Well, on my first SRX i had all sorts of problems with the regulator, and tried several different regulators (which may or may not have been
exactly the same, or known to be 100% serviceable

) in the end i bought a new one from Boyer/Brandsen, advertised in Classic Bike for Nortons Triumphs etc runs at about 90w i think, anyway....been on there for 9 years now. Cost about £45 i think