Bad Magneto, How To Tell

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Watts

Watts

New Member
Mar 22, 2010
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Ontario
Had a few posts on this forum that lead me to think that my mag or the wiring to my mag was shorted or burnt. So I decided to inspect the mag, after inspecting the mag it seems that all the wires rae connected solidly to the mag with no burn areas around the connection or on the mag. I have included a picture of the mag.

I was at a point where I could only get my bike moving forward by holding down the killswitch, now that doesnt work either so I want to make sure its a bad mag not CDI. Anyway to tell. The mag looks fine and all wires to mag look fine. Any ideas on how to determine if a mag is working, is it possible that it may look fine (no burns) but still be shorted (even though wires are connected fine with no burns)

Thanks

Watts
 

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Watts

Watts

New Member
Mar 22, 2010
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Ontario
Aaron F, thanks tried that earlier no luck....still wont work with killswitch removed from equation

Thanks

Watts
 
AaronF

AaronF

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Aug 24, 2009
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Hm was the mag or coil wet when you took off the cover? I'm sure you already know this,but recheck your wiring and plug wire to cdi and spark plug cap.
 
Watts

Watts

New Member
Mar 22, 2010
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No mag was dry so was coil, no moisture build up or anything. My wiring goes blue to blue and black to black with white capped off. How do i check wiring in CDI, i took off CDI box and cant see anyway to open it to determine if the spark plu wire etc are connected correctly inside the box.

Also how do I check my spark plug cap

Thanks

Watts
 
AaronF

AaronF

New Member
Aug 24, 2009
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Turn the spark plug wire clockwise into the CDI same with the spark cap make sure they are tight.Check inside the spark plug cap to make sure the little screw 'connector' is also in there good.
 
K.i.p

K.i.p

New Member
Nov 8, 2009
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CNY
I found this in my personal stash of important things to know. I believe it is originally from Norm. Maybe it will help. You should be able to run the check using the ground lead rather than frame ground I would think.

"with the meter set to ohms put you meter on the blue wire and a frame ground you should have around 300 ohms or more.check the white wire to ground on the frame should be around 2.5 ohms do these with the cdi disconnected."
 
Venice Motor Bikes

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,271
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Los Angeles, CA.
It's my personal experience the it's almost always the mag that goes bad & not the CDI.
Also, when you install the new mag; don't use the white wire for the kill button! Hook the kill wires to the blues & blacks! I've found over the years that using the white wire can cause problems such as yours. ;)
 
Watts

Watts

New Member
Mar 22, 2010
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Ontario
Does anyone know where a good place to order a magneto from is? Remember I am located in Canada and sometimes UPS can try adding brokerage fees to shipments comming from USA.

Any ideas whos cheapest, most reliable, and fastest in shipping parts? Or am I just better buying a new 80cc kit for $150 and use the parts from that, that way I have backup parts.

Specially if I am going to end up paying $50 or more for a magneto to be shipped I might as well buy a new engine kit?

What do you guys think?? I have the extra money but also dont want to waste it. The place also sells 4 storke engine kits, im guessing magnetos for 4-storke kits are different from 2-stroke?

Thanks

Watts
 
Venice Motor Bikes

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,271
1,810
113
Los Angeles, CA.
Watts said:
Does anyone know where a good place to order a magneto from is? Remember I am located in Canada and sometimes UPS can try adding brokerage fees to shipments comming from USA.

Any ideas whos cheapest, most reliable, and fastest in shipping parts? Or am I just better buying a new 80cc kit for $150 and use the parts from that, that way I have backup parts.

Specially if I am going to end up paying $50 or more for a magneto to be shipped I might as well buy a new engine kit?

What do you guys think?? I have the extra money but also dont want to waste it. The place also sells 4 storke engine kits, im guessing magnetos for 4-storke kits are different from 2-stroke?

Thanks

Watts
Click to expand...
Have you checked any of the ads on the sides of this page??? :rolleyes:
 
2

2T'S

New Member
Jan 19, 2011
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92054
] I am haveing the same problem!!!!NO SPARK ! ! I installed a new CDI as well as a new magneto. still to have no spark. Please somebody help me! Do we need to time this motor when installing an new magneto?
 
Last edited:
Dave31

Dave31

Active Member
Mar 1, 2008
11,199
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38
Aztlán, Arizona
2T'S said:
] I am haveing the same problem!!!!NO SPARK ! ! I installed a new CDI as well as a new magneto. still to have no spark. Please somebody help me! Do we need to time this motor when installing an new magneto?
Click to expand...


I would say your problem is elsewhere. Have tried a new plug? Is your wiring correct and all connections making contact? Do you have your kill switch hooked up and if so have you tried to disconnect it? Is your plug wire installed correctly and making contact with cdi? Is your magneto making contact with the rotor, it should not.
 
crassius

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
hold the plug in your hand, hold your hand against the engine and crank it over - you'll feel it if there's a spark that you just aren't seeing
 
Last edited:
B

bradley J kubecka

New Member
May 6, 2019
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Dave31 said:

I would say your problem is elsewhere. Have tried a new plug? Is your wiring correct and all connections making contact? Do you have your kill switch hooked up and if so have you tried to disconnect it? Is your plug wire installed correctly and making contact with cdi? Is your magneto making contact with the rotor, it should not.
Click to expand...
I'm having the same problem too and I replaced the cdi, mag, spark plug, carb and cylinder body all are brand new. Could something else be causing this problem? Also should be noted that I'm only having these problems after my bike Seized up on me.
 
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