Power Way down after Bike Repair

I am at level 45 so not new to Zwift, I have a Tacx genius 2040 (auto calibrating?) I used to be able to ride at 1.8-2.0 watt/Kg and easisly hole 32kph on the flat. Since a repair to the bike (deraillier cable) I am now struggling to hold 1.0-1.2 watt/Kg and around 23kph on the flat. I don’t believe I have suddenly got this unfit!! As the 2040 genius is self calibrating I can’t go this route. Anybody have any ideas as to what is wrong??

Probably to do with the way the bike is mounted on the trainer. Check the manufacturer instructions for tyre pressure and how exactly to tension the roller against the tyre. Wheel-on trainers are very sensitive to how they’re set up.

Thanks for your advice Steve, I have tried remounting the bike a couple of times and checked tyre pressure and roller tension. Unfortunately, no joy as yet, but I’ll keep trying!! I appreciate your input. Thanks