Bike drops to 6 volts or less when running

[luke]

1980 special (bobber now) New wiring new mikes xs battery...not sure where to start with this one..
Bikes fires first kick now and idles fine but headlight go very dim within seconds and the bike takes an immediate voltage drop to 6 or less..measuring voltage at the battery
Any ideas?

 

[rwingsfan]

Bet it runs like crap at 6 volts. Those TCI's are wanky about voltage. Sure your battery is ok? Mikes has had problems with the batteries before. I will never buy one there again. Even if it shows 12v at rest does not mean its not bad. Beyond that better start looking into your charging system.

 

[luke]

So I tested the rotor i have a reading of .8 ohm. I realize this means the rotor is bad but could a bad rotor cause this severe of a voltage drop?

Sorry if this is a dumb question just tryn to educate myself

 

[rwingsfan]

In my book there are no dumb questions. And yes if your rotor says .8 ohms it is bad and there is your starting point. When you test for voltage across your battery terminals what does it read? It should read around 12v at idle and increase to 13.5 or so at 2500 rpm but should not exceed 14v. Time to replace that rotor.

 

[xjwmx]

It should read around 12v at idle and increase to 13.5 or so at 2500 rpm but should not exceed 14v.

Should read over 14 at 3000 with good battery but never go to 15.....

 

[rwingsfan]

ya sorry my last post was a typo....do not exceed 15v. Mine tends to run around 14.5 at good throttle, but then again I did the permanent magnet conversion, well worth the effort.

 

[xjwmx]

I would do the conversion, but still using a battery. Electric start is good to have sometimes. But would like to be able to start and run with a completely dead battery.

 

[rwingsfan]

You do not have to run batteryless for PM conversion. I still run a standard battery, even though I am kick only....

 

[xjwmx]

If the battery is dead flat will it kick and run?

 

[jayel]

no it has to have battery to energize the stator coils to make electric to charge the battery to run the ignition ...no battery no run
Catch-22 you can't get there from here

 

[rwingsfan]

jayel....good to see a Iowa guy here, I am up in Dead Moines. Well you got to have enough juice to get your ignition going.

 

[xjwmx]

You've got magnets instead of a stator coil, right?

 

[XSLeo]

Take your battery to a place that sells batteries and get it load tested. Replace the rotor. Gary at Custom Rewinds 1-800-798-7282 He'll fix you right up $125 + s&h If it's there he even loans the right puller.
An 80 uses the combo reg/rec. The reg half can't be tested, but the rec half can. Check the rec. The repair manual explains how.
Jayel, in the stock system the battery energizes the rotor, not the stator. The rotor excites the stator to make electricity.
In a P/M system you can set it up with out a battery. With a battery it can still be started with a low or dead battery. I had an old &5 kawasaki H1 500. If the battery was dead it would start by turning on the key then with the kill switch off kick until the neutral light glowwed. Turn the kill on then it would start. Or unhook the battery, start it and rehook the battery.
The dead battery took all the alternator put out untill it had enough charge so it could fire the CDI as well as charge the battery. I assume the P/M on a 650 would act the same.

 

[xjwmx]

The rotor excites the stator to make electricity.

Yes, that's the three white wires from the stator carrying different phases to the regrec. I haven't investigated pm systems much. Seems funny not to have designed it to be pm though, especially when the first iterations of the motor were kick only.

I fixed what I was hoping wasn't a blown tach gear or oil pump something that was whining. Put a dab of grease in the bottom housing of the cable. My good deed to the xs for today.