BMW K bikes (Bricks)


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TheGreatMorten

TheGreatMorten
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Hello
I was wondering if i was so lucky, that anyone in here would drive with a 4xxx Acewell? That could share your configarations in the speedometer :-)
I got the correct RPM and speed, but the fuel indicators is teasing me.. and would be nice just to compare if you have picked the same stuff 
¨
I know that im suppsed to pick 100k Ohm, but it just shows me a full tank (which would be nice if it was correct) I dont know if i should pick anything else in the menus? Also i have another fuel cap on the tank (CNC café made) but that shouldnt be an issue

Looking forward to hear from you :-)

Best Regards
Morten

    

Inge K.

Inge K.
VIP
VIP
The signal from the level sensor is reversed compared to what's normally used.
You must reverse the coil inside the tank.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

TheGreatMorten

TheGreatMorten
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Inge K. wrote:The signal from the level sensor is reversed compared to what's normally used.
You must reverse the coil inside the tank.

thanks for fast answer.. but wtf that sounds strange :-)

    

Inge K.

Inge K.
VIP
VIP
It's 110 Ohm when empty and 3.5 Ohm when full.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

TheGreatMorten

TheGreatMorten
active member
active member
Sorry for the long reply Razz

I could simply connect the wires, that went up to the OE fuel gauge streight to the Acewell. It Works perfectly

    

Laitch

Laitch
Life time member
Life time member
TheGreatMorten wrote:It Works perfectly
Does Works perfectly mean that as the tank gradually empties, one bar after another disappears from the display or does it mean that at a certain point all the bars disappear from the display indicating there is a liter or less fuel in the tank?

How long has it been working perfectly?


__________________________________________________
1995 K75 90,000 miles
    

TheGreatMorten

TheGreatMorten
active member
active member
Laitch wrote:
TheGreatMorten wrote:It Works perfectly
Does Works perfectly mean that as the tank gradually empties, one bar after another disappears from the display or does it mean that at a certain point all the bars disappear from the display indicating there is a liter or less fuel in the tank?

How long has it been working perfectly?



As number 1. one bar after eachother untill its emty.

I tryed wireing it into the BEP, but that only showed full, or startet to blink at 4L left.. When i wired it streight to the Acewell it worked as supposed to, with all the bars. Ofc, i had to set the speedometer at 100ohm



Its been working since May where i got the Acewell Very Happy

    

Laitch

Laitch
Life time member
Life time member
TheGreatMorten wrote:Its been working since May where i got the Acewell Very Happy
cheers


__________________________________________________
1995 K75 90,000 miles
    

Salim

Salim
New member
New member
Hi Guys sorry for opening a long subject again but need urgent help in a similar mater.
As I am loosing my mind in my project.
I have a k75s 1992 installed the bep3.0 on the original wire harness and hooked on a chinese speedometer/tachometer following the outputs of the bep3.0.
All is working fine except for rpm reading I hooked the rpm out on the bep3.0 to the Chinese tachometer and nothing is happening all other features are working.
I am about to drop the hole project need your help as I barely understand technical vocabulary.

    

Laitch

Laitch
Life time member
Life time member
Salim wrote:All is working fine except for rpm reading I hooked the rpm out on the bep3.0 to the Chinese tachometer and nothing is happening . . . 
If you programned the instrument for the number of cylinders, which number did you use?


__________________________________________________
1995 K75 90,000 miles
    

robmack

robmack
Life time member
Life time member
That Chinese gauge expects the tach input to swing symmetrically around ground, but the BEP sends a positive square wave signal only. You'll have to add a 0.2uF capacitor in series with the tach output of the BEP, and a 2Kohm resistor between the output of the BEP and ground. That circuit will shift the signal and the tach will work.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Salim

Salim
New member
New member
Thanks robmak really appreciate do you have a picture or drawing?
Do I need to program the tachometer for 1/2or 4 cylinder?
Will it work as the bike is a k75 3 cylinders?
Thanks

    

Suzi Q

Suzi Q
Life time member
Life time member
Not sure which particular chinese gauge you have, but the ones I've used on K75 engines work fine if you leave the setting as 1 cylinder - I guess this is because each cylinder on a triple has its own coil, just like a single.

I remember when I was googling around to try and figure out my own 'chinese gauge', there was more than one mention that once you programmed the gauge for 2 or 4 cylinders, there was no way to program it back to 1 cylinder. Not sure how correct this is, just mentioning it FYI.

Robmack - how does the capacitor/resistor that you describe produce a signal that swings around ground - just interested, I'm an electrical dummy?


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

charlie99

charlie99
VIP
VIP
the resistor will tie the output signal towards ground, the capacitor will let the change in voltage pass not the dc component so it should have a swing above and below ground (= 0 volts )?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

robmack

robmack
Life time member
Life time member
What I'm describing is a R-C differentiator circuit.  It looks like this:

K100 rs16v - BEP3 - Acewell 4453 Rc-rc13

The Differentiator is a High Pass Filter type of circuit that can convert a square wave input signal into high frequency spikes at its output.  When the capacitor is fully charged the output voltage across the resistor is zero. The arrival of the falling edge of the input waveform causes the capacitor to reverse charge giving a negative output spike, then as the square wave input changes during each cycle the output spike changes from a positive value to a negative value.

In the diagram above, the square wave is the BEP output appearing on its RPM pin.  The output of the circuit goes to the tach input on the cheap Chinese gauge.

Program the gauge to read 1 pulse per revolution.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Suzi Q

Suzi Q
Life time member
Life time member
Much appreciated - it just hadn't occurred to me that the trailing edge of a positive-going square wave would produce a negative voltage after a capacitor. I guess that's because with these filter/conditioning circuits we've previously always been doing the opposite - taking a messy spike from the coil or speedo sensor and smartening it up for the gauge.

Thanks for the 'change in voltage' tip Charlie - explains it clearly.


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

Salim

Salim
New member
New member
I will try it this weekend

    

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