No Spark

mshunk93

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Jun 26, 2013
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Shippensburg, PA
Lately, I've been having issues with the ignition on my 66cc gt-5 engine. One day while test driving my bike after changing the chain, I depressed the clutch lever and the motor shut off. After this, it would not start again. When I got home, I pulled the spark plug and it was cracked in half due to the way it sets up against the frame (clearance issues.) Thinking this was the problem, I bought two new NGK B6HS plugs. Still no spark.

After this, I came to the conclusion that the CDI was bad and bought a new Jaguar CDI. After installing this, still no spark. So, I ordered a new spark plug cable just to be safe and a new magneto after whipping out the multimeter and determining that it was faulty.

This morning, I installed the new magneto and it started right up. I rode it around the block a few times (running better than ever too) and parked it (with the gas on admittedly) to have a smoke. When I tried to start it back up, no ignition. Best I could get was a few sparks. Pulled the plug with the wire attached and placed it on the engine and pushed to see if it would spark. It didn't. All the electrical connections are good and everything seems like it should work but alas, it does not. The only things I could think of at this point is the magneto clearance (the bottom of the wheel is darn near touching the outer piece while the top has at least 3x this gap), and the spark plug wire (hasn't arrived yet.)

Any thoughts as to what might be causing this issue?
 
so, magneto....old style with the white wire? or new style with just the blue and black?


old one, i guess you lucked out and it fried pretty early on? if it has that white wire, cut it off and do not use it! short the blue to the black, or simply "cut" the blue for the killswitch! old style instructions say use the white for kill. old style magnetos have a bad join for the earth and burn out when the kills used too much... :rolleyes:
if its a new one...no idea. check and make sure its got a decent reading like 300 ohms.


the wire wont make a difference. full stop. when working properly, the magneto can jump a half inch gap or more! if the wire has a small break in it, it will make what used to be used on old points ignition...a spark enhancer! high voltages act funny like that.


while its good to set the magneto central, its never been an issue in my experience? loosen bolts ever so slightly, gently lever or tap in place, re tighten screws. being a wrap around type, clearance isnt critical, unlike brushcutters that need a few thou clearance.
 
so, magneto....old style with the white wire? or new style with just the blue and black?


old one, i guess you lucked out and it fried pretty early on? if it has that white wire, cut it off and do not use it! short the blue to the black, or simply "cut" the blue for the killswitch! old style instructions say use the white for kill. old style magnetos have a bad join for the earth and burn out when the kills used too much... :rolleyes:
if its a new one...no idea. check and make sure its got a decent reading like 300 ohms.


the wire wont make a difference. full stop. when working properly, the magneto can jump a half inch gap or more! if the wire has a small break in it, it will make what used to be used on old points ignition...a spark enhancer! high voltages act funny like that.


while its good to set the magneto central, its never been an issue in my experience? loosen bolts ever so slightly, gently lever or tap in place, re tighten screws. being a wrap around type, clearance isnt critical, unlike brushcutters that need a few thou clearance.

Nothing to add yet, headsmess pretty much covered it so far. But just out of curiosity I'm gonna follow this thread. It WOULD be just plain bad luck to have a new coil go bad this fast, but it could happen. I don't know how the new manual says to hook up the kill switch, But one wire to blue, one wire to black. Never ground a wire to the frame. I've seen that in some of the older manuals.
Big Red.
 
Well, the other morning I was fiddling with my bike and I decided to redo all the connections (resoldered the magneto as well,) but really didn't change anything aside from using wirenuts between the mag and the CDI. I got it to run for a minute before it cut out on me. After about 5 more minutes of tinkering, I got it to start up and I took it for a little drive to a friend's house a few miles away. An hour later, it started right up at his place and has been working ever since. Replaced the spark wire with a cool looking new blue one too and gave the wiring a permanent installation. As for the killswitch, I actually had it disconnected during this whole process to eliminate that as a source of failure. But rummaging through my toolbox today, I found a rocker switch that has a spring on one side and is normally closed that will do nicely to cut off the blue wire in-line.
 
the connection of the stator coil to the engine completes the electrical circuit of "ground" for the spark plug.
use sandpaper on all 4 screw locations for a good long-lasting electrical connection there.
 
the connection of the stator coil to the engine completes the electrical circuit of "ground" for the spark plug.
use sandpaper on all 4 screw locations for a good long-lasting electrical connection there.

