This page last updated Nov 10, 2008

Component typeQuantityComponents
470R 1/4W 5%1R11
1k5 1/4W 5%2R26, R27
2k2 1/4W 5%1R34
2k7 1/4W 5%1R25
3k3 1/4W 5%1R35
3k9 1/4W 5%3R28, R29, R29b
6k8 1/4W 5%2R31, R31b
47k 1/4W 5%16R5-8, R12-16, R12b, R22, R23, R32, R33, R32b, R33b, R36
10k 1/4W 5%13All other resistors
27pF2C1, C2
10nF (103)2C11, C11b
1uF (105)2C12, C12b
6u8F 35V1C18
22uF 16V1C17
100nF (104)14All other caps
100uH2L2, L2b
IN40033D1,D2, D4
IN58191D17 Schottky diode
IN91418All other diodes
8Mhz crystal1X1

Click on the board layout below to open up a large window ECU PCB diagram

Here are some photos of the MyP8 -
Left hand side (500K) Underside (500K) Right hand side (500K)

Component typeQuantityComponents
40 pin IC socket1U1
8 pin IC socket1U2
4 way switch1SW1
5 pin header1Conn3
3 pin header1Conn4
3mm nut/bolt2
I suggest the following order for assembly and testing.

Hint - cut leads from solder components can be used for some of the the links.

Initial Assembly

  1. Start with the RS232 adapter board.
  2. Remove the original circuit board from its case. The mounting screws and the transistor mounting hardware WILL be used for MyP8. Do not remove the ECU connector yet.
  3. Make sure the MyP8 PCB will fit in the case. Some trimming of the edges or mounting holes may be required.
  4. Check all the PCB holes are clear. A soldering iron should quickly clear any solder.
  5. Check the holes for mounting Q3 and Q4 and the RJ45. These may need to be drilled out ( 3mm ).
Start with the 16 47K resistors.MyP8 as shipped Then install the 13 10K resistors. I missed R24 at the bottom :-). With the cutoff resistor leads, apply the 8 links required. I've not shown this.MyP8 ass2
Solder the 18 small signal diodes. Orientation is important. D17 is now IN5819.MyP8 ass3 Install the 14 104 capacitors and the 2 IC sockets.MyP8 ass4
Solder the 2 1.5Kresistors (near top), the 2 6K8 resistors ( central ) and the two resistors inside the 40 pin socket.MyP8 ass5 Install the 2 105 capacitors and the 3 3k9 resistors and the general purpose diode and the BD139 transistor. MyP8 ass6
Solder the 2 100uH inductors, the general purpose diode, the 2N7000, the 20V zener and the 470ohm resistor. R10 is now Polyswitch.MyP8 ass7 Install the BD140 transistor. On some early PCBs, the centre pin was erroneously left unconnected. It should be soldered to the earth track. Leave space for the screw.MyP8 ass8
Install the 2 103 capacitorsMyP8 ass9 Install the 4 BC547 transistorsMyP8 ass10
Install the 2 electrolitic (used to be tantalum) capacitors - orientation important.Install the crystal and the 2 ceramic capacitors.Install the 5 and 3 pin headers. The switches should be set to On, Off, Off, Off.MyP8 ass11 Install the RJ45.MyP8 ass12

Testing and further assembly

A 9V battery and a multimeter will required for the following tests. Solder the 9V battery leads to where the ECU connector will go. The positive lead will go to pin 20. The negative to pin 1. Do not proceed past a test step unless it is successful.

  1. Connect the battery and check that R10 is not getting warm.Disconnect the battery if it is.
  2. Now check the voltage across R10.It should be less than 1/4V as no current should be going through it.
  3. Disconnect the battery. Now we will add the voltage regulator. Insert the component into the PCB but do not solder. You need to place the PCB into the ECU case. The regulator does not need to be insulated and can touch the metal. Determine the required position of the regulator and then solder it in. Perform the first 2 test again.
  4. Place the negative lead of the multimeter on the right leg of ZD1. This will be our zero volt reference for all further measurements.
  5. With the positive lead of the multimeter, check for 5V +/- 5% on the lower leg of D4, the upper leg of R34, the upper leg of R33,the upper leg of D11. A failure here is probably a link not installed.
  6. Check for close to 9V the link above T7.
  7. Check for 2.5V on the lower leg of R32 and the upper leg of R32b.
  8. Check for 3.0V on the upper leg of R35.
  9. Disconnect the battery and install all the transistors. Q1 and Q2 will have to be sized up against the case. They will require insulation from the metal.
  10. Make sure all 4 switches are off ( open circuit )
  11. Lastly insert U1 and U2. Make sure they go the correct way and don't bend pins.
  12. Apply power again. Look for U1 pin 26 going near 5V for about 2 seconds and then returning to 0V. This is the fuel pump output
  13. U2 pin 5 should be at about 3V
  14. U1 pin 22 and pin 23 should both be near 5V
  15. U1 pin 24 and pin 25 should both be near 0V
  16. The gate of Q3 ( closest to Q4 ) should be near 0V
  17. The gate of Q4 should be near 0V
  18. The gate of Q2 should be near battery voltage.
  19. The gate of Q1 should be near battery voltage.
  20. Disconnect power. Solder a wire from central pin of Q5 to pin 21 of U1. Apply power and check that right leg of D17 is now above battery voltage.
  21. Disconnect power. Connect the ECU to the RS232 adapter board using the RJ45 connector. Connect the adapter into the Comm1 port of your computer. Start up the ECUController program.Apply power. The ECUController should start receiving the ECU data.
  22. Disconnect power. Solder on the ECU connector and fit into the case. Remember Q1 and Q2 MUST be insulated from case.Do not add top or bottom of case yet.


If you still have a functioning OEM ECU. Start the bike with this and thoroughly warm up the bike. Fit the MyECU to the bike ensuring that the exposed insides will not short against bike or battery even with the vibration of the engine. We will turn the ignition on for 3 seconds ONLY. You should have hear the fuel pump energised for 2 seconds. Quickly check that none of the power transistors are warm. If all is OK we can attempt to start the bike. The bike may require some throttle to maintain operation and may run roughly but this is to be expected at this stage. We just need to verify that the engine is running on all cylinders.

RS232 Adapter board

C1 - 100uF
C2-5 - 1uF
U1 - MAX2320

The electrolytic capacitor is polarised and must be inserted the correct way.0