MY ALBUM 3.4.5
Transistor Ignition
A simple electric ignition for two cylinder motors. My main interest is in my MotoGuzzi V65C with a 90deg V2. I had a Piranha ignition, but there was troubles, so I designed my own. The original system has two mechanical breaker points and Piranha has two optos. My system has only one opto.
The idea behind this system is that another cylinder ignites on the rising edge of the chopper and the other cyl on the falling edge. It is easier to make the optical chopper plate 135 deg than set two optos 135 deg apart each other. I buil an temporary axel of nylon, which I fixed to the bottom plate of the system. I fixed a 100 mm long wire to the chopper and draw two marks 135 deg apart of each other on a piece of paper. For the indication I connected a LED to the system. Then I slowly rotated the chopper until the LED went OFF and set the mark zero on the paper under the wire pointer. Then I continued rotating until the LED went ON. Then I filed the chopper a bit and continued rotations until the arch was exactly 135 deg.

If you use a 7406 OC TTL hex inverter, you got two spare ports. You can use them to drive two LED. This makes it easier to set the initial 7 deg (in V65C) advance.

The coil ignites when the current from coil pin 1 to ground is CUT.

Compared to the old system (Piranha):
- More powerfull spark !!
- Starts easier
- Eats less
- Runs better with no odd sounds or wibrations
- Accelerates better.

080310 A simple uP based advance system under work.
Here is a good page about advance (Fi) http://www.torinoproject.com/tech/ignition.htm.
At the same gas mixture it takes the same time for the flame to reach the edge of the cylinder. So the advance in seconds should be the same.

Addendun 120714: I found that there is also a 4-channel ignition module BOSCH 0227100211, which can be used. Check here in directory Collected

Dual ignition module: You can use the Bosh ignition module 0227100200 or 0227100204. BMW 12141461441, OPEL 90449574, PORSCHE 99360270600 0227100200 can be found in Fiat Punto GTI, Fiat Ulysse 2.0 Turbo. BMW k1, k100, K1100