The stock NGK ignition wires from Triumph use EPDM rubber as an insulator over tinned copper wires and the NGK SDO5F plug caps. EPDM is prone to dielectric breakdown and moisture penetration after a couple years. The NGK plug caps are not sealed properly where the wire lead enters the cap. Brent's NGK wires are sealed with silicon and then the rubber boot placed over the cap. Brent's NGK wires also use silicon coated wire instead of EPDM. In my estimation the stock Triumph wires life span is probably 2 to 3 years years at best.
