Honda CBR Tooth Eater Module - Compatibility module for the CBR 1100XX Super Blackbird and other CBR models using the CBR trigger pattern.

This Tooth Eater module is a small electronic box designed to work with the Honda CBR family of motorcycles that use a 3T cam trigger and 12T crank trigger (mainly earlier 2000's models).

Some examples are:

- Honda Blackbird CBR1100XX

- Honda ST1300

- Honda CBR600F4I

- Honda CBR919

- Honda CBR929

- Honda CBR954

- Honda CBR1000RR

- Honda Aquatrax jet ski

and perhaps some other models that fit this criteria. To date, only the Blackbird has been tried with success (my bike), however there is no reason it should not work on the above mentioned CBR models since they all use the identical trigger system.

It is aimed at the user who would like to install a stand alone ECU system of their choice on their motorcycle whereby the ECU does not support the Honda CBR trigger pattern natively. This small module translates the Honda's CBR peculiar 3T camshaft trigger wheel pattern into a universal single trigger pattern (I.e. 12T crank + 1T cam). This makes it compatible with most after market ECU systems such as rusefi, speeduino, etc.

It works by digitally deleting (eating) two cam trigger pulses, allowing the remaining pulse to pass through. This single cam pulse can then be configured as 'home' position on a standalone ECU system. This is a very standard configuration that most (if not all) aftermarket systems support, allowing you freedom of choice when choosing an aftermarket ECU system.

A benefit of this tooth eater module is that it makes it unnecessary to have to modify the bikes trigger system. In the past, others have had to physically remove the cam spokes from the trigger wheel (I.e. By hack-saw or grinding off teeth) to install a standalone ECU. This module allows you to leave everything physically intact. You only need to deal with the electrical side of things. Another side benefit of this is that it also allows you to easily revert to the OEM ECU if you wish, provided the original wiring harness and ECU connectors have not been disturbed.

This module also converts the raw VR signals as produced by the motorcycles cam and crank inductive sensors into 0-5v TTL level signals that can be directly fed into a standalone ECU. To achieve this, the tooth eater module has made provision for (and makes use of) the speeduino VR plug-in module that is inserted into the board. This can be seen in the picture below. These VR units can be purchased online and various designs are also available here on PCBWay. This way, you configure your ECU as if they were from a HALL sensor, since the signals are already TTL.

Note: To date, I have only tried the NCV1124 chip on my motorcycle with success. I have not tried the MAX9926 as yet, although I'm confident it will also work.

The tooth eater module also houses a small ATtiny85 microcontroller that is running the firmware to delete (eat) the incoming teeth. The ATtiny85 will require programming using a sparkfun programmer or similar since a '.hex' will need to be burnt into it. There is no bootloader involved.

The tooth eater must reliably sync to the intended cam tooth on every engine start. Once your ECU trigger settings have been configured with the correct 12/0T crank / 1T cam, you will then simply adjust your global offset trigger angle with a timing light to lock onto TDC for cylinder #1 with fixed ignition timing.

Below is a screenshot as the engine running and what can be expected on the trigger scope in Tuner Studio from the output of the Tooth Eater module. I.e. 24 crank pulses per engine cycle (720 deg being two crank revolutions) whilst producing exactly one cam pulse.

This device is quite simple in its operation. Once it determines the initial sync, it behaves as a simple counter from there on. As such, it is important to configure your ECU to manage its cam SYNC internally and not rely on the tooth eater module when the engine is running.

The unit is powered by the bikes 12v supply (same supply wire that powers the ECU).

The inputs to this module are:

-> CRANK VR+ (from the bikes wiring harness)

-> CAM VR+ (from the bikes wiring harness)

-> VR- (shared on the bikes wiring harness)

The outputs are:

-> CAM TTL (0-5v). A single cam pulse per engine cycle that is fed into your downstream ECU.

-> CRANK TTL (0-5v). A constant stream of pulses, 12 per crank revolution, 24 per engine cycle. This is a pass through signal from the VR that is fed into your downstream ECU.

-> Tacho output (0-12v).

This tooth eater module is intended for the electronics DIY'er that has knowledge in configuring ECU systems on engines. It has been designed as a 'through-hole' version for easy assembly. It is possible that in the future that I will also design a SMD version for more integrated setups.

Full details of this project can be found here under the various repositories:

Main page:

https://github.com/blackbirdstandalone

This project:

https://github.com/BlackbirdStandalone/ToothEater-HW-THT

Firmware:

https://github.com/BlackbirdStandalone/ToothEater-Firmware

Adapter Boards:

https://github.com/BlackbirdStandalone/AdapterBoard

Additional videos are available if 'blackbird standalone' is searched in vimeo.

Note: This hardware component of this project is licensed under the 'CERN Open Hardware Licence Version 2 - Strongly Reciprocal' (CERN-OHL-S)