What causes high RPM misfire or sputter ?

its late and raining today so ill rebuilt tonight and tomarrow ill will video a Wide Open test and hopfully I cant catch a.good video of it cutting out. If the lead wire does fix it ill put the old one back in so yall can see what the bike was doing
I think I found the problem to my up top cut out. Anybody notice anything unusual? I must of been real dumb that day. lmao. This makes perfect since to the cutout and how it follows my rpm range going down
so this is my magnet position at top dead center. should it be more advanced or more retarded for high compression heavily ported motor?. yes the magnet is tacked in place. A bikeberry pull starter stripped the threads out.

reason i ask is beause im gonna change the magnet. it was raining today but managed to get one pull out of the bike and its still cutting out. but this time it wasnt until i hit 41mph. which is very high in the rpm range. say around 7500 to 8000. the base gasket was just adding to the cutout