Toilet Noise

[Bing]

I Folks.

I have had a noise problem in my Bathroom for a long time now and feel its time to ask for help.
It sounds like the Pipes are Banging and it can happen at any time Day or Night, even when nobody's in the Bathroom. I have come to the conclusion that its something to do with the filling mechanism of the Cistern. I changed the old Ballcock mechanism for a new styled White Plastic Float type with a small Diaphragm inside and thinking back it probably ties in with that exchange when the problem started.
If I remove the Cistern Lid and old the Float down to allow more Water into the Cistern and then let go, I can simulate the Noise as the Float shuts off the Water. It sounds like it is Slamming Shut quite aggressively. I can't seem to adjust the Float so that I get a smooth shut off without this Slamming happening. I also can't understand why it is Slamming during the Night when no ones up. I am wondering if it Could have something to do with atmospheric Pressure causing the Diaphragm to come off its Seat? I might hear this 10 times during the Night and sometimes only seconds apart.
If any one has a solution I would be very grateful to hear from you.

Best regards.

bing.

 

[denso13]

Do you have a valve on the pipe feeding the cistern? If so turn the water flow down and see what happens.

 

[HERTS P&D]

Fit a new float valve to the toilet cistern and cold water tank (if you have one)

Andy

 

[Charnwood]

Modern inlet valves (part 4 equilibrium) tend to have a more positive stop as opposed to the gradual closing with an older part 1, part 2 or part 3 valve.

 

[Bing]

Sorry for the delay Folks, I had to go out.
Firstly let me offer an apology for duplicating my message. I couldn't see it the first time.
denso13 I have looked and yes there is a Flow Valve for the Cistern. I have choked it back 1/4 turn an Hour ago and will now monitor. So far so good, no random noises. I will keep you informed if it persists.
I have thought about swapping the Float, but because it operates just fine, I presumed I hadn't set something up correctly and that's why i am fishing for help.
Thanks everyone.

Best regards.

bing.

 

[polesapart]

Fit a Fluidmaster "ballcock"

 

[Bing]

denso13.
It's been 3 Days now since choking back the Valve and everything seems fine, no strange banging noises. How simple was that!
Thank you for helping & thanks also to everybody else who replied.

Bing.