Z1000 A1 whats causing this

[S240man]

I need a bit of help please. Just put a 77 Z1000 back on the road 500 miles back after a restoration done by previous owner . Been running great until yesterday. was out for run with friends 60 miles into journey stopped for cuppa and on start up it fired ran then stopped, just thought it was my poor start technique. Tried again but start button just dead but ignition showing on and in neutral. checked kill switch ok, no joy tried kick start, no joy. left it couple mins and started ok and thinking , what was that about, no power via start button ? so a bit concerned in back of my mind. 10 miles on rough running loss of power starts to show , thinking ignition (on std points not electronic ) or fuel but getting worse. got pulled into service station , just before switching off , tried to see if increase revs any signs of headlight getting brighter but could not see any increase and the bike not sounding great sure not running on all cylinders. Not too much that I could do at roadside and did start to think this felt like previous problem on another bike that was loss of battery power/ charge. Trusty breakdown service AA called and attended. I suggested poss generator /regulator/rectifier issue . quick check revealed 17/18 volts going at battery with minor drop when lights put on but no sign any light bulbs blown but way more than 14.5 V or so that would have expected. So Ok have a problem with charging system over charging ? but what is the rough running and why ? not a flat battery but what fails with over charge ??? . Was not too far from home but reluctant to try ride home in case sudden cut out but decide to try this with AA vehicle behind for safety etc. 10 mile limp home struggling to get 50/60mph clearly some cylinders are not playing ball . got home and find 1 and 4 ex pipes are hot 2 and 3 almost cold . I am thinking this is purely electrical issue, I guessed the coil that serves 2 and 3 cyl has failed but why would over charge cause this and what was the initial fail to start issue before the rough running. I am wondering was fault developing before that 60 mile stop for cuppa and battery Voltage/capacity was getting critically low but as batteries do, it built up enough after been stopped 30 mins enough for one start which it managed but then cut out. was I then faced with not enough volts to restart but again waiting few mins battery built up just enough for the start that got me going again. Did the generator /regulator then go from under charge to over charging and cause damage problems with coil for Cyl 2 and 3 ?? Only things certain of is big loss of power cyl 2 and 3 not working( not checked for spark yet ) and would not expect to be seeing 18V at battery when engine running. New battery was fitted at restoration but no evidence of new generator,rectifier/regulator Any thoughts . likely explanations and course of actions really appreciated. I will get there but using the group experience be a whole lot quicker. Many thanks Martin

[Ultim8pc]

Sounds like your reg/rec has failed.
You need to check the stator output across the three yellow wires (1&2, 2&3, 1&3) and I think you should be seeing 40 to 50VAC. If the voltage rises as revs rise then you have a stator issue and it'll have to be replaced. Then replace reg/rec and ensure the battery voltage is OK when not running and that the reg/rec is working as expected. (13.8 - 14vdc maximum output at 4k RMP and above).

[KeithZ1R]

Whole world of stuff going on there but in a nutshell , voltage regulation has failed and in the proccess has probably damaged the battery and definitely taken one coil out, a combined reg/rec is the first thing to replace and at least one new coil , see how you get on with the battery if its a sealed unit showing any sign of puffing ,bin it if not then new electrolite may rescue it...good luck, oh and as an aside you will not be the first that has had this problem this month you havent mentioned if you have the original voltage control system in place or a new combined unit, either way its a replace sutuiation.

[S240man]

Thanks to the replies above, all helps know on the right track . I will be changing stator, rectifier, regulator, both coils and the battery regardless . will do relevant checks and keep anything that seems ok but as spares . I am thinking if one coil has been cooked due to the over volt then the current working one probably has at the least been baked or had a hard time of it. I am prob lucky the battery has not fried and shed its acid across back of the bike , now that would have made me cry. On a bonus I have a baby sister to the Z1000 in the way of a 77 Z650 , the 650 does not get as much use at it should but hard to when the bigger lady looks so good. I will be getting the z650 dusted off not ran for 4/5 weeks , give me a few days to sort out the 1000. Again thanks for the thoughts and advice. Martin M