CBR 600F gearbox

The other day I started changing the trnasion kit of my Honda CBR 600F because it already touched him and also made a strange noise, and what was my corsa to verify that the noise came from inside the gearbox. When putting first (without transmission), the output axis hits as jumps, either in 1st or at any other speed. Save what can happen to you? I think I'm going to have to disassemble the engine with the gearbox, some advice?

Salu2 and thanks.