I have a cbr250r and it was stolen before I received it, so the ignition had damage on it. I bypassed the zener diode on the ignition by installing a power inverter and running a nine volt power supply to the wire on the ignition. And it ran like this for around two months roughly. I took it to the river and it has a pretty good strip to run the bike down. I was seeing where the top was with the new carburetor I installed bypassing the pump and injector style it had originally and running a gravity fed one instead as well as I had the rev limiter removed and new back sprocket and front sprocket. I hit around 135 roughly on the first run down then 142 second run turning around for the last time i got to a funny angle with the bike and just let it set down at walking speed i literally set it on the ground. I reset the ecu on it and tried everything from compression, carb, spark plug, ignition coils, igniter, checked the inverter, power supply, and everything else can't figure it out, but i start it fires up then dies 3 seconds in can rev it or idle for those 3 seconds but after that i have to switch off the bike with the kill switch and it will start again and then die 3 seconds in any help would be greatly appreciated. I am mechanically inclined but no master mechanic so feel free to lamen termed any of it you can lol thank you.