Reply To: Upgraded regulator rectifier and stator
It sounds like your harness may be the one that’s shorting somewhere along the cable or a part is frayed bad causing it to cause instant shorts.
You will have to end up going through a painful process of stripping the harness down , checking every wire and then rew-wrapping the harness after you find or fix any faults you may discover. We don’t know if other parts on the bike are fried ?
Sounds like the fuse is doing its job bursting before it cooks anything attached to the harness ie. dashboard , coils, engine black box, speed sensor etc, they use 12v as soon as key turns on.
The engine black box is the most difficult to replace, so leave it disconnected. Even the starter motor relay has permanent 12v even if your keys are OFF, only the CDI + right switch handle triggers it to go and spin the starter motor , the 12V signal to the regulator is always live even if bike is OFF, regulator won’t do anything until the stator sends AC power to it and then it converts it to DC to charge the battery. Retrograding from the harness itself is rare but happens.