My bike was backfiring on deceleration way too much and with the 4-2-4 nasty boys installed was worse and louder, after reading the simple instructions of this website plugged the AIS and voila what a difference !!!!!!!!!! I still have some but improved about 80%
I will need to synchronize my carburetors but before I buy anything I will try to see how is done
just want to say thanks to the group the info here is priceless !