The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: plc on June 09, 2009, 06:31:14 PM

Title: Tacho pickup on pin7?
Post by: plc on June 09, 2009, 06:31:14 PM

Hi All,

When diagnosing my faulty ignition can I also disconnected my ICU to put new thermal grease on the heatsink. I noticed that my pin 7 is not connected. Many things I read say pin 7 is the tacho pickup. Yet according to my bike (as wired which may have been modified), and the Clymer manual there are only 6 wires to the ICU. On top of that three of the six wires connect to a three wire switch block and the other three goes to the trigger.

So my question, have any of you found pin 7 connected on your R65? If so how does it connect to the tacho? If no where does the tacho get it's signal from? The Clymer manual doesn't show anything other than a positive wire.

Best to all,
paul

Title: Re: Tacho pickup on pin7?
Post by: montmil on June 09, 2009, 08:09:00 PM

I'm away from my tech info but I do recall that one of the terminals on the ICU is unused. Which numbered terminal... ?

Title: Re: Tacho pickup on pin7?
Post by: Bob_Roller on June 09, 2009, 11:05:26 PM

Pin 7 is the tachometer output signal from the ICU .

I got this off of Euro Motoelectrics website :

Pin 1 - coil output
Pin 2 - B-  hall effect sensor
Pin 3 - B-  hall effect sensor
Pin 4 - B+ hall effect sensor  power from ICU
Pin 5 - + input  12 vdc from bikes electrical system
Pin 6 - - input  ground or negative from the bikes electrical system
Pin 7 - tach output signal

I don't have a wiring diagram handy, but pins 2 and 3 , one is a ground for the hall effect  circuit, and one is the hall effect sensor output signal .

If by chance this info is wrong, the tachometer may get it's signal from the coil output, the wire may split off someplace .

Title: Re: Tacho pickup on pin7?
Post by: steve hawkins on June 10, 2009, 03:13:29 AM

My tacho input comes from the coil but I have have a pre-81 R65.  

Title: Re: Tacho pickup on pin7?
Post by: Bob_Roller on June 19, 2009, 07:36:20 PM

I just checked the owners manual that I got with my LS yesterday, and the tachometer signal comes off of the ignition coil .

I can't read which pin it is on the ignition control module, but it's the only black wire at the connector for the module .

Title: Re: Tacho pickup on pin7?
Post by: plc on July 02, 2009, 09:21:34 PM

Thanks Bob, it confirms the wiring diagram in my owners manual that i just found.  My diagram shows the module has one unconnected pin which confirms the physical connection on my bike.

It appears that it is erroneous to say that the tacho signal comes from pin 7 on our R65s.

Best to all,
Paul

Title: Re: Tacho pickup on pin7?
Post by: Bob_Roller on July 02, 2009, 09:28:08 PM

That pin number 7 may be a tachometer output, as this electronic module was or is in common use in European 4 wheelers of the same time frame, but BMW decided to take the signal right from the ignition coil instead .