stewart-250

A bad ground will stop things working but will not blow fuses. Live things connecting to ground when they shouldn't is what blows fuses.

Could very well be something bad happening inside the ignition switch as was already pointed out as both the main power and the pilot light circuits pass through there.

But as you point out it seems to happen whe the steering lock is put on so it could be the harness at the headstock.

I would try to get the fault to happen with the bars on full right lock then on full left lock to try to pinpoint it a bit better.

Sorry can't be of more help but am stuck at work without a workshop manual or time to look up an online one.

cheers

Stewart