BMW K bikes (Bricks)

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Oliverinlux

Oliverinlux
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Hello as I said I just put on my aftermarket koso speedo on my 94 k75 and all is well thanks to a conditioning circuit made by a friend for the speedo and sans the fuel gauge as the k bikes resistance is strange when it comes to the fuel gauge. (something I also need help with by the way)

HOwever the tachometer seems to be reading different to what the motometer was. normally 73 mph equals fifth gear at 5000 rpm on the original motometer however on the new koso unit it reads that when I feel the bike at top comfortable speed (normally around 73mph at 5000rpm) the new speedo says i am only at around 4300rpm so it is not a gigantic difference but definitely noticeable. So maybe the original motometer is wrong (which is most likely true, however Ive heard of the OEM speedometer being incorrect but never heard word of the tach being off) or the new KOSO meter is reading incorrectly. Any ideas?

ALso does anyone know a way I can use the original fuel level sender on the new koso? The koso has two different settings for the fuel gauge at either 100 ohms or 510 ohms but IM guessing these all run opposite to bmws fuel sensor.

    

RicK G

RicK G
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The original speed/rpm readings are correct.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

rosskko

rosskko
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Is it possible to use the KARAMBA software to test the speedo or is that purely for the original?

Maybe the soldering iron to the rear sensor or is that gone too in favour of a front wheel sensor?


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

charlie99

charlie99
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could it possibly be that the pickup for the tacho is in someway different to what the new unit requires

some of these devices come with a pickup sensor "in the kit " usually a pickup of the high tension side of the ignition system

just throwing that in the ring


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OJust connected AM koso speedo to k75, tach not reading correct or is it? Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

robmack

robmack
Life time member
Life time member
@Oliverinlux wrote:ALso does anyone know a way I can use the original fuel level sender on the new koso? The koso has two different settings for the fuel gauge at either 100 ohms or 510 ohms but IM guessing these all run opposite to bmws fuel sensor.
Short answer:  I don't believe it's possible.

The koso, like other aftermarket instrument clusters, expects the fuel sender input to follow the Jap bike standard of a high resistance when the tank is full, and low when empty (see https://www.k100-forum.com/t3349-testing-in-tank-fuel-sender-unit#76423 ).  The BMW sender is opposite to this.  It would be simple to convert the fuel sender's variable resistance to a variable voltage, but there's no way for the Koso to process this input.

If you feel brave, it might be possible to open up the fuel sender and change the wiring inside.  But be prepared to buy a new one if this fails.



Last edited by robmack on Mon Jan 06, 2014 11:50 pm; edited 2 times in total


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

RicK G

RicK G
admin
admin
An easy way to correct the tach or speedo readings are the speedo healer from healtech. They have lots of wonderful stuff.
http://www.healtech-electronics.com/


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

Oliverinlux

Oliverinlux
active member
active member
Thank you all for your input.

I have a conditioning circuit for the speed sensor and it works fantastic so I am not using a front wheel sensor I am using the stock final drive speed sensor connection for my speedo.

I have set the Koso speedo to pick up the hi input rather than low (with the low I wasnt getting a reading at all) It did come with a few different connectors for different ways to pick up the revs but seeing as the Black/blue wire going to the original speedo came straight from the ignition coil I just used that wire instead. 

Thank you very much for the info on the KARAMBA program Im guessing that will be the only way I can find out for sure if my new speedo is getting the correct reading and the old tachometer was actually off or if the new one is missing some pulses.
Just want to reiterate I am trying to find what my bikes actual rpms are not the mph

About the fuel sender than kyou I will look into that post and seeif there is a way to reverse the resistance in the fuel sender. Maybe that post has the info, I will be reading it soon but Im wondering if there is a simple converting circuit I can put between the fuel sender and the KOSO unit to reverse the resistance and turn it into a resistance that can be read by the koso.

thanks again for all the input

    

8Back to top Go down   Just connected AM koso speedo to k75, tach not reading correct or is it? Empty alsoo^^^^^^ Tue Jan 07, 2014 4:13 pm

Oliverinlux

Oliverinlux
active member
active member
Im wondering if maybe i could find a cheap honda fuel sender off ebay and put that in the tank to replace the original. guessing that would take a little fabrication but thats nothing the old torch and bridgeport cant handle. ANy thoughts?

    

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