of the impellor to be reduced leading to the bloody awful racket.
Anyway, when I replace it I'll let you know how quiet it is.
Thanks for all your ideas.