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How To BMW R18 K34 Factory Tachometer Build

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JAMUSAURUS

JAMUSAURUS

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Joined
Aug 1, 2023
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190
Location
Toronto, Canada
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Bike
BMW R18 100 Year Edition
Intro:

I started this journey asking questions on the forum back in 2023. I am finally proud this project is finished and I wanted to share it with you all incase you want to do the same thing. I'm one of those individuals who use their tachometer and was bummed out when this wasn't a factory option on the R18. I quickly got annoyed having to flip through the menus for the time, tach, and distance driven as I use those features consistently while I'm on my rides. Looking to the aftermarket options, I disliked what's available as it didn't look factory. This should have been available as a factory option.

Additionally, I've also confirmed the fuel gauge also does work for anyone wanting to add to their build.

BMW Part numbers are at the bottom of the post. The history thread is linked here for anyone wondering.

IMG_5774.jpegIMG_5779.jpeg

Wiring
*Pinout of 4 Wires from ECU Harness to Speedometer:
  1. Yellow = ACC signal for power on/ backlight
  2. Brown = Ground
  3. Red/Green = 12V + Linbus data for engine information
  4. Grey/Purple = likely related to accessory communication.
Connections needed to mate the harnesses are really only 3 wires. The gauges are 'smart' and operate by listening to the specific data from the ECU through the Linbus system (which is transmitted from the Red/Green wire). Match the wire colors with the only difference being the Red/Blue wire. This same set up will work for the fuel gauge as all the gauges operate off the same circuit.
Quick reference below:
Yellow -->Yellow
Brown --> Brown
Red/Green --> Red /Blue
Click to expand...
Back of Tach Connector, K35 Harness
**Back of Speedo connector**

The catch here is you will need a donor cable from the K35 Bagger/ Transcontinental as BMW doesn't sell these cables/connectors separately to make your own harness. The work is simple as it just requires splicing the matching wires together from the donor harness to the main cable on the bike that powers the Speedo (or any other gauges you want to add in series). Up to you on how to connect them (solder direct/ run a connector inline), however, I chose to use a Deutsch 4 pin connector (DTM04-4P & DTM06-4S) so I can quick disconnect them or modify if needed in the future.

**Picture of the donor wiring harness I used to make my new harness**
IMG_3323.jpegIMG_3322.jpeg


Mounting:

I simply welded the factory R18 bracket to the the R9T factory bracket which I ordered from my dealer. I outsourced the powder coating to a local shop.

Before:
IMG_5701.jpegIMG_5702.jpeg

After (Cutting, Welding, Powder Coating)
IMG_5767.jpegIMG_5768.jpeg

After everything was fabricated, it all bolted together perfectly.

BMW Motorrad Parts Used:

62119446548 - K35 Bagger Tachometer
77538389483 - NineT Gauge holder mount
62119480185 - Cluster housing (Black) (#3)
62119467601 - Inner Plastic Spacer (#2)
62111539597 - Housing Trim Ring (Chrome) (#7)
64226916475 - Countersunk Head Screw (you will need 1 of these) (#4)
62118356970 - Rubber Grommet (you will need 2 of these) (#5)
46638521655 - Body screw with collar. M5X20 (#6)
11107811 - K35 Wiring Harness (unsure if BMW sells directly)

Assembly.png
 
Last edited:
JAMUSAURUS said:
This is how the R18 should have come from the factory
Click to expand...
No.

When viewed from the rider position on the bike, the R18 from the factory is an excellent modern visual take of the original single head. The later roctane took it up a notch in that regard.

IMG_1963.jpeg

But very, very nice work and write up. Thanks for sharing.
 
Last edited:
JAMUSAURUS said:
Nah, this has it's own look and honestly, this looks way nicer than the Wunderlich factory positioning. Thanks for sharing, Ulrich!
Click to expand...
Actually this is Wunderlich ... I had a friend pick me one up in Germany and send it to me couple years back ... I was going to make my own bracket ... but it seems there is a difference between the German model and the US one ... I was told that the US version does not work with the OEM windshield ... it seems the German version does ... works for me ;)
 
That’s a lovely job, feast for the eyes, only spoilt by the mobile phone carbuncle (should be banned ugly things)….

IMG_2551.jpeg
 
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