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Discussion Starter #1
So I cranked my bike it running on one cylinder again I take a timing light hook it on the back cylinder plug wires there getting really weak fire and the coils are good cause I switched them around and it still cranked on the front what you guys think im lookin at here?
 

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Hondas use what's known as a "fast spark."

it will look pale, yellow and possibly slightly purple. it will not be a fat blue spark like your lawnmower makes.

A fast spark is very efficient at igniting gasoline.

If this is the spark you're seeing, it's perfect for your bike.

--Justin
 

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Discussion Starter #3
well it not just weak fire sometimes its no fire? I got stuck coming back on one cylinder luckly I was close to my house. I switched the coils from back to front and the same thing happened so I ruled out the coil being bad, cause it works just fine on the front cylinder its really wierd
 

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Try switching the spark plugs from front to back. If you switched the coils and got the same results it doesn't leave much else.

One additional thought. Check to see if you have good fire going to the rear coil. If you switched coils and get the same results that could be a problem if both coils are good.
 

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You're keeping both plugs grounded, right? The plugs are in series, like old Christmas lights. If one can't fire, the other can't fire either.

Also, does this happen when the bike is only hot? Or does it do this all the time? I'm thinking you may have a pulse generator issue is all else checks out.

--Justin
 

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Hmmm, I think I may be wrong on this. On the older Shadows, like I mostly work on, there's a separate pulse generator for each cylinder. On the newer ones, like yours, I think there's only one that runs both cylinders. In this case, either both cylinders work, or both don't.

Pulse generators don't seem to have an intermittent fail mode, except when they are failing hot. In this case, they stop when they got hot, but work fine cold. Since yours doesn't work cold either, I don't think it's the problem.

If you want to check it out though, it's a coil of wire inside the crankcase that detects the crankshaft position and tells the ignition module when to fire the plugs.

My bike has two, one for each cylinder. The wires are White/Blue and Blue for one, and White/Yellow and Yellow for the other. They plug into the ignition module. You should get a resistance of more than 150 ohms and less than 1,000 ohms. I give a broad range since coils are tough to test. Basically, you want more than 10 and less than infinite.

Not sure what color the wires will be on your bike, or how many pulse generators you have on your bike. In any case, it doesn't sound like they are the problem.

--Justin
 
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