Meaby I didnt explain myself corretly for the exhaust, infact I already got rid of the pre-cat and the cat, so actually my exhaust is a straight pipe ( + the raisonnator and the muffler).

Its COOL for your advice with the trace! what is wrong with the trace? I would be really greatfull to know how to analyse it, is it the burn voltage that is too low? Espasially on the primary ignition?

I'll check the coil resistance, to be sure that at least that is correct. For the plugs, they are new.

Any other advice with thoes trace? please?

Thanks alot guys!