TOPIC:

I'm getting the dreaded overcharge. Mid 13s at tickover, 15.2 ish at 4000 rpm. Not real bad but still high. I've done most of the checks on here, here's the wierd thing. Checking the voltage across the fuses I get the same voltage as the battery at both ends of all the fuses except 2. The top 2 in the picture..meter goes crazy on the top one and reads almost nothing on the next one down. With engine running the bottom 3 read just over 1 volt, the top 2 read as they did with the engine off !!! Fuses are all checked good. Help, confused.

When you measure voltage drop across a fuse it's no different than measuring voltage across a piece of wire a couple of inches long. You should get virtually no reading at all. If you do it means you have some resistance across the fuses, probably due to corroded contacts, and you should clean the contacts and re-install the fuses.

When you measure voltage at the battery you are measuring the voltage drop between the start of the circuit and the ground post. At this point you should have the full voltage potential of the battery.

In addition to hardrockminer's advice, please consider this; the early OEM fuse on Z1's had the fusible link attached to the end caps with solder. Age, heat & vibration can make the solder joint on the end caps crack, leading to maddening intermittent problems.
We don't know when Mama Kaw started using fuses constructed without solder. Your bike is clearly more recent.
May we suggest examining the end caps of the fuses, looking for solder blobs. If seen, replace with more recent fuses that are constructed without solder.
It's also worth examining any pin connectors related to the charging circuit for corrosion or hear damage. Resistance across the ignition switch re: charging circuit might be an issue too.

Good Ridin'
slmjim & Z1BEBE

What slmjim+Z1BEBE said is exactly what happened to me. The fuses looked fine, but a filament was detached at the cap - not blown, just detached. I replaced all the fuses and had no more problems. Ed

Thanks for your replies guys. I've ordered a set of new fuses so will change them when I get them. I'll admit now that I know nothing about electrics, but hey, restoring this old girl is a lot of fun and learning as I go. All the connectors and wires appear in excellent condition, I've cleaned all the earths too. I appreciate all of your help, please keep any advice on testing as simple as possible for a novice like me.....

I took a chance and changed the rectifier/ regulator even though the old one was testing good. Am pleased to say that now the bike shows 13.9 volts on tickover and never goes above 14.3 volts at any revs..
Strange though considering the old one tested good !!