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Discussion Starter #1
I apologize in advance. This is a question about my wife's V-Star. It's been hard to start lately. The battery is obviously weak. We hadn't ridden for a while because it's been too friggin' hot. I start it weekly. It cranks slowly buy eventually catches and fires. I took it out yesterday and it died several times. Felt like it was starving at higher rev's then died at stop signs. I had to leave the key off for about five minutes before it had enough juice to start, I eventually got it home and let it idle for a bit in the garage. After that it would start instantly. Bad battery? I thought that once it was running you could pull the battery out. Of course...I guess the headlight/tail light/brake light might be a factor.

Thanks in advance.


Cheers,

SK
 

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On modern bikes you need a battery in the circuit for it to run. A shorted battery will not let the bike run.

Old bikes you used to be able to run without a battery I think.
 

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Just drag the battery to a chain auto parts store, get them to hook it to the machine, and they should be able to tell you pretty quickly if something major is wrong with it. If it's not that, check the voltage regulator, since most dead alternators are actually dead voltage regulators. If it's not that, start to look elsewhere.

To answer your question though, in theory, it is not necessary to have a battery in an alternator-powered electrical system once the engine is running. The battery is absolutely necessary to power the field windings while the engine is starting, which is why you can't bump or kick start a bike with an alternator if it has a dead battery, but IF there's never more current drawn than is being produced, a battery is not strictly necessary once the engine is running. That's a big 'if', though, because most bikes' alternators don't keep up with current draw at low RPMs, making a battery necessary to fill in the gaps.

Of course, if the battery has an internal short, all bets are off.
 

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Battery

My exp has been NO the bike will not run w/o a battery or w/ a dead one! I GUESS if you could kill the lights & all it might run if its warmed up, but forget pop starting it! Just bought a cheap little 150 Chinese scoot to get to the Bonne garage. 1 thing I really like @ it IS- the headlights etc wont work unless the scoot is running! MAkes starting a bit easier w/ a soso battery! As said MAGNETO!!!
 

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Discussion Starter #7
I love this forum!

I just wanted to thank everyone who responded. Now all I need to do is FIND the battery and then it's off to Auto Zone.


Cheers,

SK
 

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To answer your question though, in theory, it is not necessary to have a battery in an alternator-powered electrical system once the engine is running.
That all depends how the system is set up. On most bikes these days, the battery is part of the circuit such that the bike won't run without it, whether under minimal load, lights off, disconnected once running or whatever. As you say - a shorted battery certainly won't work.
 

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That all depends how the system is set up. On most bikes these days, the battery is part of the circuit such that the bike won't run without it, whether under minimal load, lights off, disconnected once running or whatever. As you say - a shorted battery certainly won't work.
Very true. I don't know how a V-star is wired, and now that you mention it, it's probably not possible on a modern Triumph twin either. Obviously anything with EFI is dead in the water. Yet another example of "theoretically", "practically", and "realistically" being three completely different things.

FWIW, I did push start my '50 Ford once (with the help of a really big hill) when it had a completely dead battery. It ran a generator instead of an alternator, though. I imagine that the same could be done with a bike if you could find a bike that runs a generator. It's definitely possible to push start anything that runs a magneto. If only it were worth it otherwise...

In conclusion, magnetos for all! (shudder)
 

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Yes indeed - the older stuff was set up such that the electrickery generator could power the whole system. I assume that was because batteries were still a bit iffy in those days - or maybe that's just how they felt like doing it at the time. :D
 

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In conclusion, magnetos for all! (shudder)
Man, I miss pulling up to a stop at night and having my headlight dim to nothing.

I guess we all enjoy the improved electrics on our bikes, but was it the right way to go? To the best of my knowledge, cars never had magnetos. Why did bikes adopt the system from cars? Why didn't magnetos evolve into something more efficient? I would love to be able to dig some old bike out of storage and be able to start it without worrying about the battery (fuel issues notwithstanding). That's why I like carbs better than EFI. Guess I'm just a conservative old fart.
 

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Discussion Starter #12
Magneto and Titanium Man...

Man, I miss pulling up to a stop at night and having my headlight dim to nothing.

I guess we all enjoy the improved electrics on our bikes, but was it the right way to go? To the best of my knowledge, cars never had magnetos. Why did bikes adopt the system from cars? Why didn't magnetos evolve into something more efficient? I would love to be able to dig some old bike out of storage and be able to start it without worrying about the battery (fuel issues notwithstanding). That's why I like carbs better than EFI. Guess I'm just a conservative old fart.
I miss my 1967 English home market version Daytona 500. It was so beautiful. English plates on the front and rear, it even had a badge on the oil tank, from Elite Motors. Sure it leaked and made my hands smell of petrol form the carb tickling; but it was so damn reliable. I loved it. I got knocked off it on Sunset Blvd, pre helmet law days. Typical Hollywood rocker acting like an idiot and getting hit by a car. The injuries to my bike and myself were nominal. I wound up selling it to an English guy who took it "home". Musicians often find themselves broke and in need of selling everything they own. Now I have day job...


Cheers,

SK
 

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Man, I miss pulling up to a stop at night and having my headlight dim to nothing.

I guess we all enjoy the improved electrics on our bikes, but was it the right way to go? To the best of my knowledge, cars never had magnetos. Why did bikes adopt the system from cars? Why didn't magnetos evolve into something more efficient? I would love to be able to dig some old bike out of storage and be able to start it without worrying about the battery (fuel issues notwithstanding). That's why I like carbs better than EFI. Guess I'm just a conservative old fart.
Up 'til the 1920s, most cars did run magnetos. They died out for a number of reasons, chief among them being lack of ignition advance in the early units. Motorcycles lasted a lot longer, with some H-Ds running them into the 80s, but the almighty alternator with its light weight and inexpensiveness eventually won out. Aviation engines still use them, because they're so damn reliable.

Unfortunately, adjusting them is a, uhh, much more mechanical procedure than most people would be comfortable undertaking, so an enthusiast market never developed.

I'd like to run carbs, mags, kickstart, and a small generator for lights. "Look, ma', no battery!" Motorcycles could be such simple machines if we'd let them... well... ignoring pollution controls they could anyway... but we'd have to collectively give up a few horsepower and a lot of convenience.
 
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