CDI Stator Explained and Test(Simple)

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CDI Stator Explained and Test(Simple)

Postby Gman » Sat Jul 26, 2008 8:22 pm

Note:The 3 yellow wire tests can used on the,"Charging Only" G8 style Stators as well.

The Stator in the CDI CX bikes serves two basic functions.

1:Charging the battery.
2:Supplying a High AC voltage for the CDI ignition unit.
The Stator in the Transistor Ignition bikes only supplies the charging system but the 3 yellow wire checks are still valid.

Picture courtesy of Wemoto spares.

The two Larger Bobbins you see supply a the High Voltage AC for the CDI Ignition(Black or gold box under the seat on top of the mudguard) unit.

The other coils/bobbins are arranged electrically as two circuits so that if the lights are off only one set of them is used and when you switch on the lights it brings in the other sets.

Using a Multimeter

Test 1:

Set the Multimeter to DC 20v range and connect across the battery with the bike on the Stand and idling.
You should read between 13.8v and 14.8v
If it is in this range your system is charging and supplying enough current to keep the battery in a charged state
under normal running.If outside this range you may have a fault.

Test 2:
Pull the block from under the seat that has 3 YELLOW wires coming from it.

Set the Multimeter to the 2k resistance setting or the lowest one on the meter or if it has a,"Continuity" setting like mine that beeps use that.

Check blades 1 to 2: 2 to 3 and 3 to 1.They should all have a zero or very low reading or in my case,"Beep".This means they have continuity e.g none of the coils are broken.If there is any high resistance then there is a fault in the Coils or the wires leading to them.

Test 3:

Using the 2k resistance setting/Continuity test again,

Attach the multimeter to each blade one at a time with one end of the Multimeter and touch the other end to somewhere bare on the frame or engine.This time you want to an,"Open" circuit eg there should be a high or infinite resistance.None of the coils from the stator should EVER go to ground/earth.

Note:If your Stator passes tests 2 and 3 but still has a low voltage at the battery whilst idling it may be a bad ground cable/Bad main fuse holder/Faulty battery.

If it has a High voltage at the battery whilst idling it could be a faulty Regulator/Rectifier unit.

One of the most common causes of Electrical problems on these bikes is the fact that even if it looks good the
The Main fuse golder is most likely over 25 years old.Change it!!!!!

Click here

This is a picture of the Transistor(G8) Ignition version Stator as used on the GL500s etc


Note:I have no factual evidence to prove that epoxy coated Stators last any longer than none coated ones.There are too many variables involved.Better if possible to get one from a known good supplier no matter how it's constructed.
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Location: Hull.Yorkshire.UK.2x1980 CX500ZABs:Citroen ZX TD(250,000 miles)

Re: Quick Stator Check/Charging Check

Postby mildhog » Wed Aug 13, 2008 12:38 pm

Making sure your electrical connectors are clean, especially the stator (3 yellow wire) connector, has been discussed on other forums. I have the "heads up" voltagemonitor DaveF(from Atlanta) reccommends: ... onitor.htm

Lately, after starting, I had to rev up higher to get it to turn green indicating proper charging. Even on the road, it indicated charging was marginal. Last night I disconnected the yellow wire connector and cleaned it with a pick and contact cleaner. Reassembled, fired her up and it was green at the lowest idle. Two things I took away from this: 1)Clean connections may prolong your stator and prevent electrical problems, and 2)A voltage monitor on board is a handy thing to have.

Keep 'em clean.
Arnie in VA
1982 GL500 Interstate
1983 GL650
Posts: 11
Joined: Mon Jul 28, 2008 5:05 pm
Location: Chesapeake, VA

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