Replacing entire electrical system? Please help.

The-DMV

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Feb 5, 2017
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I've been getting a very weak spark or no spark at all since I first ran my bike last week. The first time I tried starting it, it ran great for half a mile, and then started to lose power and sputtered out and wouldn't start again. I tested the wires with a meter and I thought the CDI might be the problem, so I ordered a new one, and it started right up and ran great for half a mile before the same thing happened again.

So I ordered a new magneto and NGK spark plug, and it ran great for a few minutes, and the same thing happened again. I thought that maybe the CNS carb wasn't giving the engine enough fuel, so I raised the float level and tried starting it some more. I pulled the spark plug out and it was drenched in fuel. Turning the bike over and holding the plug to the engine head doesn't get any spark. The only thing I haven't replaced is the magnet, but it seems okay.

Any ideas?
 


Frankenstein

In memory of Frankenstein 1991 - 2018
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Too much fuel and too many incidental occurrences at one time?

As the engine rides it stops, you replaced electrical components enough times it's probably not that. So maybe too much fuel, over rich is nice when starting but too long it starts to bog the motor and flood with too much vapor.

You should check the carb for signs of it staying too rich, maybe a jet too big or loose. Cns carbs are tricky if you don't know what you are doing and they are hooked up wrong on the hoses.

How is your choke or enrichment engaged?

Small chance it's slow fuel flow, but taking the bowl off the carb and turning the fuel line on would indicate that problem, if it's a light trickle it's probably bad, a pouring is more wanted.
 

KCvale

In memory of KCvale 1959-2019
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This is somewhat dated, but it gets right to point of the whole elctrical system, how it works, and how to test it.

http://kcsbikes.com/topic.asp?TOPIC_ID=623

Yes, it IS possible to have a bad magnet, seen it, it is stuck to the front of my medal filing cabinet. It still has some magnetism, but not enough to generate usable power with the magneto.
 

Frankenstein

In memory of Frankenstein 1991 - 2018
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This is somewhat dated, but it gets right to point of the whole elctrical system, how it works, and how to test it.

http://kcsbikes.com/topic.asp?TOPIC_ID=623

Yes, it IS possible to have a bad magnet, seen it, it is stuck to the front of my medal filing cabinet. It still has some magnetism, but not enough to generate usable power with the magneto.
True, I'm guessing not a magnet, if they were able to get it started at all the magnet must be doing the job well enough to keep going, in fact it gets easier for the motor to run as it heats up, you know that but pointing it out anyway, since it may be useful to other diagnosers.
 

Randall

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May 23, 2016
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True, I'm guessing not a magnet, if they were able to get it started at all the magnet must be doing the job well enough to keep going, in fact it gets easier for the motor to run as it heats up, you know that but pointing it out anyway, since it may be useful to other diagnosers.

Maybe a shorted wire(???)
 

Frankenstein

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Maybe a shorted wire(???)
But to run and then stop after a couple blocks? More than once? Seems too unlikely that a short is the issue after being set up new twice. Never know, coincidences are real things..
 

Randall

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But to run and then stop after a couple blocks? More than once? Seems too unlikely that a short is the issue after being set up new twice. Never know, coincidences are real things..
I disagree. Hitting a bump could have caused it to to short out. He should check for loose and exposed wires. And a loose magnet anything electrical that may be loose.
 

Frankenstein

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I disagree. Hitting a bump could have caused it to to short out. He should check for loose and exposed wires. And a loose magnet anything electrical that may be loose.
Hey if it's the same bump and same bad electrical job then why not lol...
 

Frankenstein

In memory of Frankenstein 1991 - 2018
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It's really terrible that it seems that there are more gremlins in these things than you could find in vehicles manufactured a hundred years ago even though those vehicles are vastly more complex.

At one point I have a hard time determining if it's the engine or the person's inability to maintain the engine that's the problem...
 
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