My brother owns a 1982 XJ750 Maxim and we have replaced the TCI, relays, the two coils just to find out that the coils are not receiving current to produce sparks for the plugs. Everything has been checked for continuity showing resistance. We discovered the diode wire melted and put a 30A fuse and the bike won´t start. The last thing to check will be the engine switch. We are considering get a different wire harness. Need anyone´s input. Thanks.