Reply To: CDI teardown and repair
Hmmm, doesn’t seem to like me!! Oh well, a brief update then instead.
Firstly these igniters on the GV650 are described as CDI’s. They are NOT! As I found out from my tear down.
They are actually transister controlled igniters (TCI) and work just like the old engines that have distributer, points and condenser, except it’s done electronically by a thyristor switching the 12v supply to the ignition coils to ground causing the electromagnet field to collapse across the secondary windings of the coil which in turn creates a spark at the plug. It is a wasted spark configuration for simplicity.
As a tip to others reading this, if you are unsure whether you have TCI or CDI unit a simple confirmation check is to turn on the ignition and use a tester/multimeter between the ignition coil positive terminal and ground. If you have battery voltage (c12V) it’s a TCI if you have no voltage it’s a CDI.
The Kokusan Denki BB7725-1 fitted to the GV650 Carby looks to be multi use with its 16 connecting pins and the same unit is used on the GT650 Carby but utilising some different pins as can be seen when comparing both wiring diagrams. This was done probably as a cost saving design. The pcb uses surface mount technology rather than through the board so replacing components is much more tricky.
I’m thinking at the moment to build my own TCI and have priced up components which amount to c45 euros plus the price of a decent project box to mount it in. The main component would be a Arduino Nano microcontroller which is programmable to ensure correct auto advance of the ignition and dwell adjustment.
The alternative would be to buy a new programmable unit for c200 euros.
I’ll sleep on it for now!!