No need to bet, Mighty LynnEdwards. Right after I posted my last post, I discovered that the two ground pins are connected!

 

Mighty LynnEdwards, when I connected this CDI, it made a high pitched whine. Is that normal?

 

I've never looked at a performance CDI. But it is possible that is is normal. I don't know.

All CDI output sections internally run on moderately high voltage DC (300 volts or so). On an AC powered CDI this moderately high voltage is derived by simply rectifying the moderately high voltage coming off the AC ignition power winding of the stator. On 12 volt DC powered CDIs the 300 volt or so internal supply must be generated with a switch mode power supply. This circuit takes the 12 volts DC and turns it into AC by switching it on and off very rapidly. A transformer or inductor is used to step the voltage up to a few hundred volts, where it is rectified back into DC.

I would doubt that any supply today would be switching the 12 volts DC on and off in the audio range (which would definately make audible noise). Instead they would be switching in the hundreds to thousands of kilohertz. But if your CDI is being powered up but not being triggered there is no power being used at the output. So the power supply bring up the internal voltage to 300 volts and then shuts down. The voltage bleeds down relatively slowly (compared to 100 microseconds), and then at some point fires back up and recharges the internal suply again. You might be just listening to the supply shutting down, wait..., and starting back up. And so on....

I wouldn't worry about that audible noise as long as it produces spark when the engine cranks.

 

Ok to get power to the CDI, should I run 8 gauge wire from battery to stuff(maybe to big) and 10G wire from stator to regulator then 16G wire to wire harness?

 

Also, should the ignition switch power the CDI and other stuff or should I use a solenoid?

 

The starter motor wiring from the positive battery terminal (through the solenoid), and its return path back (starter motor case to the negative battery terminal) needs to be heavy gauge. Everything else is fed though a fuse located right at the positive battery terminal. All the wires fed through this fuse should be able to safely handle the current the fuse allows.

16 AWG is fine with a 10 amp fuse. This gauge wire can fed everything (other than the high current starter motor stuff) which includes the stator, regulator, ignition switch, CDI, lighting, starter solenoid input wires (the small ones).

The CDI is powered off the output side of the ignition switch.

 

What if the ignition switch is an el cheapo and do you think that a "magneto ingnition switch" is going to work? I am concerned about the connection in the ignition switch...

 

It needs to be a switch rated to for 10 amps. There is nothing else special about it. I don't know what an "el cheapo magneto ignition switch" is... Is it good for ten amps?

Have you planned on where you are going to wire in the regulator output? This is the output wire from the regulator that charges the battery. There are two basic methods: Wire it directly to the *fused* 12 volts from the battery (before the ignition switch), or wire it to the *switched, fused* 12 volts (after the ignition switch). If you wire if after the ignition switch then you'll need a kill switch of some sort too. This is because the power to the CDI won't go away when you turn the ignition switch off - since the regulator will take over and keep the 12 volt bus powered up even though the ignition switch is off.

 

I will probably wire directly to battery. Also, what kind of fuse should I use? Ok another question, how is the ignition coil connected? Isn't ground to green and black connects to the wire on CDI?

 

Any in line automotive fuse will work. You can use the blade type (like in most cars now), or the 3AG type (glass cylinder anout 1/4 inch diameter and about 1 inch long). Also, if the fuse says 125 VAC or some other voltage rating that is OK. That's the maximum voltage it can safely interrupt. 12 volts is lower than that so it will be fine.

Usually the ignition coil is grounded by the mounting bolt. But sometimes there is also a ground wire too. Am I correct in assuming there are two wires at the ignition coil (ignoring the fat high tension lead to the spark plug)? If so measure the resistance of both those wires to the coil mounting bolt. One will read zero ohms, the other will read a low value like 0.7 ohms (but not zero). The low value terminal is the one that wires to the CDI ignition output. The zero ohm terminal goes to ground.