Wico X Mag

[Buddy Woodson]

How do you check a coil for this mag? Thanks, Buddy
 

[John T]

A simple low voltage ohm meter test will tell you if its really BAD (like the LV Primary or HV Secondary is open) but it cant tell you if its really GOOD since many failures involve High Voltage Breakdown and/or occur only after its warmed up and under actual operating conditions. The LV Primary is less then 1 ohm while the HV Secondary is several thousand ohms and if either is open its obviously bad.

The most common cause of mag failure to spark is the points are burned or pitted or even gray oxide coated any of which kills the spark. You might clean n light file them and gap them n see if that cures the problem and replace if badly burned or pitted. Likweise a bad condensor can cause no spark.

Since points and condensor are relatively cheap compared to the coil if the coil passes both continuity tests and doesnt appear or smell burned Id suspect points and/or condensor first.

For the impulse cranking spark to happen the mags wind n trip spring assembly has to be working and it yields a good sharp SNAP each 180 of rotation otherwise no spark at cranking speed.

John T
 

[Buddy Woodson]

Thanks, exactly where do you touch the leads of the tester?
 

[Buddy Woodson]

Also, should the coil fit snug on the cross bar? Mine is loose.
 

[John T]

The LV Primary is between the little wire from the coil that connects to the points and case frame, points need to be OPEN...The HV Secondary is from the coils side output button/terminal (where caps springy touches) to case frame. If it has the side push springy kill switch that also is the wire from coil to points and with points closed you should show 0 ohms to case frame but with them open the less then 1 ohm which would be again the LV Primary of the coil. NOTE the condensor wire also attaches to the points where the coil wire does so that should be removed cuz if the condensor were a short that messes up the LV coil primary measurement.

John T
 

[John T]

It should be fairly snug, thats the purpose of the little paper wedges that fit between the coil center where the bar passes through.