A 3 month old battery loses its charge with 15 miles

  • Jimbo68
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Re: A 3 month old battery loses its charge with 15 miles

10 Aug 2026 23:53
#926625
Great responses, thank you all.

Any thoughts please on starting the bike up with very little oil for 2 or 3 minutes to test the stator output voltage at 4000rpm?

Cheers
1981 Kawasaki KZ440-A2

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Re: A 3 month old battery loses its charge with 15 miles

11 Aug 2026 00:41
#926627
Great responses, thank you all.

Any thoughts please on starting the bike up with very little oil for 2 or 3 minutes to test the stator output voltage at 4000rpm?

Cheers
Don't do it, you will starve the top end of oil and possibly spin a bearing
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Re: A 3 month old battery loses its charge with 15 miles

11 Aug 2026 01:30
#926628
^^^ What Wookie said ^^^.   Oil is cheaper than damage caused by oil starvation.

   To clarify our suggestion above to tilt the bike opposite the cover being removed, it doesn't require much tilt for most or all the oil to evacuate from the cover being moved.  30° ~ 45° from vertical will almost assuredly be enough.

  A discussion was had here not long ago about re-using newish motor oil that had been run.  If desired, wipe the area around the drain pug, drain it into a clean container, cover it for the duration, then pour it into the motor when ready.  Filter through a couple layers of terrycloth to catch any sand sized particles if deemed necessary.

Good Ridin'
slmjim & Z1BEBE
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A Rider looks at your odometer and tags.

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Re: A 3 month old battery loses its charge with 15 miles

11 Aug 2026 04:43
#926633
Thank you both. Great advice.

If I start a new post about dropping a bike on to its right hand side, you’ll know what’s happened 🤣🤣.
1981 Kawasaki KZ440-A2

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Re: A 3 month old battery loses its charge with 15 miles

14 Aug 2026 01:24 - 14 Aug 2026 01:30
#926712
Hi folks.

I’ve reinstalled the stator and added the oil.

No gasket leak so far 😁
Bench test of the rectifier circuit was good 😁
Output voltage of the stator is 75Vac 😁

Here are the battery readings. I’d be grateful for your thoughts please. Is my replacement regulator doing its job?

1. engine off: 13.2V
2. @1000 rpm: 14.5V
3. @4000 rpm: 14.3V

Many thanks.

 
1981 Kawasaki KZ440-A2
Last edit: 14 Aug 2026 01:30 by Jimbo68. Reason: Typo

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Re: A 3 month old battery loses its charge with 15 miles

14 Aug 2026 01:36 - 14 Aug 2026 01:38
#926713
Those numbers are nominal.  Ready to test ride.  Well done.

Good Ridin'
slmjim & Z1BEBE
A biker looks at your engine and chrome.
A Rider looks at your odometer and tags.

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1973 ('72 builds) Z1 x2
1974 Z1-A x2
1975 Z1-B x2
1993 CB 750 Nighthawk
2009 ST1300A

www.kawasaki-z-classik.com
A Forum tightly focused on all things Z1 and Z2.
Last edit: 14 Aug 2026 01:38 by slmjim+Z1BEBE.
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Re: A 3 month old battery loses its charge with 15 miles

14 Aug 2026 02:28
#926716
Woo hoo!! Thank you!!

A huge thank you to everyone who contributed, advised, and guided. I could not have done this without you. Big up the KZRider forum!! You are amazing!!

Cheers!!
1981 Kawasaki KZ440-A2
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Re: A 3 month old battery loses its charge with 15 miles

14 Aug 2026 05:50
#926728
It’s a win:)
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Re: A 3 month old battery loses its charge with 15 miles

17 Aug 2026 05:02
#926830
Hopefully my final post on this topic…

A test ride of 9 miles followed by a 20 minute pause with the engine off. It restarted happily. I did another 8 miles and again, it restarted fine afterwards.

Just in time for the weather to change for the cooler. Sigh! 🤣🤣.

Cheers and all the best to y’all.

James
1981 Kawasaki KZ440-A2
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Re: A 3 month old battery loses its charge with 15 miles

17 Aug 2026 08:36
#926840
Here in Virginia fall is my favorate time of year for riding. Anything above 40 degrees F, I'm game for a ride. It makes ATGATT alot more comfortable. 
97 ZL600
94 VF750c
94 KE100
82 KZ305

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Re: A 3 month old battery loses its charge with 15 miles

17 Aug 2026 09:14
#926842
Good for you!!

Don’t the wet leaves, damp roads and low temps get you a bit jittery on your bike?

I think I’m too old and so much more risk averse than I was as a youngster 😁
1981 Kawasaki KZ440-A2

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