Topic: 78 550K weak battery, runs crappy?

[ugmold550]

My battery is old in my 78 550K, It went dead once last season, but this year has worked ok. Temps are getting cooler and I started it up, ran down the road and it felt like I was running out of gas. Came home. Let it idle, was rough. Rev'd it up, it sounded ok. Idle again, stalled...battery dead. Took a charge. Haven't ridden since.

So I will be buying a new battery, just trying to figure out if this was the reason for how it was running.

Thanks-ugmold

[Deltarider]

Well, do inform us.

[ugmold550]

Sure, I'll report back next spring.

[jaytee-nz]

The search facility on this forum is always a good start when you have a problem that needs answering.
Here's a related old thread that should answer your question (hopefully a little bit more useful than Delta's response).
http://forums.sohc4.net/index.php/topic,157908.msg1810037/topicseen.html#msg1810037

[HondaMan]

Do you by chance have an electronic ignition like Dyna S in it? That will kill the charging in the 550, dead.

[RAFster122s]

Battery could just be going bad and not accepting a charge causing your running issues. Throw your old battery on the trickle charger and give it 24 hours, measure voltage before starting your charge. Then measure after coming off charge and then two hours later. This figures can help diagnose if you battery is toast or merely weak.  The Dyna S as HondaMan mentions is unkind to our old bikes because it consumes so much power. Trickle chargers won’t fully charge a deeply depleted battery in 24 hours, FYI it may take longer or charged at a little higher than a battery maintainer/trickle charge can do in a short period of time.
Just like on a car, a bike often won’t be able to stay running when the battery falls below a certain voltage, on some vehicles this is 10v, which is a severely depleted charge level. Sounds like your battery may be severely depleted or have a bad cell.
Need more information to help determine what is the problem...

[ugmold550]

I have points, aftermarket, with new condenser, installed this spring. I charged it on my trickle charger right after it went dead. Didn't check the voltage before or after. But it has been over 24 hours now. We had an incredible wind/rain storm, winds 80mph and it is still very windy, branches everywhere so I haven't had time to look.

Now this battery has to be 10+, maybe older. It has been great dry cell, I charge at the beginning and end of every season and store it inside on a dry shelf.
I don't think I have ever had a bike battery last so long. I had a 750 Nighthawk years ago that I was running on a low battery and it was pretty much the same scenario, I think it took out the stator as a result. Hope it is not the case. The bike always run decent, I drain the carbs every now and then, and for the winter.

Thanks much. I'll get back on the voltage.

Battery could just be going bad and not accepting a charge causing your running issues. Throw your old battery on the trickle charger and give it 24 hours, measure voltage before starting your charge. Then measure after coming off charge and then two hours later. This figures can help diagnose if you battery is toast or merely weak.  The Dyna S as HondaMan mentions is unkind to our old bikes because it consumes so much power. Trickle chargers won’t fully charge a deeply depleted battery in 24 hours, FYI it may take longer or charged at a little higher than a battery maintainer/trickle charge can do in a short period of time.
Just like on a car, a bike often won’t be able to stay running when the battery falls below a certain voltage, on some vehicles this is 10v, which is a severely depleted charge level. Sounds like your battery may be severely depleted or have a bad cell.
Need more information to help determine what is the problem...

[Bailgang]

Do you by chance have an electronic ignition like Dyna S in it? That will kill the charging in the 550, dead.

Huh? I had a dyna s in my 75 cb550 with stock coils and charging sys, it never had a charging issue during the 3 years I owned it.

[Ichiban 4]

With my '77 550K..whenever the battery is weak or run down it will misfire..sometimes not start at all if it's really run down.  I have a Dyna ignition on it now..but it did the same thing when I ran points and condenser.  I live in Colorado..and store the bike in unheated building.  Cold weather also hard on batteries here..unless they are relatively new and/or fully charged.  I always take battery out in winter anyway.  Don't ride much during cold-snowy weather anymore (never did ride much in winter here anyway).
Last 2-years..been running a high cranking (220 amp) glass-matt battery which works super. If you can get one..highly recommend it..for the 550's. 
Because the charging system on these bikes is barely adequate anyway.  Having the extra battery capacity..and keeping it charged-up when not riding seems critical.
It's all workable with these old 550's..I feel. Just have to apply the appropriate correctives..to maintain them as enjoyable riders. 
I still flash-back to early '70's sometimes..when I ride mine-first rode my first 550 BTW.
Cheers  Ichi

[Mr. Mike]

10 plus years old battery? Congrats on that, but I wouldn’t fool with it. I’d be in the market to replace it...they’re relatively cheap.

[ugmold550]

I checked the battery today after the trickle charge I did 2 days ago, it was 13.06V. Started it up, seemed normal, starter wasn't slow (although it hangs and misses, that's another story) Idle is around 12.5V and at 2k it is 13.6, so it seems to be charging. At idle I still hear the engine missing, which is another story. I thought the cam chain sounded loud too. I drove it around the neighborhood and it seems ok. But I am still suspicious of the battery. It is long overdue for a new one.