Author Topic: 76 F1- Battery Dead After Short Rides/Idling  (Read 347 times)

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Offline AP1

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76 F1- Battery Dead After Short Rides/Idling
« on: July 10, 2019, 07:01:36 pm »
Hello everyone. My Super Sport started out with a freshly charged battery about 2 weeks ago. Since then, I have started and let the bike idle for about 4 or 5 separate times for about 5 minutes or less. I have also taken it on 3 short (less than 3 miles) and low speed rides. I attempted to start the bike again yesterday and the battery was dead. I kickstarted it and read voltage at idle was about 11. At 2500-3000 voltage read 13.46. Does this sound like a charging system issue? Bad battery issue? Or lack of riding issue? Any help is appreciated. Thank you
1976 CB750f
1980 CX500c
2001 XR650r SM
2008 XR650l

Offline BRG-BIRD

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #1 on: July 10, 2019, 08:21:27 pm »
I would charge the battery fully then check the charging system at 3k and up to 4K rpms, it should be around 14.5 volts at 4K rpms. IMO what you described is lack of riding and idling. Idling will actually discharge your battery. Report back on what you find.
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Offline Patrick

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #2 on: July 10, 2019, 08:38:57 pm »
Your bike only really starts charging over 3,000 rpm. If you've been idling it with the lights on, you've been running on the battery. Take it for a ride and see if it charges.

Patrick
1970 CB750 K0
1982 VF750S Sabre
1987 VT1100 Shadow
1979 Yamaha XS11
1969 Yamaha DT1B
etc.

Offline scottly

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #3 on: July 10, 2019, 10:09:07 pm »
Or lack of riding issue? Any help is appreciated. Thank you
Lack of riding issue. ;)
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Offline ekpent

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #4 on: July 11, 2019, 04:07:23 am »
 You said freshly charged but did not say how old the battery is. I assume were talking a lead/acid.

Offline Robbo

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #5 on: July 11, 2019, 04:25:37 am »

Fully charge the battery.

Take it off the charger and leave it resting overnight.

What is the battery voltage reading the next day?


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1973 CB350 Four, 1975 CB550K

Offline AP1

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #6 on: July 11, 2019, 04:55:25 am »
You said freshly charged but did not say how old the battery is. I assume were talking a lead/acid.
Previous owner stated the battery is “fairly new” so I’m assuming it has been replaced within the last 2 years. And yes, lead/acid


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1976 CB750f
1980 CX500c
2001 XR650r SM
2008 XR650l

Offline 1976cb750f836

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #7 on: July 11, 2019, 06:29:55 am »
Mine doesn't charge below 3K. Gotta ride at 4K or above 8-10 miles. Put a VM on bat, and let idle, watch volts, then slowly rev up to 4K and watch.

Offline TwoTired

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #8 on: July 11, 2019, 08:17:21 am »
If you want to idle stationary, remove the headlight fuse while doing so. (and fan the air cooled motor)  That should relieve the alternator load enough so the battery can charge at very low RPMs.  When the charging system was originally introduced, the bike had a headlight switch.  This was before govs mandated headlight on all the time for MCs.  Newer Honda models still had the same alternator design.

With full electrical load, the battery doesn't charge much if at all, since the alternator makes about 1/3 of full potential at idle RPM.

Also, don't ride it like a Harley.  These engines thrive on RPM.  Lugging them at low RPM isn't doing them any favors.

You can find the "breakpoint" for battery charging on your particular bike, by attaching a voltmeter to the battery terminals and watching for voltage trend with RPM.  Battery will slowly raise the battery voltage when the alternator RPM spins fast enough to power both bike and have enough extra to charge battery.

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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline ekpent

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #9 on: July 11, 2019, 08:42:41 am »
 A member here from Texas,Hi Steve,has a motto. "Never believe a seller". Make sure the battery is good before chasing your tail too much and if its fine follow the other suggestions.  Did the seller say if he kept it on a tender once in awhile.

Offline AP1

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #10 on: July 11, 2019, 01:28:20 pm »
Thanks for all the input everyone. I put a charged battery back in today and rode around for about an hour at mostly highway speeds. Came home and checked voltage and it is holding strong at 12.10v bike off. I think I killed the battery the first time from letting it idle over and over. Thanks for alleviating my worries.


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1976 CB750f
1980 CX500c
2001 XR650r SM
2008 XR650l

Offline Patrick

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #11 on: July 11, 2019, 01:37:57 pm »
You still need to check your charging system. A battery should have a resting voltage of about 12.7v. If it is less, you still may not be charging correctly. Put a multimeter across the battery and check the charging voltage at several rpms. If it never approaches 14.7v charge rate, you need to dig deeper. Check all the connections for corrosion.

Patrick
1970 CB750 K0
1982 VF750S Sabre
1987 VT1100 Shadow
1979 Yamaha XS11
1969 Yamaha DT1B
etc.

Offline Robbo

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #12 on: July 11, 2019, 02:41:33 pm »
Thanks for all the input everyone. I put a charged battery back in today and rode around for about an hour at mostly highway speeds. Came home and checked voltage and it is holding strong at 12.10v bike off. I think I killed the battery the first time from letting it idle over and over. Thanks for alleviating my worries.


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If its resting voltage is 12.1 volts, that battery is done.  Time to replace it.




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1973 CB350 Four, 1975 CB550K

Offline Patrick

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #13 on: July 12, 2019, 08:26:23 am »
I wouldn't write off the battery until I had tested the charging system. If the bike isn't charging correctly and he continues to run on the battery and not the alternator, he very well could have a low charge at the end of a ride.

Patrick
1970 CB750 K0
1982 VF750S Sabre
1987 VT1100 Shadow
1979 Yamaha XS11
1969 Yamaha DT1B
etc.

Online Don R

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #14 on: July 12, 2019, 01:32:19 pm »
 My F1 still had the turn signal beeper, when it started sounding sickly I knew it was time for a trickle charge.
If the things you own end up owning you, it's better to be owned by some cool things.

Offline Mr. Mike

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Re: 76 F1- Battery Dead After Short Rides/Idling
« Reply #15 on: July 14, 2019, 06:17:01 pm »
You said freshly charged but did not say how old the battery is. I assume were talking a lead/acid.

As well as checking/maintaining the water level.
2002 Electra Glide
1978 750K
1966 CL77 (sold)

 

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