Cdi readings

Wevil Knievel

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Apr 5, 2021
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Ive read some much conflicting blah blah blah on here Im totally lost.

my bike was running I went to change the handlebars and when I put the it back together it wouldn't run.

The clutch and clutch cable are fine
The throttle cable is working properly.

There's plenty of gas, the line is not clogged the carburetor is full of gas. Pushing the priming button it causes gas to split up into the carburetor and out the front of the little breather hole.

With my multi tester set at 20K, The Magneto readings (3.4)fall within the guidelines and is wired properly and insulated.

The kill switch has been disconnected from the harness.

The spark plug wire is good as is the plug.

The cdi reads you 4.18 on one and 4.21 on my spare.

Are both bad or am I missing something here?
 
Is there a good cdi troubleshooting guide on here?
Idk I cant find it if there is. I just got a new one and it reads the same as the others.

There was a short in the electrical wire running to it is why it wouldn't start. But if you put your tester on continuity and test all of the wires it should read between 4.15 to 4.50 if it's good I don't know what the reading would be if it were bad.
 
CDI resistance measurements are not very reliable since the capacitance will throw the readings out of whack. If you managed to get a good reading on the magneto coil, it should be ok. There are a couple of things I would check though:

- Measure resistance between the black wire from the magneto to the engine case. You should see close to 0 ohms

- Verify that the CDI wires are making good contact with the crimped on bullet connectors. A visual inspection may not be adequate here. What I do is stick a safety pin into each CDI wire as close to the case as possible, and measure resistance from the terminal to the safety pin. If you see 0 ohms, you should be ok.

- Verify that the spark plug wire is making good contact with the CDI. These are actually screwed on, and can be removed and reattached. Sometimes, all that's needed is just cutting a 1/2" off of the bare end of the wire and screw it back down.
 
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