Step by step TM - you’re a smart guy and you can do it!
Obstreperous does not equal dumb!
Obstreperous does not equal dumb!
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Stock 78e low charging behavior
- Thread starter TimeMachine
- Start date
TimeMachine
SeventyEighte
Thank you everybody, I took a chance and gave it a shot today. It is clear that the rectifier is quite suspect. DB I believe you . It is clear that improperly mounting the brushes results in an apparent dead charging system. Mounted correctly there is noticable life. It is clear that some old corroded connectors are also suspect. That main one between the air boxes I didn't get apart today. On the positive ! As you all have known me as a member, recent life changes have better enabled me to attempt this fix and I have the VR115, the rectifier, and now brushes too to aquire for the next attempt. The XS is secure in a nice garage below me waiting now instead of a rotting lawn mower shed. I did enjoy a short ride again in the neighborhood. The XS sits nice. It will be very nice when I get through this. Realize, I have ridden my BMW f650 all summer and now fall even and it has been quite a blast but, The XS feels naked , low, and vintage ! XS gearing is a little taller and that twin feels like it wants to GO ! The disppointment of todays failure is subsiding as Optimism is prevailing ! Thx again -RT
While watching running charging voltage, jumper a lead direct from the battery (+) to the outer brush. This bypasses the regulator, and should induce max charging.
If voltages come up, suspect the regulator and/or the brown wire feed to it.
If not, suspect the rotor and/or rectifier.
If your jump lead gets hot and smokes, that confirms the rotor is shorted...
Lack of charging has been solved on hundreds and hundreds of threads on this site. The first step is to check that brushes are long enough (3/8" is minimum). While they are removed, you measure the resistance between the 2 slip rings (should be approx 5 ohms). Also measure from either slip ring to the rotor frame (should be very high resistance).
The next step is to do what 2M just posted above, the regulator bypass test for the 1970 to 1979 years. With the jumper wire in place, rev up the engine and battery voltage should go up to +14 volts.
Don't even waste time measuring the old stock rectifier, toss it into the garbage. Buy a new 25 amp, 3 phase rectifier from Wind Nation or is it Windy Nation? Same thing for the stock regulator. Yes it may still work, but they don't work well. Buy that VR-115, and it will charge your battery at 14 to 14.2 volts.
The next step is to do what 2M just posted above, the regulator bypass test for the 1970 to 1979 years. With the jumper wire in place, rev up the engine and battery voltage should go up to +14 volts.
Don't even waste time measuring the old stock rectifier, toss it into the garbage. Buy a new 25 amp, 3 phase rectifier from Wind Nation or is it Windy Nation? Same thing for the stock regulator. Yes it may still work, but they don't work well. Buy that VR-115, and it will charge your battery at 14 to 14.2 volts.
Last edited:
TimeMachine
SeventyEighte
I hear you too RGman , Nice to have the advice and concern here on XS650.com ! Hang in there with me everybody. As I really would prefer to be posting ride pics 
Bobbert
XS650 New Member
I’m new to the Z’s 650’s . I’ve built cb750’s and was wondering if anyone has the wiring diagrams for the windynation rectifier and the vr115 regulator. Thanks!
