Dyna upgrade z1a

Going to upgrade to a dyna ignition will stock coils work  or should I  change them out

The reproduction stock coils will work as they are 4 ohms.
The Dyna coils that they would recommend for your swap are 3 ohms

I know that doesn't really answer your question 

If the stock coils resistance is within spec then there is no reason to change them

Coils for Dyna 'S' should be between 3 and 5 ohms ( 5 for road use and 3 for race but most people just fit 3 ohms) so stock Kaw are fine.
However using matching Dyna coils will get the best out of the system as they produce a much stronger spark ( 35000 volts ) compared to stock which results in a fuller burn and more power especially at higher rpms.

 

Bike is a 74 z1a with low miles just want to change out the old style ignition  probably ride less than 1000 miles a year thanks for the quick response 

z-fever.de/shop/en/product_info.php?info...nic-z1-900-1000.html

z-fever.de/shop/en/product_info.php?info...1006--advancer-.html

If the ignition is on and motor is not rotating the ignition coils are switched off.
This overloading the ignition coils and accidental discharge of the battery can be prevented.
No Blackbox original appearance is maintained.
Adjustable without strobo light.

 

 

Your stock coils will work but if you want to change to a complete Dyna system you will need the green coils and a Dyna DS2-1 ignition.

www.dynaonline.com/parts/kawasaki/kz900-z1/1974