Did recent 3 day race training school on recently purchased NC29 race bike.
Battery was unexpectedly flat last time out but would start on the button with a boost.

On looking, 3 wires going into rectifier had melted. Any idea what caused this?

Rectifier is fubar. replace it with a 5SL R6 one

if its a race bike, get rid of all that and build yourself a simple loom that just has the essentials...

Col