Good advice.Then hook it up like this.
 

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Same exact problem, still no spark!! :(

Well, the other morning I was fiddling with my bike and I decided to redo all the connections (resoldered the magneto as well,) but really didn't change anything aside from using wirenuts between the mag and the CDI. I got it to run for a minute before it cut out on me. After about 5 more minutes of tinkering, I got it to start up and I took it for a little drive to a friend's house a few miles away. An hour later, it started right up at his place and has been working ever since. Replaced the spark wire with a cool looking new blue one too and gave the wiring a permanent installation. As for the killswitch, I actually had it disconnected during this whole process to eliminate that as a source of failure. But rummaging through my toolbox today, I found a rocker switch that has a spring on one side and is normally closed that will do nicely to cut off the blue wire in-line.

mshunk93,

I am having the same mystery as you, no spark all of a sudden, replaced the spark plug twice and the cdi, I am using the old style magneto with the white wire. I tested the ohms on the magneto at ~320 and the wires look fine to me. Still no spark, what kind of tinkering did you do that you think fixed the problem?

thanks
Roy
 
mshunk93,

I am having the same mystery as you, no spark all of a sudden, replaced the spark plug twice and the cdi, I am using the old style magneto with the white wire. I tested the ohms on the magneto at ~320 and the wires look fine to me. Still no spark, what kind of tinkering did you do that you think fixed the problem?

Most of the time it's the coil. It either failed or developed corrosion on the grounds. (what you tested is the COIL, not the MAGNETO.) The MAGneto is the MAGnet in the center of the COIL.
So, Remove the coil, Sand or scrape everywhere metal touches metal, including the black wire connector. Disconnect the kill switch and solder everything else together for now. Make VERY sure no wires are touching anything. Put a new plug wire and boot on it and see what happens. If it is a bad connection this should do it. If not and yer still getting 320 out of the coil then it's probably the CDI unit. These don't go bad as often as coils, but they DO go bad. I always keep one of each (coil&CDI.) in stock just for my personal bike. I hate waiting a week to ride my bike.
Big Red.
 
stock CDIs are very marginal at best. If the magnet has lost some strength then the magnetic flux that powers the stator coil may not be enough for it to output enough voltage to the CDI. Stock CDIs have overly advanced ignition timing which causes higher peak pressure/temperature in the cylinder. This causes excess engine temperature. People have reported over 500 degrees F as a result. This paper says that heating a ferrite magnet over 460 degrees causes it to lose magnetic strength. http://www.coolmagnetman.com/magstren.htm So you need to replace it and, for god's sake man, get a Jaguar CDI! :)
 
more troubleshooting...

Most of the time it's the coil. It either failed or developed corrosion on the grounds. (what you tested is the COIL, not the MAGNETO.) The MAGneto is the MAGnet in the center of the COIL.
So, Remove the coil, Sand or scrape everywhere metal touches metal, including the black wire connector. Disconnect the kill switch and solder everything else together for now. Make VERY sure no wires are touching anything. Put a new plug wire and boot on it and see what happens. If it is a bad connection this should do it. If not and yer still getting 320 out of the coil then it's probably the CDI unit. These don't go bad as often as coils, but they DO go bad. I always keep one of each (coil&CDI.) in stock just for my personal bike. I hate waiting a week to ride my bike.
Big Red.

Thank you for the advise Big Red,

The first thing I replaced was the CDI, when I did so I did not know about the order in which you are supposed to hook up the wires from coil to cdi and may have done it backwards, causing this new CDI to malfunction. Today I tested compression, it was fine. I also took to nut off the magnet to check and see if it had shifted over some, but the magnet key seems to be aligned properly.

I have cut off the white bulb wire completely from the coil and am going to re-wire it and solder everything together. I will also find out how to measure the CDI to make sure its not the culprit, I can do this with a multimeter I suppose.

If there is anything I'm not checking let me know. Thanks for the help,

Roy
 
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