Magneto replacement?

[Nerevar]

I was wondering if any of you knowledgeable bike builder types know if there is a guide to replacing the magneto. I was riding in the rain the other day and my magneto got wet; and lo and behold there was no spark. Can it be rebuilt? Will drying it off save it? Does the magnet have to be in a particular position in it's rotation in relation to the coil in order to fire properly? Thanks in advance.

[misteright1_99]

Drying it off might fix it, if getting wet didnt fry the CDI. I read somehwere that you just unbolt it from the two mounting points, then when placing the new one in wrap something like a business card around the magnet, till it is mounted, then remove the card. I imagine this helps with centering the magnet.

[Dave31]

Spray it with some WD-40 and give it a try....if you are lucky nothing got smoked.

To remove the mag, just unscrew the four bolts. To re-install it, start with one bolt, then another and so on. Do not tighten them until you have all the bolts in. Just a little wiggling will get the job done.

[jasonh]

You can also bake it in the oven for a bit to cook off some of that moisture inside. 250 degrees maybe for 10 min or so. Worth a shot.

It's probably dead though.

[Norman]

or until its a light golden brown.
Gee I wish the old snake would make some cholate chip cookies that made me hungry.

[Nerevar]

Well i tried all those things... my magneto is now a nice golden brown caramelized glaze on the outside. And I still have no spark.

I'm thinking its got to be either the mag or the CDI. How do I figure out which one failed? I do have a multi-meter - i just don't know how to test and what to look for.

Any suggestions?

[jasonh]

You can find the required values here:

http://motorbicycling.com/f34/no-spa...kill-2102.html

[lylespen]

Hi-new member, been lurking for a few weeks, learning a lot from very valuable site, as I complete first Bikeberry Raw kit. Have common "no spark" problem--wiring appears to be correct, dry, stop switch disconnected, plug out, no spark as spin mag. I see thread references to a table of multimeter troubleshooting readings: cdi expected ohm resistance, mag and cdi expected voltage when spun, but can't find it. Would GREATLY appreciate URL ref.

And one minor contribution re. engine, cdi, cutoff switch wiring heat and other damage protection: use 3/4 in. flexible aluminum electrical conduit (mine left over from hot water heater installation, conduit required by FL building code). Thanks

[jasonh]

CDI pack GOOD 
Black to Blue 1150kΩ 
Black to Plug 2.6kΩ 
Blue to Plug 1150kΩ 


Magneto
Blue to White 327Ω 
Black to Blue 327Ω 
Black to White 2.1Ω 
Black to Gnd 0Ω 
Blue to Gnd 327Ω 
White to Gnd 2.1Ω

[Creative Engineering]

nerevar,

It is highly unlikely that the Mag was affected by a little water. If it got submerged maybe...but if it was a little damp I doubt it. They aren't that delicate. The CDI is. I suppose if the wire connectors got really wet the CDI may have shorted and popped one of the IC's. If you find that the mag coil is bad, I would attribute it to coincidence as opposed to a little water.

Are you using the original bullet connectors that connect the mag to the CDI? They are so crappy that they can appear to be well connected when actualy they're not.

If your Ohm readings are correct per Jasons' post try crimping on some new connectors. Also change the plug and plug wire...it's cheap and easy to do.

Jim