Re: Mother's Bike Comes Back to Life...now alternator theory

[jdubbs32584]

from experience...if the battery is completely flat then your FI monster won't run. if it will take a bit of a charge then you'll be ok, but if it won't take a charge then you need a new battery anyways

my XR will run with a dead battery, but the lights don't work that well, and it won't start again.

Yeah, thats what we think is going on.

We have one known good battery that works in both our bikes.

One older battery that sat for almost a year on no charger, never got turned on, nothing. That one is more than likely completely dead.

And one battery we don't know the history of (got from a friend) that is suspect.

If the stater (spelling?) was bad on my bike and not charging the battery, wouldn't the good battery have run dead by now?

I'm not technically proficient so I could be completely wrong. It just would seem super weird to me if both bikes had a bad stater or whatever.

[Mother]

I look at it just like a fire truck

Carbie will run directly off the hydrant

FI bike runs off the tank water and the hydrant refills the tank

Battery tester says both batteries are tits up

mystery solved

[Howie]

Why?

The stator has to put out enough to run the bike *and* charge the battery.

I've run FI cars with no battery before. . .

Cars have sufficient output at idle to run, most sporty bikes permanent magnet alternators don't driven off the crankshaft don't.  If you look at your car, you will see there is a difference in pulley size, and the alternator is spinning faster than engine speed.  Our Ducs and your KTM spin at crankshaft speed.  Take an inductive ammeter and measure output, you will see it is less than needed to run the fuel pump, FI and lights. 

[herm]

you da man howie 

[Mother]

Another lesson learned about motorcycle batteries

When your local shop says to charge at 1.5 amps

LISTEN

because attempting to charge at 200 amps is a poor choice

Now I have a new battery and a new Battery Tender Plus

[Grampa]

I happy to hear you found replacement batteries up in the woods. I was afraid you might have to resort to using potatos.

[Mother]

Didn't

had to go to that place where all them big boxes are lined up with the gooey gravel laid between 'em

and the christmas lights where those trails come together

full of all sort of folk all packed together

smells funy there

and

it's loud