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Motorcycles » rec.motorcycles.tech » nighthawk 550 electrical problem
| nighthawk 550 electrical problem [message #460942] |
Tue, 04 October 2005 00:56 |
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krusty kritter Wrote:
> jlpridge wrote:-
>
> My suspicions are confirmed. I waited a couple of hours and
> went out and pulled the cover to inspect the pulse generator. There
> was
> some corrosion around where that bad pickup bolted in. I cleaned that
> area up good and tested the resistance and it was in specs. I figured
> problem solved but found out while riding that as soon as the bike
> heated up good the problem (running rough and missing) returned. Sure
> enough upon testing the resistance on the two pickups the same one
> was
> bad. Any thoughts you have on this are greatly appreciated.-
>
> Well, that explains mysterious intermittent rough running.
>
> The pulser coils wouldn't be grounded to the frame, both wires would
> go
> to the ignition control module. As the rotor on the right hand end of
> the crankshaft passes each pulser coil, a short pulse goes to the
> ignition unit. It's only about 2 volts, but that's enough to trigger
> TWO spark plugs to fire. The engine fires TWO cylinders each time a
> pulser coil makes a spark, but only one of the two sparks is useful,
> the spark that's occuring while the exhaust valve is open is called a
> "waste" spark.
>
> The pairs of cylinders fired are 1 and 4, then 3 and 2, since the
> pistons are on opposite strokes 180 degrees apart. You should be able
> to tell which cylinders aren't firing by looking at the spark plugs. A
> cylinder that's not firing will have black sooty spark plugs.
>
> If one pulser coil is opening up when it gets hot, you can check to
> see
> if
> there's a problem in the connectors and wiring, you can even pull on
> wires to see if the insulation stretches out. That indicates a broken
> wire inside the insulation. If you can't find anything external, the
> open circuit is inside the pulser coil itself.
>
> If you can get the pulser coil problem fixed and the engine runs
> smoothly so it will rev up to 5000 to 7000 RPM you can do the open
> circuit voltage test again. The 1 volt that you got wasn't impressive.
> I suggest that when you get the engine to run on all four cylinders,
> remove the alternator cover so you can see the cooling fan. If it
> doesn't turn when the engine is running, then the alternator cannot
> generate AC current.
>
> The CB-650 Nighthawks had an excited field alternator with brushes.
> There was no cooling fan, you would spot that right away, and you'd be
> able to see the brushes. The voltage regulator sends battery voltage
> through the brushes into the rotor, making an electromagnetic field.
> When the rotor turns, that's what makes the voltage.
>
> A permanent magnet alternator, OTOH, has very strong permanent magnets
> that induce the electricity in the stator. But the rotor absolutely
> must *turn* when the engine is running to generate electricity!
Krusty,
I am going to purchase a stator for this bike. I have
reached this decision because of the test results from the Clymer
manual. There are five leads coming from the stator, 3 yellow, one
white and one black. The resistance tests for the three yellow leads
test within specs. However the test of the resistance between the white
and the black lead failed. The result in specs would be 4-6 ohms whereas
mine measures 1 ohm. And of course it failed the open circuit test you
had me do. Do you have any other advice before I replace this stator. I
have found a company who rebuilds them for less than $100 including
shipping with a 1 year warranty.
Jeff
--
jlpridge
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| Re: nighthawk 550 electrical problem [message #460943 ] |
Tue, 04 October 2005 06:06 |
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jlpridge <jlpridge.1wcz8g [at] news.motorbikebanter.com> wrote in
news:jlpridge.1wcz8g [at] news.motorbikebanter.com:
>
> krusty kritter Wrote:
>> jlpridge wrote:-
>>
>> My suspicions are confirmed. I waited a couple of hours and
>> went out and pulled the cover to inspect the pulse generator. There
>> was
>> some corrosion around where that bad pickup bolted in. I cleaned that
>> area up good and tested the resistance and it was in specs. I figured
>> problem solved but found out while riding that as soon as the bike
>> heated up good the problem (running rough and missing) returned. Sure
>> enough upon testing the resistance on the two pickups the same one
>> was
>> bad. Any thoughts you have on this are greatly appreciated.-
>>
>> Well, that explains mysterious intermittent rough running.
