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Discussion Starter · #21 ·
What I've done to test the coils is extend the wires from the front one to the back one and that makes the back one fire perfectly. Then I extend the back coil wires to the front one and it fires as expected.
That tells me both coils are good.
I have unbolted the coils and clean their grounds just to make sure.
That said, I'm not too far from going crazy.

I appreciate all of you guys imput.
Please do not hesitate to keep sending any ideas you might come up with.
Some how I have the feeling this is one of those cases where I am missing something stupid. I am sure that with the brain power in this forum someone here is going to catch it.

Thank you!
 

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Ignition switch ?

Kickstand cut out switch ?

Also keep in mind that intermittent can be when engine is warm and test fine when engine is cold.
 

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Rear cylinder Compression Reading ?

If the rear piston, rings, valves are in good shape and sealing as they should, then it must be electrical.

You will have to play detective and you may end up at a shop with high end equipment.

Somebody earlier mentioned the Rev limiter cutting out the rear cylinder. Are you sure
this is not the problem ?
 

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Discussion Starter · #25 ·
I did not see the comment before about the Rev Limiter.
Isn't that just a function of the CDI?
I have not seen any mentions of it in the electrical diagrams, or anywhere in the books.

Does anyone know where is it and if it can be tested?
 

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I personally do not know anything about the rev limiter. Or testing.

I'm sure someone on here will chime in soon.
 

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Both coils have been checked. If I take the wires from the front coil and connect them to the back coil it sparks. But if I do the reverse it doesn't.
OK I'm confused here. If you are essentially swapping wires and one way works but not the other...haven't you just found the problem? Maybe I'm not understanding exactly what you are saying.
 

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So then the coil wires to the rear cylinder are suspect. I would trace every inch with a needle tip probe
and multimeter and check continuity.
 

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Discussion Starter · #31 ·
I know, this is as confusing to you guys as it is to me.

@restorider, I did that...I even jumped the wires directly from the CDI to the rear coil just to bypass the original connection and nothing.

Thank you for all your help, advice and ideas...they just confirm that I am on the right path, but still no success.

Please don't give up on me...LOL!


I have been given the thought of checking the Rev Limiter, but so far what I've found out is that is a function of the CDI so nothing to do.

Plus if it was the RL, woundn't just slow the spark not just cut it off completely?
 

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Both coils have been checked. If I take the wires from the front coil and connect them to the back coil it sparks. But if I do the reverse it doesn't.
if you take the wires from the front coil and connect them to the back coil it works, do you mean the rear cylinder works.
i think the rev limiter cuts power to one cylinder, my thought was where it gets its information. if its getting a signal from the speed sensor or maybe the tps everything goes thru the cdi.
 

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Discussion Starter · #33 ·
WELL GUYS I HAVE FINNALY FOUND WTF WAS WRONG WITH THIS DEMONIC BIKE.


The pickup coil wires were reversed...

When I bought this bike the previous owner told me that he had some problems and the mechanic, after doing some work on it and charging him for it, told him that it also needed a CDI box. The owner told me he did not wanted to spend more money on it and just wanted to sell it.

He wanted $1500 for it but I only paid $900.

So the first thing I did was to buy a used CDI on eBay which of course it did not work. And that's when this ordeal started.

Long story short, awhile ago, I did change the pickup coil as another posible solution and I followed the wires just as they were.

So, my conclusion is that the mechanic, after changing the pickup coil and reversing the wires had the same problem. He could not figure out what was going on so was trying to have the owner pay for one more thing (CDI) trying to figure out what was wrong.

As soon as I reversed the wires I got spark and the bike fired right away beautifully.

I thank you all very much for all your advice and help.

One thing for sure I know this bike in and out and after cleaning the carbs a couple of times it is running like a champ.



HAVE A HAPPY, HEALTHY AND WITH PLENTIFUL OF SAFE RIDES NEW YEAR!!!!
 

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Hooray, Thankfully there is a god up there.
 
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He needs winter just to cool the tools off...

And he saved $600 on purchase price for said swapped wires > Priceless !
 
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Glad you got her fixed. And you learned some stuff in the process.
 
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CDI boxes

modern motorcycles don't use a CDI ignitions they use a TCI... capacitor discharge ignitions are mostly on older or smaller bikes like dirt bikes and such. the TCI or transistor controlled ignition is way more reliable and can handle 10,000 rpm with no problem. one of the main differences are the ignition coils are a very different animal, their actually step-up transformers so the coil terminals are both primary, that's why there's no + or - markings on them
 

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if you take the wires from the front coil and connect them to the back coil it works, do you mean the rear cylinder works.
i think the rev limiter cuts power to one cylinder, my thought was where it gets its information. if its getting a signal from the speed sensor or maybe the tps everything goes thru the cdi.
for the rev limiter,
there's a microprocessor in the ecm that kills one coil when the coil starts tripping to quickly. the TPS helps control the spark advance curve.
 
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