overcharging

hi guys. i have a '77 kz 900 that overcharges. new battery[interstate], replaced the regulator and the rsctifier with z1 enterprises updated plug in unit. charges ok when at idle and low revs. higher revs it goes well past 15 volts. i always shut ut down before it gets to high. bought this bike 8 months ago.wouldnt hardly run at all, and figured out someone had the cams in backward.figured the tach gear shouldnt be on the back cam. reinstalled the cams, set the valves, and it runs great! now if i could just get this electrical problem figured out, i could ride this thing.
thanks in advance for any ideas. bruce

Will assume new regulator is okay. But maybe a faulty wiring connection is preventing it from properly functioning.

If not already done, would assure a good solid ground connection where the negative battery terminal attaches to the engine or frame. Most of the bike's electrical components do rely on grounding to the frame for return to the negative battery terminal. Would also double-check all the wiring connectors for a good clean snug fit, and for any blown or loose fuses. And of course assure clean tight connections at both battery terminals. Good Luck!

thanks for the imput. i'll check what you suggested, and get back to you.

traced it down to the brown wire on the horn was grounded. then, traced that to the oil pressue switch. unplugged that, and the ground went away. now, have no headlamp. i first noticed it only overcharged with the headlamp on. off it was fine. i'm thinking its in the dash. the nutral lamp doesnt work, and am not sure sbout the high beam indicator.
i'm deturmend to find the problem, but not there yet.

The brown wire on the horn is the HOT wire to the horn. When you push the horn button, the ground connection completes and the horn sounds. The wire that goes from the horn to the button is black. The regulator/rectifier is responsible for making the AC waveform into a DC and then making the waveform into the correct amplitude. You are having problems with the amplitude. The amplitude is set based on feedback from the bike's wiring. What color wires come off your reg/rec? I suggest they will likely be the three yellow for the stator, a black for ground and a red for the hot wire. The hot wire on the more modern reg/rec units not only goes to the main fuse and battery but provides the feedback for the regulator function which controls amplitude of the DC waveform. This is where you problem is... not in the horn, neutral indicator or elsewhere. If the reg/rec is hooked up correctly then it is defective. Talk to the folks at Z1Enterprises if it is as I suspect they can help make the situation right. I am not sure how you would test the reg/rec off the bike or electrically... you might go to the manufacturer (Ricks?) and see what they say. You must have received their address or contact info with the unit.

hi guys. thanks for the advise.finally got the 900 acting like it should. either it was the aftermarket ignition switch [ which it could have been off a later model] or the wrong dash wiring. which was probobly off the same parts bike they used. they had it soldered in to the factory plug in.
what i did was, i found the correct wiring off a 750? or a 400 that i parted out a few years back. took the wiring and adapted it to my dash. swaped out ingition switch, and wala! everythig works as it should. now i can ride. thanks for the help. bruce