CDI unit bad wiring

I was given a yamaha cv80 and the whole thing was in very bad shape. I started rebuilding and have gotten things almost to a running point but, the wiring was shot it had been rewired at least once before. The wire harness was almost destroyed, So I started to rebuild I have checked the magneto and it seems ok, the coil was damaged so I put a new one but the cdi was blown. I have attempted to rebuild it too, I cut the black box off and used an exacto knife to remove the thick black rubber off of the circuit board. I am strapped for cash so I am doing this the hard way. My problem is and I have researched magneto systems a lot I have books on motorcycle and moped repiar but I still have no spark. Now the cdi in this moped is not like the one in the circuit diagrams, it uses a Thyristor to kink up a certain amount of voltage and then the discharge coil signals to the thyristor to release it's voltage. This then goes to the coil causing a spark. Or so at least from I can figure out. I had a bad diode on the board and a bad Thyristor and replaced them but still no spark. I could use some very technical help on this. I was even thinking about maybe building a new cdi unit from scratch using the standard diode, capacitor, and zener diode circuit. Thanks for all the help in advance.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account