Post if your magneto failed due to moisture

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UVsaturated

New Member
May 15, 2008
140
4
0
Dayton, Ohio
Just curious of those who have had your magneto fail due to rain or moisture. My ignition failed and after checking the CDI and magneto with a meter, I determined the magneto was bad. I have not replaced the mag as of yet (getting ready to purchase a new one), but noted that when this occurred it was a day or so after riding it in a heavy rain. I had not sealed the rubber grommet either so I am pretty sure that moisture was able to get in and do some sort of damage, but I didn't realize it would go out suddenly.

A day or two after the rain event, I began to ride it and got about a 1/4 mile then suddenly it just quit.

So only those with bad magnetos, post if you too had a problem with getting the mag wet and then having it fail miserably.
 
Moto

Moto

Member
Jan 7, 2012
403
15
18
San Francisco, CA.
Yes, I went camping with my friend and his bike (my replacement motor was in the mail) and it rained that night. The bike was under a tree, but it still got wet. The bike worked fine until he took a sharp turn and water (trapped in the magneto compartment) splashed up on the magneto. Dead. I replaced his with the one from my dead engine and the engine started right up. dance1
 
Dave31

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
My float stuck open one time and flooded my mag with fuel when I tried to start it before I realized what was happening. Two days later my mag went out.

I also had one fail when I rode in the rain and got water in the mag, it stopped working right away. Sprayed it out with WD-40, it worked for about a day then the mag went out completely.
 
Moto

Moto

Member
Jan 7, 2012
403
15
18
San Francisco, CA.
Today I opened up my mag compartment just to check things out, turns out I have the new style 4 bolt mag! Kewl. Anyway I was closing it up and decided that the cereal box grade stock gasket wasn't going to keep any water out so I tossed it and but a bead of this marine / auto silicone in its place, looks like its gonna work awesome! Btw the silicone is good for 400 degrees so I think its good. I also sealed up the little bung thing that keeps the wires in place were they come out.
 
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vachon644

New Member
Nov 27, 2011
95
0
0
Quebec city, QC, Canada
I had one magneto die on me too. It was a day or so after I rode in heavy rain, I suspect that either the rubber plug or the gasket failed. Anyway, once dried it wouldn't work so I replaced it. It happened again with snow (I love riding in winter time) but this time it worked once dry. I sealed it up good with some permatex gasket maker. I tried some RTV sillicone first but I found out that the product wasn't really holding well against the aluminum of the engine and I tried this permatex gasket maker which is more like a paste; since I haven't reopened the magneto casing and haven't had any problems with it. It's really something the chinese should redesign as it is a common problems for chinagirls to get wet and fry.
 
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sleepy hollow

New Member
Apr 28, 2012
85
1
0
huntington beach ca
I think my crank seal is seaping, my original mag fried due to moisture, so i bought 2 new mags and after 2 weeks the mag burned out again, and i know its not my mixture because my plug is perfect, but i think the crank seal is bad, break in was just rich mixture with 20mph speed, other than that i ride 30 mi, a day. 98% of thatmy rpm are between 5800-7200
 
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vachon644

New Member
Nov 27, 2011
95
0
0
Quebec city, QC, Canada
@sleepy_hollow : Seal the magneto cover well and go over every connection making sure it's good and well insulated because if the magneto shorts itself out the current it creates has nowhere to go and it might heat it's tiny gauge wires which can burn thus killing the magneto. I don't think that a crank seal can go bad because of rich mixture but it may be bad from factory; You can block your piston with a rope through the spark plug hole and remove your magnet, there should not be any gas/oil seeping through there. The seals are put in with some grease so they may not be perfectly dry though.
 
