Give us as much info as you have to hand...

Flat battery? Battery voltage?

Bad earth to ECU?

Does everything else work normally, headlights bright, etc?

Sounds like a more general power issue rather than engine specific from the limited info provided.

Try replacing all of your earth cables and cleaning contacts, or use jumper leads for "proof of concept" testing between the battery, chassis, body and engine. Everyone tends to concentrate on getting "good 12V" happening and forgetting that it's a return circuit via earth.

2002 Sporty , Ironman 2.5" spring, 2" body, 15 x 7 ROH wheels, K&N, 15 x 10.5 Simex Centipedes, Powerchip 91.

"Never argue with an idiot. They will bring you down to their level then beat you with experience!"