Pulsing when using front brake

I've had this issue for as long as I have had the bike but can't seem to find what's causing it.

Basically when heard braking at speed the bike will shudder slightly and when using the front at slow speed the bike almost pulsates similar to you constantly squeezing the brake, letting off, then squeezing it again. However you can't feel any of this through the lever.

So far I've had new tyre, new brake discs, new pads and calipers and new head race bearings but the problem still persists. Wheel has been checked by a garage and it isn't buckled. Only thing left is new wheel bearings which I have, I just need to fit them.

Any other ideas as to what can cause this?

[DJ123]

Are the discs mounted to the wheel correctly? Not too tight or too loose, no missing bushes etc?
Are the callipers fitted correctly & working as well as they should?

I'll check the discs again when I have the wheel off. Just seems odd that I've had the same problem despite replacing everything bar the rim and bearings.

[DJ123]

Do you have linked brakes? Have you checked the rear brake set up?

Linked brakes? If you mean both front and rear from the same lever then no.

[DJ123]

Originally Posted by Dunn-y

Linked brakes? If you mean both front and rear from the same lever then no.

ABS?

Nope. I've got a 2000 model ZX9R

[DJ123]

Check the disc bobbins on both of them. Make sure they are free and move. They can cause the disc to go out of line

Biggest cause of this is warped discs, sticking bobbins can cause issue too.
Too harder a pad can cause some glazing of the pads which I've heard people have issue with but I've personally not had it.

I had warped discs suddenly appear on my sprint, I'm convinced it was uneven cooling, I used to hold front brake on when stopped, so when I was in Normandy, wife was pillion, it was p*ssing it down so when stopped the rain cooled the part of the disc that was exposed, the pads maintained the heat on that section.

I would bet it's your discs tbh.

They all seem pretty free to me and even if they weren't it doesn't explain why I still had this problem after fitting brand new discs. I'm completely stumped to what's causing it.

Also there is no pulsing through the lever at all. It literally just feels like you are constantly re-applying the brakes.