u/Anymousy

I have a situation with a 2011. Year - model: S1000RR. I bought the bike 2 years ago and it never had any problems. Last autumn, I installed a completely new chain kit with everything that normally gets replaced at the same time. After that, I rode it and everything was fine.
This spring I went for 2 rides, also with no problems. Then the battery died, so I replaced the battery — and that’s when the problems started.
Now the bike no longer runs properly. It feels like one cylinder randomly stops working from time to time, and the bike loses power.
I replaced all 4 ignition coils with brand new original BMW ones.
When connecting a diagnostic tool, it shows that the exhaust gas valves are not working properly and that one sensor/lambda probe is missing. However, all mechanics say that neither the sensor nor the valves are causing the issue. The bike always ran perfectly before, with no modifications. It was already bought with a FULL AKRAPOVIC exhaust installed.
Fuel pressure from the pump is perfect, and the spark plugs are good.
Any ideas on what to do or what to check next?
At the moment, I’ve taken it to another mechanic who prepares motorcycles for racers. He’s already spent 3 days on it and still has no idea what happened to the bike.

I have a situation with a 2011 S1000RR. I bought the bike 2 years ago and it never had any problems. Last autumn, I installed a completely new chain kit with everything that normally gets replaced at the same time. After that, I rode it and everything was fine.
This spring I went for 2 rides, also with no problems. Then the battery died, so I replaced the battery — and that’s when the problems started.
Now the bike no longer runs properly. It feels like one cylinder randomly stops working from time to time, and the bike loses power.
I replaced all 4 ignition coils with brand new original BMW ones.
When connecting a diagnostic tool, it shows that the exhaust gas valves are not working properly and that one sensor/lambda probe is missing. However, all mechanics say that neither the sensor nor the valves are causing the issue. The bike always ran perfectly before, with no modifications. It was already bought with a FULL AKRAPOVIC exhaust installed.
Fuel pressure from the pump is perfect, and the spark plugs are good.
Any ideas on what to do or what to check next?
At the moment, I’ve taken it to another mechanic who prepares motorcycles for racers. He’s already spent 3 days on it and still has no idea what happened to the bike.