[Degsy]

Please warn me next time you're gonna do that. My brain just exploded.

Degs

Originally posted by Honclfibr
Since we're kind of on the topic of charging systems, here's a question that always pestered me...why are motorcycle charging systems called stators? From what I remember about car alternators, the stator is the 3 stationary windings arranged radially inside the alternator around the rotor, an iron shaft with windings that rotates at engine speed to create AC currents through the stator. Since there are 3 windings, you have 3 phase AC, which is regulated by a 6 diode bridge to give you DC with a half-ripple with 6 peaks per engine rotation. Correct me if I've misremembered any of this.

So why are motorcycle alternators just called "stators"? Do they not have rotors? How else would they generate an AC current in the stator?

[Honclfibr]

Originally posted by Degsy
I beg to differ. Start your bike then disconnect the battery. You won't get very far before the bike dies. A stator will not run your bike for very long with no battery.

Derek

I know you've got a good deal more bike experience than me, so I'm not gonna shoot myself in the foot by saying you're wrong about this, but...it doesn't make much sense to me. If your bike relies on constantly discharging your battery, how is it that the battery stays charged? For that matter, this would seem to imply that my bike would not stay running if I jump a dead battery...which is *worse* than no battery because now my stator is diverting current to charge the battery as well, which is a heavier load on it than no battery at all.

The only thing I could think of is that the AC ripple off the stator is too severe, and so the battery is used similar to a filter capacitor, to smooth out the dips. Seems like an awful strain to put on your battery to have it constantly charging and discharging though, and I wouldn't expect the ripple to be that extreme that your bike would die...

[Degsy]

I don't know whay it;s called a stator rather than an alternator. as far as I am concerned they're almost the same thing. The trouble is, when the rotor isn't spinning fast enough to produce enough current for the spark, the motor dies. MCBGTI probably finds that his bike dies while it is sitting there idling. After a while, even if you hammer the hell out of the bike all the time, I THINK the bike would still die with no battery as there will be some loss from the system. I don't think that a total loss electrical system is just a motor with the battery removed. I'm no brainiac, so I could be full of crap actually, anyone else wanna chime in here?

Degs

[Honclfibr]

Now that I think about it, I must be wrong. You motorcycle racers are all obsessed with cutting weight, right? So if you could run without a 5-10 pound battery, certainly you would...I always thought you guys did, and just jumped the thing with a pair of insulated wires to get it started. I guess I made all that up

[Degsy]

Simplified (for me, not you).

1. Battery supplies initial charge for starting the motor (draws 3 amps while running for arguments sake)
2. Stator magically produces power (2 amps current at idle)
3. battery uses stator to keep charge when revs are low, voltage regulator makes sure everything stays arounf 14v or so?

Am I close, I dunno.

I just think that if you disconnect the battery, something's gonna go out of whack and the bike will die.

Degsy

[Degsy]

Originally posted by Honclfibr
Now that I think about it, I must be wrong. You motorcycle racers are all obsessed with cutting weight, right? So if you could run without a 5-10 pound battery, certainly you would...I always thought you guys did, and just jumped the thing with a pair of insulated wires to get it started. I guess I made all that up

Degs

[oreo_n2]

Originally posted by Honclfibr
Now that I think about it, I must be wrong. You motorcycle racers are all obsessed with cutting weight, right? So if you could run without a 5-10 pound battery, certainly you would...I always thought you guys did, and just jumped the thing with a pair of insulated wires to get it started. I guess I made all that up

i guess so. how do you explain my fiddy running with just a kick start (most of the time ) and no battery.

[Degsy]

Doesn't that have some kind of dynamo?

Maybe not.
I dunno

Degs

[oreo_n2]

whats a dynamo?
i dont think its anything special, once you force the motor to turn, the coil charges, til the points open and the air in the chamber around the plug breaks down and sparks, then the inertia(?) of the flywheel keeps that bugger turning so the coil can charge again, until the points open again and the same occurs again... no charging system at all... no lights or fuel pumps or fancy computers for fuel injection or nothing, just the ignition system on this puppy.

the lack of a fuel pump prolly has something to do with why it stalls after a just a few seconds with the front wheel in the air.

[Honclfibr]

Originally posted by Degsy
Simplified (for me, not you).