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sleepy hollow

New Member
Apr 28, 2012
85
1
0
huntington beach ca
vachon644 said:
@sleepy_hollow : Seal the magneto cover well and go over every connection making sure it's good and well insulated because if the magneto shorts itself out the current it creates has nowhere to go and it might heat it's tiny gauge wires which can burn thus killing the magneto. I don't think that a crank seal can go bad because of rich mixture but it may be bad from factory; You can block your piston with a rope through the spark plug hole and remove your magnet, there should not be any gas/oil seeping through there. The seals are put in with some grease so they may not be perfectly dry though.
Click to expand...
Its the seal becaus the mag is coated with oil, i came up with a solution, i siliconed over the mag windings, sealing the mag xct2
 
C

Cycloptishred

New Member
Mar 30, 2012
34
0
0
Eugene OR
Pretty sure mine just went out. I ride in the rain alot and it never went out. Until 2 days ago when it just didnt want to start back up after I killed the motor for a traffic light. Any tips on how to keep this from happening?
 
Dave31

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
Cycloptishred said:
Pretty sure mine just went out. I ride in the rain alot and it never went out. Until 2 days ago when it just didnt want to start back up after I killed the motor for a traffic light. Any tips on how to keep this from happening?
Click to expand...
Use some rtv to seal the cover and also the rubber grommet for the wires.
 
M

Mikeywizad

New Member
Oct 3, 2012
2
0
0
USA
Yup ! got caught in the Heavy Rain twice in 2 days now .... Bike died almost home ... got up this morning ...and thought water entering the carb had been the problem ...but after everything I tried ....I realized that I had no spark.

Put a small screwdriver into plug wire and held it in my hand while I popped the clutch ...nothing ...not even a tingle.

I opened the magneto case ...and water drained out of it ...GRRR. ...will order two mags Friday ...install one and seal the case well . The other will be in a baggie in a box on the rear bike rack ....along with the spare carb ,head gasket ...tire tube etc.:-||
 
CTripps

CTripps

Active Member
Aug 22, 2011
1,310
1
38
Vancouver, B.C.
I had one die on me not long ago from possibly getting wet. When I got to work that morning and locked up the skies were clear, with a forecast of nice all day. I have a cover for wet days, decided not to use it. Mid morning we had a 15 minute medium-heavy rain. The bike started up to go home, but when I made the U-turn in the back lot to head for the gate it stalled out and died. No reading from the black wire when I got the tester on it. My mag case was siliconed all around, including the grommet. I'm thinking water wicked in down the wires themselves inside the 'insulating' sleeve they are all bundled through.
I have two dead mags now, I'm thinking it's time to learn how to fix them (if I can) myself.
 
Wickedest1

Wickedest1

Member
Oct 31, 2012
688
7
18
41
connecticut
CTripps said:
I had one die on me not long ago from possibly getting wet. When I got to work that morning and locked up the skies were clear, with a forecast of nice all day. I have a cover for wet days, decided not to use it. Mid morning we had a 15 minute medium-heavy rain. The bike started up to go home, but when I made the U-turn in the back lot to head for the gate it stalled out and died. No reading from the black wire when I got the tester on it. My mag case was siliconed all around, including the grommet. I'm thinking water wicked in down the wires themselves inside the 'insulating' sleeve they are all bundled through.
I have two dead mags now, I'm thinking it's time to learn how to fix them (if I can) myself.
Click to expand...
If you can figure out how to rebuild the mag please let me know...I'm not in a great financial spot so a rebuild would be great for me...thanks
 
biknut

biknut

Well-Known Member
Sep 28, 2010
6,632
411
83
Dallas
I had 3 magneto coils fail this summer one after another. The coil windings went open on all 3. It had nothing to do with moisture.

After the last one failed about 3 months ago, I disconnected the kill switch. I haven't had another failure.

It seems that the way the stock kill switch works by shorting the coil windings together, isn't good for the windings.
 
biknut

biknut

Well-Known Member
Sep 28, 2010
6,632
411
83
Dallas
biknut said:
I had 3 magneto coils fail this summer one after another. The coil windings went open on all 3. It had nothing to do with moisture.

After the last one failed about 3 months ago, I disconnected the kill switch. I haven't had another failure.

It seems that the way the stock kill switch works by shorting the coil windings together, isn't good for the windings.
Click to expand...
A better way for the kill switch to work would be to open the winding. This is how most motorcycles do it.
 
biknut

biknut

Well-Known Member
Sep 28, 2010
6,632
411
83
Dallas
Also I don't think it's a good idea to completely seal the magneto compartment, because it will condensate. There needs to be a way for condensation to escape.
 
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