Hi guys,
I have a problem with surging/jerking my XT660Z r.v.09 53tkm.
Especially last 5 tkm is very strong (and I probably feel that it is increasing).
I've tried everything. Original state - added checked modified: new sprocket damper, new chain set, DNA stage 1 + 2, NGK iridium spark plug, KEV's fuel mod (try to sets from 3 to 9 clock) + O2 controller, blocked / unblocked AIS, deCAT exhaust. Checked fuel injector + fuel pump. Checked throttle body for leaking and everithing looks fine. TPS checked and set up according to the service manual (0,66V).
All of these modifications helped a little, but surging/jerking is still strong enough about 2500-3500 rpm.

When accelerating or braking, the bike runs normally. But in the city 50km/h 3-th gear it is enough to feel.

Engine disassembled 2 times.
1. 22tkm third gearwheel
2. 48tkm exchange drive axle bearing
could the problem be here? something wrong set / folded?

Please for any advice or idea where the problem might be.

W.