1. Battery supplies initial charge for starting the motor (draws 3 amps while running for arguments sake)
2. Stator magically produces power (2 amps current at idle)
3. battery uses stator to keep charge when revs are low, voltage regulator makes sure everything stays arounf 14v or so?

Am I close, I dunno.

I just think that if you disconnect the battery, something's gonna go out of whack and the bike will die.

Degsy

You're pretty much spot on. The battery does suppy the current necessary to turn the starter motor and get the engine turning. The stator produces power by rotating a magnetic field around the stator windings...what's important here is that the voltage out of the stator is dependent on the magnetic field produced in the rotor (and engine RPM speed), which in turn is dependent on the amount of current going through it. That's how the voltage regulator works. It measures the voltage output of the stator, and if it's too low, it allows more current to flow to the rotor; if it's too high, it allows less. This regulates the voltage output of the stator so it's not too high (blow components) or too low (bike won't run). As long as the stator voltage is higher than the battery voltage, the stator will charge the battery, and the battery will do nothing.

But what you're saying is valid, there is a limit to how much current the stator can source, and that limit decreases at lower RPMs. If you try to draw more current than the stator can supply, the voltage will drop. If it gets below the battery voltage, the stator stops charging the battery and isntead the battery runs the electrical/ignition systems. Now, I was under the impression that the stator would be able to supply enough current even at low RPMs, but I could be wrong. I'm just headed out to put my carbs back on, while I have the bike apart I will do a little experiment and pull the battery cable while the bike is running.

[Honclfibr]

If my experiment goes well, maybe you pull the battery next race day, save a few pounds, shave a few seconds, few extra trophies LOL?

[Degsy]

OK, I'm interested to see what happens. Don't put it in your mouth.

Degs

[McBiggity]

wow- i go away for 30 minutes and look what happens!!!
Got a new battery- it's charging now- See how that goes once it goes in. So it it still dies after starting, I'll re-build the carbs. And then see what happens.

[Degsy]

See if it dies after starting. If it does, try to start it again. If you get the clicking sound, then you have a busted voltage regulater or a short somewhere killing the battery, you might have blown the second battery and you might not have, pot luck really. If the bike tries to start after dying (motor turns over) then the battery is fine and you are looking at carbs, fuel, air, something other than battery.
Degs

[McBiggity]

ok-looks like I may have a busy weekend working on the bike.
If it's not the battery and it still dying- I will provide an excessive amount of beer and food for anyone that wants to help me out.

[rocker]

excessive beer supply mmmmmmm

[McBiggity]

think I found it- Okay- there is a fuel line of some sort that comes up between the carbs- right in the middle- It's not attached to anything!!!!!! where the hell does it go. It's only about 3 inches long- can't find anything to plug it into. There are two fule lines that come up from the middle of the carbs- one goes to the fuel on-off-reserve switch on the tank- the other I don't know where it goes.

[stoinkythepig]

that'd be the vent. Leave it as is.

So why are motorcycle alternators just called "stators"? Do they not have rotors? How else would they generate an AC current in the stator?

That's the function of the differential fornicator, duh!

[McBiggity]

ok- so that's the vent. It was spewing fuel when the engine was running before. What does that mean?? Excuse me for being dumb about bikes

and anyone in the area is more than welcome to come by tomorrow to help me

Tomorrow night we will also be having a little beer pong tournament on our custom beer pong table.

[oreo_n2]

beer pong?

where is dudley mass?

no wait, going to brewstock tomorrow.
next time.

[McBiggity]

Okay- New battery is charged- Bike wants to turn over but won't.
I think it may be flooded.- How do you de-Flood?

[McBiggity]

it was flooded- runs great now. Thanks for putting up with all my ????

[stoinkythepig]

If fuel was splilling out of the vent you have or had a stuck float valve. This may have caused fuel to fill one of the cylinders and that would stop the engine from turning (hydrolocking) over until the fuel leaked by the valves and rings. This may be why the bike would not start before.

You may want to replace the float valves in the carbs and change the motor oil. If the engine was indeed hydrolocked, your motor oil is diluted with gasoline. That said, if you've already ridden it for over an hour since the problem occured, the fuel is likely all evaporated.

[McBiggity]

it's been running good since I cleaned the carbs out real well yesterday. I took the day off from work today to make sure it was still running well.

[scootertrash]

Originally posted by mcbgti
.....I took the day off from work today to make sure it was still running well.

The sacrifices we make for the good of our bikes...