Need a CDI...

PhoobarID

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Took the 66cc out for it's virgin ride Monday afternoon. Made it about 9 miles with bugs in my teeth & wouldn't run at all. After pedaling it about 1/2 mile home...took out the plug & found I was getting no spark. Think my buddy wired up the kill switch to the CDI wrong...so it was fried.

If anyone's got a good used CDI with the steps on wiring it up correctly & want to get rid of it for about $5 or so (new ones with shipping run about $25 & I just don't have that kind of money right now)..let me know in PM.

Thanx...
 
Took the 66cc out for it's virgin ride Monday afternoon. Made it about 9 miles with bugs in my teeth & wouldn't run at all. After pedaling it about 1/2 mile home...took out the plug & found I was getting no spark. Think my buddy wired up the kill switch to the CDI wrong...so it was fried.

If anyone's got a good used CDI with the steps on wiring it up correctly & want to get rid of it for about $5 or so (new ones with shipping run about $25 & I just don't have that kind of money right now)..let me know in PM.

Thanx...

Before you invest in a CDI, check the voltage that the magneto is putting out if any. If you don't have a test light/volt meter I can tell you how to make a easy and CHEAP test light. 1 bulb and a few feet of thin wire, solder or tape.
 
gasbikes.com has CDI's for $10.
Did you check the 2 wire connections from the CDI to the motor?
One coming loose is very common.
Also, just disconnect the kill button from the white magneto motor wire in case it is shorting.
 
Before you invest in a CDI, check the voltage that the magneto is putting out if any. If you don't have a test light/volt meter I can tell you how to make a easy and CHEAP test light. 1 bulb and a few feet of thin wire, solder or tape.

How do I actually test it without being able to get the bike started? What readings are there supposed to be & in what range if someone has a meter?
 
gasbikes.com has CDI's for $10.

Looked at that source first. The bad thing about them is their cheap prices...but high shipping costs. That costs as much or more than the part itself. May look on Ebay to see what I can come up with.

Did you check the 2 wire connections from the CDI to the motor?
One coming loose is very common.

That actually happened...but put them back together & took some pliers & clasped the connector tight.

Also, just disconnect the kill button from the white magneto motor wire in case it is shorting.

For some reason...my buddy had the white wire hooked to the block...because he said it needed a ground. Unhooked it when this started happening & still nothing.

Do you have detailed directions to wire these devices up with what wires go where? I have the black to black...blue to blue...but am unsure about the kill switch. If I don't hook up the kill switch to test it...will that allow me to see if either part is bad?
 
How do I actually test it without being able to get the bike started? What readings are there supposed to be & in what range if someone has a meter?

This thread now needs to be moved to the 2 cycle section. In the meantime....There are a number of ways. Peddling the bike, being towed, coast down hill and even turning the engine over with a drill/socket (removal of chain is required, don't depend on disengagement of the clutch). Remove the plug from the head and leave in the cap and grounded even if you need to wire the threads to ground. Voltage should be around 6-7 volts. Check blue to black and white to black. I use a 6V or a 12V test light. You can make one out of a 6 V (best) or 12 volt bulb like what goes in a side marker or tag light. Very low watt bulb.
 
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White wire to ground a no no, it's a hot wire. That wire carries 6-7 volts and grounding can and may of damaged the coil. Check output of coil tho.

Blue wire is hot from mag to blue on the CDI, black is grounded at mag and hooks up to the black on the CDI. The white wire is a hot output from the mag that they say is for lights, if you believe it.... specialty light needs to be used as most 6 volt lights draw too many amps.

Eliminating the kill switch will eliminate switch problems (if any) while testing.
 
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White wire to ground a no no, it's a hot wire.

I suspected this...but being my buddy has done this before...thought he would get it right. Since I'm using rubber tubing around the frame at the mounts to lessen the vibration on my wrists/body & to protect the paint...I think he thought I needed a ground to the engine. Put a pix of the build with the message & in my album.

If I'm not powering lights or some other device...that white wire is just something which doesn't get hooked up?

That wire carries 6-7 volts and grounding can and may of damaged the coil. Check output tho.

Will do that. Think I have a test light out in the pickup or my toolbox. They're cheap enough as it is if I don't. Do I check the wires going out to the CDI or open up the cover? If inside the cover...where would I put the probe?

Would this have damaged the wired U-shaped magneto as well?
 

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The white motor wire is the direct magneto 7.5V AC output when the motor is running. It is unregulated, and voltage varies with motor RPM, the faster the motor turns, the more power it puts out.

The blue wire to the CDI is please correct me if I am wrong a magneto voltage pulse send when the piston is whatever the degrees before top dead center is to fire the plug.

The black wire is the ground for the motor and this circuit.

All the kill switch does, with it's green frame wire to white magneto wire, is ground the magnetos output, killing input to the CDI along with it.

It is amazing you were able to run the motor with the white wire to bike frame.
Not just the motor mounting, but the clutch and throttle cables and chain needed to be completely isolated from the motor as well as would serve as a motor to bike ground connection.

Hahah, in fact, your whole bike had to be "energized" with voltage when the motor ran, and what ran it (the ignition system) was on it's own isolated circuit. If it actually did run that way it has to be one for the books.

Chances are you toasted the magneto.
A meter is the best to tell as a magneto coil does have some resistance, but a test light should do the test.
Just ground one end to the MOTOR, and hook the white wire to other end.
The light should light if it's good.
 
The white motor wire is the direct magneto 7.5V AC output when the motor is running. It is unregulated, and voltage varies with motor RPM, the faster the motor turns, the more power it puts out.

Sounds like anything other than battery powered lights is the way to go without spending some change on some sort of regulator setup. If that's the case...may as well get a motorcycle.

The blue wire to the CDI is please correct me if I am wrong a magneto voltage pulse send when the piston is whatever the degrees before top dead center is to fire the plug.

The black wire is the ground for the motor and this circuit.

Not sure if I'm correct or not...but when you hook up the wires to the CDI...that's where your ground comes from...rather than using the same setup with a separate huge negative wire for your ground on a car.

All the kill switch does, with it's green frame wire to white magneto wire, is ground the magnetos output, killing input to the CDI along with it.

Do I use the white wire for anything other than powering a light or something else which needs the power? Would I just cap or tape it off if I don't want to use it?

It is amazing you were able to run the motor with the white wire to bike frame.

I think my buddy was thinking the engine wouldn't be grounded without that wire being attached.

Not just the motor mounting, but the clutch and throttle cables and chain needed to be completely isolated from the motor as well as would serve as a motor to bike ground connection.

With my current build...are all these isolated?

Hahah, in fact, your whole bike had to be "energized" with voltage when the motor ran, and what ran it (the ignition system) was on it's own isolated circuit. If it actually did run that way it has to be one for the books.

It made it about 9 miles with the bronze looking tail pipe to prove it.;)

Chances are you toasted the magneto.

Wasn't sure if it was the magneto or CDI...but those are the only things which provide the power to run the engine. Am so very happy I didn't have a battery in the circuit or would be suffering from acid burns when it exploded. Seen that happen before & it's not pretty.

A meter is the best to tell as a magneto coil does have some resistance, but a test light should do the test.
Just ground one end to the MOTOR, and hook the white wire to other end.
The light should light if it's good.

Nice...will do that tomorrow since it's raining. Totally expect to find it blown.
 
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