timing advancer Z1A

I have a 74 Z1A and am having trouble setting the timing, although at idle timing is spot on as soon as you rev the engine the timing becomes very erratic. Does that mean I need a new advancer or could it be something else ? The bike has new coils plugs leads electronic ignition. .Any help would be much appreciated. Thanks

Common problem with all older units. It's the advance weight springs. Instead of holding the advance weights, worn springs just slap and bounce around. I am assuming your using an old style car timing light? And at 2500-3000 RPM's, the light just goes all over the place. And as of yet, no one makes them aftermarket. Some guys try and squeeze em closed, some guys cut a small amount off and re-bend. But that stuff is high tensile carbon steel. Might get lucky and find some at an older established Kawasaki Dealership.
DON'T buy used ones from ebay! Unless it is NOS.
Early Z1's advance curve was different 40 degree 3,000rpm's, then, Z1A vin #32800 and later, full advance@ 40 deg. BTDC came in around 2,300 rpm's Or something like that. Old dragracers welded the stock advance units fully advanced.
So, it's a little harder to find a certain spring, trial and testing?
There might be some out nowadays, remakes? With all the retro, restoration from Japan, (Doremi) (PMI), Z1-Parts in California and whomever?
Contact Jeff Saunders at Z1enterprises, If anyone would know, them Guys will!
I sure would like to find an old dusty bag of 100 NOS Z1 springs from an old closed up dealer.
They would be like gold on ebay!

Good Luck!