Assembly Instructions

Selettra racing ignition assembly instructions

Install the ignition coil properly with the core lamination package (bracket), ideally hanging on the vehicle frame, see Fastening the ignition coil. The electronics are protected against vehicle vibrations and shocks by silent blocks.

Establish a good ground connection between the engine block and the vehicle frame using a ground line with at least 4mm².

Silent blocks must be bridged with a separate ground line, otherwise the electronics will be destroyed in a few seconds.

Never apply a bending moment to the ignition coil holder. NO GUARANTEE!

Fasten the stator using the three elongated holes in the motor housing. For vehicles in which a Selettra racing ignition is retrofitted, a specially made adapter plate may be necessary (non-magnetic material, if possible non-conductive to keep the engine heat away from the stator).

The rotor is placed on the crankshaft side journal. Impurities must be removed beforehand, the crankshaft stub and inner rotor cone must be free of grease.

It is important to ensure that the rotor is seated firmly; it may be necessary to lap the rotor onto the side journal with a grinding paste.

The position of the crankshaft, rotor and stator must be observed, see “Setting the ignition”.

Connect all the necessary ground lines for the ignition.

Connect the stator connector to the ignition coil. Connect the ignition switch and, for ignitions with 2 ignition curves, connect the ignition curve selector switch.

A breakaway switch is often used as a safety switch in racing, and can also be used as a changeover switch for the second programmed ignition curve.

Function of the tear-off switch (quick stop, emergency stop):

If the connection line is connected to ground, the ignition is switched off. If it is not connected, the ignition is ready for use.

For ignitions with 2 ignition curves, the 2nd ignition curve is activated when the connection cable is connected to ground. If the line is not connected, the 1st ignition curve is active.

With Selettra ignitions, you can switch between the ignition curves during operation.

A radio interference suppressed spark plug connector with 5 kOhm is recommended for digital ignition systems!

Alternatively, radio interference suppressed spark plugs can be used, these items are available in our Dmon-Parts Shop.

Screw the spark plug connector into the ignition cable and plug the spark plug connector onto the built-in spark plug.

Example calculations from timing calculation V1.1 (Christoph Köhler):

Engine type Degrees crank angle before TDC Piston position in mm before TDC

500cc Motor cycle 10° 0.8 mm

Stroke 86 mm 20° 3.2 mm

Connecting rod length 160 mm 30° 7.2 mm

250cc Motor cycle 10° 0.5 mm

Stroke 68 mm 20° 2.7 mm

Connecting rod length 130 mm 30° 5.6 mm

125cc Motor cycle 10° 0.5 mm

Stroke 54 mm 20° 2.0 mm

Connecting rod length 110 mm 30° 4.4 mm

50cc Moped 10° 0.4 mm

Stroke 44 mm 20° 1.6 mm

Connecting rod length 85 mm 30° 3.6 mm

50cc Scooter 10° 0.4 mm

Stroke 40 mm 20° 1.5 mm

Connecting rod length 80 mm 30° 3.3 mm

Sample information without guarantee!

For flashing off the Selettra ignition, we recommend the stroboscopic flash lamp from Bosch with the number 0 684 100 309 – 424