Had to take the car to work today...

[xifer]

Hi All,
Before I spend loads of dosh, am I missing anything?

Bike started running rough, wouldn't bump start, I figured
battery needs replacing, as does the chain.

Still original electrics reg/rect/ quite new points & condensors.

New chain and charged battery freed up loads of power (felt really
strong and smooth) but then yeach, morass of struggling cyclinders
again after about 10mins hard riding.

Read about jump starting of car batteries when the vehicle is running
being ''a bad thing'' and I did that very thing a few days before at
a petrol (gas) station. Guy in a jeep with 2 x stomping batteries
(80 amps!) and the enging going.

but the bike sounded rough before anyway and wouldn't bump start...



So I've had the multimeter out:


2500 rpm - 14.6 v DC

5000 rpm - 14.9 v DC

1000 rpm - 15v dropping back to 13.5 (letting go the throttle from 5000 revs)


I got only 8-12V AC on each of the generator outputs (should be 60V AC) so
I'm wondering how come I get such high charging voltage? Is it because
resistance is up and there is less current, therefore less power being generated
but same voltage?!

...and some 1000 ohms to earth from each phase wire (should be infinite?).

Reg and Rect seem ok continuity each way seemed ok but I'm not sure about diode testing.

So, I figure, if I keep the battery charged, it'll keep me going until
end of the month when I can afford new parts.

Despite charging battery overnight bike wouldn't start in the morning - seems it will only start on a hot day (higher atmospheric pressure or
just temp?).


I guess I need new alternator, battery, rectifier and probably regulator.
Of course I may be completly missing something?


any insight would be appreciated!

happy riding!

[earlfor]

Re: Had to take the car to work today...

If you only have 8 to 12 V AC on each phase of the stator, then the stator is faulty. As for why you have such a high DC charging voltage, voltage is electrical pressure, amperage is capacity. You could stack 10 AA flashlight batteries and get 15 volts, but you will not have enough capacity to start the bike.


Earl


[quote="xifer"]
I got only 8-12V AC on each of the generator outputs (should be 60V AC) so
I'm wondering how come I get such high charging voltage? Is it because
resistance is up and there is less current, therefore less power being generated
but same voltage?!

[SqDancerLynn1]

You 12v AC?? ARE you measuring between the wires? & not from ground?? with them disconnected from the reg.. Yes The resistance from the stator wire to ground should be infinite-- again with the wires disconnected

[xifer]

You 12v AC?? ARE you measuring between the wires? & not from ground?? with them disconnected from the reg.

Well they were not disconnected from the RR but they should
still be ~60VAC between the wires, right?

[earlfor]

NO. You must have the stator disconnected from the R/R and the bike running at 5k rpm to take the reading on the stator wires, Meter set to the AC 200 scale. If stator wires are numbered 1,2 and 3, the meter connections must be between 1 and 2 for phase 1, between 2 and 3 for phase 2 and between 1 and 3 for phase 3. Each phase should show 80v AC at 5k rpm.

Earl

Well they were not disconnected from the RR but they should
still be ~60VAC between the wires, right?

[xifer]

ok, sh&*t, thing is I couldn't see how to disconnect without
damaging the connectors so I just measured it. Don't
understand why the voltage shouldn't be about 60V anyway
but I'll go measure it again with the wires off.

[IanFrancisco]

I would replace the OE RR asap. Doesn't regulate the third phase of the alternator. Could save some headache down the road. Also a separate ground wire from RR neg. directly to battery neg. is good insurance.

[xifer]

So I disconnected the stator wires from the RR and I get
the same VAC as when they are connected. Lucky
for me there is only 8~12VAC on 2 phases so it doesn't
matter I cut the cables...

Why do people say the Stator needs disconnected from the
RR to measure the output? Its not required.

[SqDancerLynn1]

If the reg/rect is toast it could load the stator dropping the voltage. check & make sure you did not pinch the wires with the stator cover

[xifer]

If the reg/rect is toast it could load the stator dropping the voltage. check & make sure you did not pinch the wires with the stator cover

I'm not convinced that would drop the voltage. Current maybe.

Similar with testing batt charging voltage - waste of time. What you
need to do is check the current & the voltage. E.g. I had 14.8 volts
at the terminals but no charging power... as we all know:

POWER = VOLTS * AMPS

or POWER = AMPS * AMPS * OHMS

Fried electrics raises resistances

Volts = amps * ohms

increase the resistance and the _current_ drops - not the voltage.

Anyways, the stator and RR are indeed toast and new ones are on
order.