Z1000 poor charging

[Freebird]

Hi All

This is my first post having recently bought a rather lovely Z1000A2 of 1978 vintage.

I checked the charge to the battery as part of my familiarisation process rather than actually having an issue and found it's not charging as well as it should.

I have 12.3v across the battery with the engine off, this drops to 11.9v at idle and won't go above 12.7v when revving to 4-5k.

I checked the output from the alternator and was getting over 50vac when revving it hard, lower at lower engine speeds. I thought that was OK, so I replaced the new looking 5 wire reg/rectifier is had on it with a new 6 wire one from Z-Power. Unfortunately that did not make any difference.

The only test that is a tad dodgy is the resistance across the 3 alternator wires. The Clymer manual says 0.5 - 0.7 Ohms, but mine are around 1.1 Ohms.

It that bad enough to cause my problem? What else can I try?

Cheers

Glen

[Garry.L]

viewtopic.php?f=4&t=45636&p=379113&hilit=z1000+charging#p379113

[Freebird]

Thanks for that link, he does seem to have a very similar issue to be but unfortunately there is no fix mentioned.

[Freebird]

I think I put this plea in the wrong section, so am going to copy it into "Bike Help"

[z1bman]

anything more than 0.7 ohms is probably an open circuit. have you checked the rotor to see how strong the magnetism is ?

[KeithZ1R]

This is a good logical approach layed out well and is worth a look and definitetly worth following through ....

https://cdn.shopify.com/s/files/1/1091/ ... 9374954073

[chrisu]

I think I put this plea in the wrong section, so am going to copy it into "Bike Help"

moved and merged for you...................

[Freebird]

This is a good logical approach layed out well and is worth a look and definitetly worth following through ....

https://cdn.shopify.com/s/files/1/1091/ ... 9374954073

Excellent, thanks.

[Freebird]

Hi all

I have been having another play as none of the usual tests show any problems. It's a US import, so the headlight is on all of the time. I removed the fuse that protects the headlight circuit and voila, full charge was resumed at the battery.

I was surprised at the difference, does that sound normal?

Cheers

Glen

[Big Fluff]

The very first job is to disconnect the alternatr multi-pin plug, start the engine and measure the AC output between each 3 sets of 2 yellow wires. There's no point in starting at the battery etc, you need at least 50V AC at 4k RPM and over.
Only when you have this should you start looking at bad earths,and reg/rec problems.

[Mr Bump]

The very first job is to disconnect the alternatr multi-pin plug, start the engine and measure the AC output between each 3 sets of 2 yellow wires. There's no point in starting at the battery etc, you need at least 50V AC at 4k RPM and over.
Only when you have this should you start looking at bad earths,and reg/rec problems.

Like what he says....

Being a bit unscientific, in my experience a charging system that can't keep up with the lights = a lazy alternator.

[Freebird]

The very first job is to disconnect the alternatr multi-pin plug, start the engine and measure the AC output between each 3 sets of 2 yellow wires. There's no point in starting at the battery etc, you need at least 50V AC at 4k RPM and over.
Only when you have this should you start looking at bad earths,and reg/rec problems.

Yes, I did that and got over 50Vac across all 3, as stated in the opening post mate.