>>
>> The pulser coils wouldn't be grounded to the frame, both wires would
>> go
>> to the ignition control module. As the rotor on the right hand end of
>> the crankshaft passes each pulser coil, a short pulse goes to the
>> ignition unit. It's only about 2 volts, but that's enough to trigger
>> TWO spark plugs to fire. The engine fires TWO cylinders each time a
>> pulser coil makes a spark, but only one of the two sparks is useful,
>> the spark that's occuring while the exhaust valve is open is called a
>> "waste" spark.
>>
>> The pairs of cylinders fired are 1 and 4, then 3 and 2, since the
>> pistons are on opposite strokes 180 degrees apart. You should be able
>> to tell which cylinders aren't firing by looking at the spark plugs. A
>> cylinder that's not firing will have black sooty spark plugs.
>>
>> If one pulser coil is opening up when it gets hot, you can check to
>> see
>> if
>> there's a problem in the connectors and wiring, you can even pull on
>> wires to see if the insulation stretches out. That indicates a broken
>> wire inside the insulation. If you can't find anything external, the
>> open circuit is inside the pulser coil itself.
>>
>> If you can get the pulser coil problem fixed and the engine runs
>> smoothly so it will rev up to 5000 to 7000 RPM you can do the open
>> circuit voltage test again. The 1 volt that you got wasn't impressive.
>> I suggest that when you get the engine to run on all four cylinders,
>> remove the alternator cover so you can see the cooling fan. If it
>> doesn't turn when the engine is running, then the alternator cannot
>> generate AC current.
>>
>> The CB-650 Nighthawks had an excited field alternator with brushes.
>> There was no cooling fan, you would spot that right away, and you'd be
>> able to see the brushes. The voltage regulator sends battery voltage
>> through the brushes into the rotor, making an electromagnetic field.
>> When the rotor turns, that's what makes the voltage.
>>
>> A permanent magnet alternator, OTOH, has very strong permanent magnets
>> that induce the electricity in the stator. But the rotor absolutely
>> must *turn* when the engine is running to generate electricity!
>
> Krusty,
>
> I am going to purchase a stator for this bike. I have
> reached this decision because of the test results from the Clymer
> manual. There are five leads coming from the stator, 3 yellow, one
> white and one black. The resistance tests for the three yellow leads
> test within specs. However the test of the resistance between the white
> and the black lead failed. The result in specs would be 4-6 ohms whereas
> mine measures 1 ohm. And of course it failed the open circuit test you
> had me do. Do you have any other advice before I replace this stator. I
> have found a company who rebuilds them for less than $100 including
> shipping with a 1 year warranty.
>
> Jeff
>
>
Jeff,
Was it determined that this is an excitable field alternator with brushes?
pierce
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| Re: nighthawk 550 electrical problem [message #460945 ] |
Tue, 04 October 2005 06:45 |
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jlpridge wrote:
> I am going to purchase a stator for this bike. I have
> reached this decision because of the test results from the Clymer
> manual. There are five leads coming from the stator, 3 yellow, one
> white and one black. The resistance tests for the three yellow leads
> test within specs. However the test of the resistance between the white
> and the black lead failed. The result in specs would be 4-6 ohms whereas
> mine measures 1 ohm. And of course it failed the open circuit test you
> had me do. Do you have any other advice before I replace this stator. I
> have found a company who rebuilds them for less than $100 including
> shipping with a 1 year warranty.
Well, $100 for a stator sounds like a good deal, if you really *need*
the stator. Have you pulled off the alternator cover to see if the
rotor is actually *turning* when the engine is running? It's possible
that the rotor isn't turning, or that what you actually have is an
excited field alternator with brushes.
If you take off that alternator cover, you'll either see a cooling fan
(like in the parts fiche at www.partsfish.com) or you'll see the
rigging for brushes.
An excited field alternator won't pass the charging voltage test or the
open circuit test if it's not getting DC voltage from the battery,
through the brushes, to the rotor.
Another guy had a CB650 and he was having problems and he also
mentioned black and white wires going to his alternator. Those were the
wires from the voltage regulator to the brushes.
I'm curious as to what the black and white wires you mention are for.
The only other thing I can think of is that your ignition system is not
just a transistor ignition but is actually Honda's so-called "CDI"
ignition system.
If that's what it has, the black and white wires could be coming from a
winding in the stator that puts out 50 to 100 volts to provide high
voltage to the CDI module.
If your motorbike has a CDI ignition system, you wouldn't get 12 volts
on the ignition coil positive terminals when you turn the ignition key
on, you'd get 50 or 100 volts when the engine was running and less when
you were cranking the engine with the starter.
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