When i apply my rear brake hard it jumps ?

[ko5i]

Hi all,
Recently i realized when i applied my rear brake harder the wheel locked up but it felt not really smooth ?
Felt like the brake caliper was hitting the frame/stopper thats on the swing arm all the time while i was braking [knocking noises] and also felt that too.
I checked the brake caliper and it doesnt really move that much but it moves slightly off the rotor and back i would say 3/4 mm up and down but all the screws are tight so i don't know whats wrong

Thanks for help !

[stinkwheel]

I presume you're braking with the front brake at the same time?

As such, the bike will be diving forwards, unloading the rear. If you then lock the rear brake but have the bike still in gear, the engine is still trying to turn the wheel and will instead try to lift the rear wheel off the road, loading the suspension up again*. This alternate loading and unloading of the rear suspension makes the back end "chatter".

More front, less rear.

* If you hold the rear brake on hard and try to ride away from a standstill, you'll feel this effect make the bike squat down.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[ko5i]

Oh yeah makes sense now, as i was bedding my rear pads so i was only using the rear brake mostly i pulled clutch but when i didn't that happened so yeah now makes sense thanks !