no spark @ my whits end

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G

GSX

New Member
Jun 15, 2012
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Ray Brook
Hey everyone. On my way to work my bike was 4 stroking worse than normal and just all of a sudden farted and cut out on me. I tried like **** to start her back up but to no avail. I got 2 or 3 pops out of about 300 yards so i took the kill switch off figuring that may be the problem, that accomplished nothing. Once i got back to the shop, pulled the plug(black and wet/oily) so i threw a new a new plug in hoping this was just a fouled plug. That did not work. I checked for spark and still have nothing. Took my cdi off the bike, looks nice and dry with no cracks/burns/whatnots. I took my multimeter, put it on 2000k ohm setting and this is what i got
CDI
black to plug cap: 011
Blue to plug cap: no reading
Black to blue: no reading

Safe to say my cdi is shot? Iv been looking all day for a manual on how to test cdi but did not find anything so if someone has any tips i would appreciate very much
 
G

GSX

New Member
Jun 15, 2012
14
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0
Ray Brook
Correction: my multimeter is a bit old and junky, after redoing the contacts this is what im getting @ 20k setting
Black to plug cap: 12.43
Blue to plug cap: no read
Blue to black: no reading

Anyone have any clue what the readings should be?
 
N

nightcruiser

New Member
Mar 25, 2011
1,180
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USA
I just took a new (never used) cdi and made some measurements with a Fluke 76 multimeter.....

Black to Blue - Increasing to infinity (open after capacitor is charged)

Black to Plug wire - 12.56K Ohm

Blue to Black - 2.175M Ohm

Blue to Plug wire - 2.185M Ohm

Plug wire to Black - 12.55K Ohm

Plug wire to Blue - Increasing to infinity (open after capacitor is charged)

Common lead on the first listed connection for the above measurements.
 
G

GSX

New Member
Jun 15, 2012
14
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0
Ray Brook
Hey thanks a bunch. One more small question: i pulled my magneto cover and was wondering how to measure voltage output? Is it ac or dc? Im checking blue to black coming out on 20dcv setting and 200 acv setting. Acv seems to put more out. Reason i ask is i had some moisture inside the cover. Ill check the cdi again with a better meter and report back. Thank you once again
 
N

nightcruiser

New Member
Mar 25, 2011
1,180
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USA
If you have moisture under the magneto cover you probably found your problem. I would pull the magneto out, dry it out well, resolder all the connections on it, sand the bottom side where it hits the case when mounted and remount it. If it still doesn't fire I'd try a new magneto. (and magneto cover gasket if yours is missing or leaking)
 
N

nightcruiser

New Member
Mar 25, 2011
1,180
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USA
The output from the magneto is driven by the motor, when the magnet rotates it creates a pulse from the magneto. The output is an extremely rough AC voltage, the frequency and magnitude depends on how fast the motor is turning. In other words, its hard to measure....
You can however measure the DC resistance of the magneto pretty easily, and check for shorts between the two windings. Check out this link for more info and approximate values you should measure.....
http://www.grubeeinc.com/USA/Magneto Mystery.html
 
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G

GSX

New Member
Jun 15, 2012
14
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Ray Brook
Will try that also, i really think the cdi is the one that conked out on me. Only reading im getting is black to plug cap @ 12.28 and no reading on any other wire.
 
G

GSX

New Member
Jun 15, 2012
14
0
0
Ray Brook
Tried another meter we have here and getting same results. Black to plug i get a reading, all the other connects are open without a charge or a "burst" you get(dont know any other way to put it)
 
N

nightcruiser

New Member
Mar 25, 2011
1,180
2
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USA
GSX said:
Tried another meter we have here and getting same results. Black to plug i get a reading, all the other connects are open without a charge or a "burst" you get(dont know any other way to put it)
Click to expand...
Are you using an auto-scaling meter? If not, note that some of the readings are in K Ohm and others in M Ohm.

Also, once the capacitor has been charged it will hold its charge for a while and those readings will continue to hold at infinity (open), you will see no "burst" on the meter if the cap is already fully charged.
 
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