Suppression core plug wires are known to have a more frequent failure rate and a shorter life-span than do solid wire core plug wires.
Could consider tossing the existing "old"
resistance plug wires, and install new solid copper core plug wires.
www.z1enterprises.com/catalogsearch/result/?cat=&q=plug+wires
The copper core Dyna spark plug wires are
non-resistant with a non-resistor cap.
The advantage of
new plug wires is not having to worry about leakage of high tension voltage through old hard cracked insulation often present with old plug wires..
Factory KZ's came with solid core plug wires and non-R (i.e., non-resistance spark plugs such as NGKB8ES), together with a resistor cap.
One and only one resistance component may be used in the secondary loop (i.e., cap OR wire OR plug).
More than one resistor component is too much resistance, which weakens spark.
Actually don't need any resistance component in the secondary loop, which many owners achieve by fitting
non-resistor caps to the stock wires and keeping the same stock
non-R plugs.
Running without a resistance component in the secondary loop is expected to cause radio interference (if that matters).
Good Fortune!