would Oil in airbox and some oil on air filter cause bike to stall?

it's a Carb Bike (02 Suz SV650) and the power is lost intermittently around 70 mph until the intervals become to quick and the power is lost until stall. There was like half cup of oil in the airbox prolly due to a drop .the breather filter(sponge) drained the oiled or it came due to putting too much oil. any ideas?

Sounds like your crank case is becoming pressurized.

replace spark plug ya probably fowled it