Z1 Classic coil secondary wire replacememt

Question. Are the spark plug wires removable from the coil body on the z1 classic coil? I don’t want to ruin them trying to twist them out.

 

I assume you mean the ones with the ht lead moulded into the coil body?
If so you can slide a thin electrical screwdriver or thin blade or the like down between the lead and the body to release the glue all the way around. At the bottom of the recess is a straight prong that makes contact to the copper ht core. It's not threaded so straight pull off. 
When fitting a new ht you'll need to glue them back in and seal the joint with silicon. You don't want damp getting in there. 

Ok thank you.  I did manage to pull it out but unfortunately the cable stayed secured and the covering came off.  The cable looked like it was soldered at the end.  .   I managed to get the covering back on and put a splice joint right at the exit of the coil. Seems to be working ok.