Tachometer & gear indicator for the KTM 640 LC4

Display

The display was mounted centrally on the 22 mm handlebar using a display mount.

Power supply

I separated the 11 wires of the KTM's standard connector and soldered them to 2 mm gold-plated connectors. That's not strictly necessary for the Cumpan, but I plan to fit a different speedometer later and would have had to do it anyway. I tapped positive power (a permanent positive isn't necessary) and negative from the original speedometer's wiring, just like the cable for the km/h speed input.

Engine temperature 1

Temperature sensor for the oil temperature gauge.

Sensor used: M8×1,25

For the engine temperature connection I installed the M8 x 1.25 sensor from Berotec. On the LC4 with the High Flow engine, the suitable spot seemed to be the crankshaft positioning bolt at the front of the engine. Installation was fairly easy — I only had to unscrew the oil filter guard. However, the temperature seems too low to me; I'd be grateful for other people's experience here.

RPM

Tapping the RPM signal for the tachometer.

The LC4 doesn't have a rev counter as standard. However, I was able to tap the RPM signal for the Cumpan's cable fairly easily from the ignition coil using a branch connector. To do this, the tank shrouds had to be removed and the tank lifted.

Engine temperature 2

Temperature sensor for the water temperature gauge.

Sensor used: Water temperature sensor with adapter - 18mm

The LC4 has a water temperature display as standard, which is fed via a connector at the cylinder head. My hope was to also supply the Cumpan via this line into IN 1. Unfortunately that didn't work — I started the engine at 112 degrees and the reading kept getting colder. KTM and Berotec apparently use different characteristic curves here, so no adjustment was possible. I therefore ordered the 18 mm water temperature sensor from Berotec. The right-hand tank shroud had to be removed. I then cut the hose between the engine case and the radiator in the middle and shortened it using a cheap Parkside pipe cutter. The sensor still needs to be connected to power.

Gear

Gear detection for the gear indicator.

I'd like to use the gear indicator together with the km/h and RPM function. The settings for the KTM have to be entered separately — the CAR and BIKE presets are of no use here. For that, UNI has to be selected under SENS. I set the wheel circumference for the Supermoto to 1890 mm, the ignition pulses to 1, the number of gears to 5, and the number of bolts on the brake disc to 6. By the way, the bolts aren't magnetic. Without a gear position sensor, iGEAR then has to be selected. Then, under CALIBRATE, ride for 180 seconds and shift through all gears.

Speed (reed sensor)

Reed sensor on the wheel for the speedometer.

The reed sensor has three wires that connect to the speedometer: blue-yellow is the positive ignition wire, black-brown is the negative wire, and black-orange is the signal wire. Connect the orange-black cable from the KTM to the Cumpan’s speed sensor and make the settings I described under “Gear Indicator.” The Cumpan is the only aftermarket speedometer I was able to operate with the original sensor. Daytona and Koso didn’t work, but I’d be happy to be proven wrong here.