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Offline Art

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Re: Fan affecting charging system
« Reply #10 on: 02 October, 2020, 11:38:14 PM »
Do you think it might be the fan?

Offline imurray

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Re: Fan affecting charging system
« Reply #11 on: 02 October, 2020, 11:40:13 PM »
According to the mechanic the charging voltage drops below 12 when the fan turns on. I dont know enough about electrics to understand why the fan would draw more power than normal, I mean its either on or off?  :027:

Offline Art

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Re: Fan affecting charging system
« Reply #12 on: 03 October, 2020, 12:11:26 PM »
Yes the radiator fan motor is either on or off however like any other motor the more load its under the more power it will draw from the battery. Voltage test results need to be looked at as a complete test set and I'd expect to get the following results which would indicate that all is well.

12.6v Initial battery level of charge, dropping to...
12v with ignition & headlamp on for 2-4 minutes.
10.6v with the starter motor cranking the engine
13.2v with IGN & HL on and engine running at 2,500 RPM
14.2v with IGN & HL on and engine running at 5,000 RPM
12v after 5-10 minutes of idling at 1,200 RPM with IGN & HL on, dropping to...
11.8v at 1,200 RPM with IGN & HL on and the radiator fan motor running.

Note here if you're expecting the charging system to keep up with the draw from the HL and radiator fan with the engine idling at 1,200 RPM  (let alone with the heated grips too) your expectations are unrealistic, that's what the battery is for to act as a buffer. With the voltage having dropped to around 11.8v when the fan kicks in the real test is to rev the engine where you should be getting roughly what you got on the previous test above...

13.2v at 2,500 RPM with IGN & HL on and fan motor running.

Considering the radiator fan motor should only be running for a minute or two it should not put so much strain on the charging system to flatten the battery or does the fan run for longer extended periods of time?


Offline Shed

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Re: Fan affecting charging system
« Reply #13 on: 04 October, 2020, 06:07:15 PM »
Has your mechanic checked the condition of the wiring to and from the fan, and also the wiring to and from the fan relay, and the fan relay itself?

You may be better off with an auto-electrician, not a mechanic.

Offline JMCBF1000

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Re: Fan affecting charging system
« Reply #14 on: 04 October, 2020, 08:38:21 PM »
I am having a similar issue I guess, but I have no noticeable symptoms other than what seems to be random misfiring between 2000 and 3000 rpm under load and with engine warm.
Things seem to get worse when the fan kicks in and high beam is used (more misfiring/stuttering between 2k and 3k rpm, just after engine is warm).

So I decided to measure several parameters, and here is where I ask your opinion:

BATTERY TERMINALS:

Engine Off : 12.69 V
Engine Idle Warm :   13.58 V
Engine 5k Revs Warm : 13.8 V
Engine Idle Warm / Fan On : 12.77 V
Engine 5k RPM Warm / Fan On : 13.47 V

Start Engine : drop to 10.8 V

Engine Idle Warm + Fan + High Beam : 12.3 V
Engine 5K RPM Warm + Fan + High Beam : 12.85 V


While reving the engine above idle RPM up to 5000 rpm I notice just a small increase on the measured values.
I guess red values are too low...

STATOR OUTPUTS   

Engine Idle Warm : 9.2 Vac
Engine 5K RPM Warm  : 10.2 Vac

Here is where I think the problem is....
Shouldn't the sator have much higher AC output ? Around 30 to 50 Vac ?
I wonder how the R/R is still being able to put out 13.5V with these outputs from the stator ....

The system is much probably struggling to keep things running well when fan kicks in and high beam is on.
I guess the battery is holding things up and still being able to keep it's charge between 12 and 13 v.
Bike neved died on me but with this data I guess its time for a new stator, before being stranded one day on the road I guess...
2007 MKI Biffa, 31.000 miles. Using a MOSFET FH008DD R/R.

What do you think ?
« Last Edit: 04 October, 2020, 09:06:43 PM by JMCBF1000 »

Offline Crispy

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Re: Fan affecting charging system
« Reply #15 on: 04 October, 2020, 09:02:06 PM »
Hi JMCBF1000,

There’s a been a lot discussed on this forum about Mk1 CBF1000’s around a flat spot in the rev range you mention. Mine has a slight flat spot at about 2000rpm to 3000rpm but only when it’s cold. I’d use the search feature on the forum and search for flat spot There may be nothing wrong with your bike. A cursory look at the forum seems to suggest aftermarket cans/exhausts will solve the problem.
A day without learning is a day wasted

Offline Art

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Re: Fan affecting charging system
« Reply #16 on: 05 October, 2020, 07:28:54 AM »
*Originally Posted by JMCBF1000 [+]
Here is where I think the problem is....
Shouldn't the sator have much higher AC output ? Around 30 to 50 Vac ?
I wonder how the R/R is still being able to put out 13.5V with these outputs from the stator ....

What do you think ?

How good is your multimeter battery?

Yes, 40v AC is the typical output from a CBF1000 stator. Although you should be checking for three results (three pairings of the yellow output wires). Expect three equal results around 40v AC. I think you should first replace the battery in your multimeter and then test the charging system from the beginning using ElectroSport's fault finding flow chart for motorcycle charging systems here

Don't just jump in and replace the stator, follow the flow chart and prove any fault

Offline JMCBF1000

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Re: Fan affecting charging system
« Reply #17 on: 05 October, 2020, 12:07:51 PM »
Hello ART,

Thank you for your valuable information.
I tested the values with another multimeter (to dissipate any doubt about the multimeter), and when cold, folowing the Electrosport's fault finding flow chart, it finishes right away with a perfectly OK charging system since the voltage is higher than 13.5V at 2500 rpm and lower than 14.8V at 5000 rpm.

I guess things change a litte bit after the engine is warm and when the fan kicks in, having 12.77V measured at the battery (12.3 V if I turn High beam on ...), and this is when i start to have occasional misfires between 2000 and 3000 rpm.

Other thing that puzzles me are these readings :

Stator AC output (so low ? Reving the engine does not change these readings ...)



R/R output (How come with the previous AC readings I have this ok R/R output value ?!!)


Am I missing something ?

Thanks!
« Last Edit: 05 October, 2020, 12:14:02 PM by JMCBF1000 »

Offline Art

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Re: Fan affecting charging system
« Reply #18 on: 05 October, 2020, 01:48:07 PM »
Don't back probe the stator output connector, disconnect the connector and make a good temporary connection direct into the connector terminals. With the engine running at 5,000 RPM check the stator output between terminals A-B, A-C and B-C expect three equal readings of around 40v AC.

Your probably only getting 10v AC from the stator because your testing the output with the engine idling at 1,200 RPM. Its a three phase stator so 3 x 10 = 30v AC going into the RR and 13.9v DC coming out.

Offline JMCBF1000

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Re: Fan affecting charging system
« Reply #19 on: 05 October, 2020, 08:45:11 PM »
Hi ART,

You were absolutely right, backprobing the stator outputs while connected to the R/R gives a false reading that I can not explain (10V ...).

Unplugging the stator connector from the R/R and starting the bike imediately shows the reading below at each wire combination at ide :



Reving the engine the AC voltage goes up to 40 Vac or more.

So, thank you by the help, I now know how to properly test a charging system!

It is all ok with the stator, so i guess i will start to look at coils or damaged plug cables to see if i can find why i have these random misfires between 2 and 3k rpm under acceleration after the engine is warm.

Best to you all!