Peugeot Jetforce 125ccm Electrical Problem

Good day, I recently bought a Peugeot jetforce 125ccm in a rather bad condition and wanted to rebuild it over my holiday and then drive it myself. The engine ran perfectly and I also drove without rear brake, because the caliper was not fixed. When buying was like in the attached picture this guide for the brake caliper broken off. Since my father can weld this was at first no problem, however, we told it beforehand that After welding with 110A I fixed the brake and finished everything. When I wanted to start driving the indicator light started to flash and the speed went up to 3000 revolutions and stayed there. I could not give gas either because it only turned up to 3500 and started with false ignitions. I already checked the fuse under the Sozius as well as all cables under the helmet compartment. After the error reading with the engine codes was only the error : 2 I don’t know any more and ask if anyone could help me with this.