650 coil mystery please help

[Backyard Built]

i have a 1979 xs650 and whenever i turn the key to on the coil pulses spark to both plugs in a consistent rhythm like pattern like
ive checked fuses and ignition and searched for loose or broken wires so far no luck, any one run into the same problem

 

[jpdevol]

Howdy,

I've not experienced this phenomenon personally, but I believe it can occur if the engine cases do not have a good ground - continuity back to battery negative.

What ignition system is present (some do that normally).

 

[Backyard Built]

hey thanks for the info , i ended up buying a new battery and installing a voltage meter nd found out that my battery is being undercharged , my stator is olny putting out 12.5 volts so im going to take it apart and see what mite be causing the issue ,

 

[Jan_P]

hey thanks for the info , i ended up buying a new battery and installing a voltage meter nd found out that my battery is being undercharged , my stator is olny putting out 12.5 volts so im going to take it apart and see what mite be causing the issue ,

Often the Rotor . and please check the brushes