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Discussion Starter #1
Hey so I was given a 1988 Polaris trailboss R/es. I got it running after cleaning the carb. So it was running but not very well. Seemed to have low power, so I thought about a air leak. I changed the crank seals and as I was trying to get the fly wheel off I accidentally touched the stator and it sparked a couple times. (I know I should have unplugged it or the battery for that matter). I got everything back together and Bamm no spark. I thought I had shot the stator so I bought a new one put it on as well as a new ignition coil. Still no spark. I dont know what else I could have messed up. CDI box I'm guessing. I was wanting some input before I start buying parts.
 

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I would like to know what in the stator had battery power to it when then stator generates AC voltage and there are no battery voltage wires anywhere near the stator?

If battery voltage was applied to an AC component, yes, it was probably damaged and needs replaced.

There are basically 3 parts to the ignition system - stator, CDI box and coil, but also included is the flywheel, wiring, spark plug, spark plug cap and reverse speed limiter module.

Since the battery is not involved, as long as the battery runs the starter motor, it is fine - start trouble shooting a loss of spark issue by unplugging the kill wire (black) from the CDI box - if still no spark and the stator and coil are new and working as designed, the only thing left is the spark plug cap, spark plug and wiring.
 

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Hmm how would it have sparked then?? Ive tried disconnecting the black wires. No luck there. I haven't done the reverse limiter yet, I'll do that next. I've tested the new stator is 122 witch the service manual says 120 the coil itself is good but the new coil cap has zero resistance that can't be right. The old cap gives the the right reading but it's rare I have to hold it in the right spot. It's that normal?
 

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The plug cap has a 5K resistor built into it - I presume you bought cheap Chinese 'fits' parts? It may fit and it might work, but it's up to the mechanic working on it to verify things.

Only one black wire is key - the one going to the CDI box - all the other black wires are tied into it - disconnect the black wire at the CDI box and there is no way to stop the running engine other than removing air, fuel, spark or compression.

A zero resistance plug cap will not prevent spark, but will change timing and spark intensity. No, what you describe is not normal.

As to the spark at the stator when removing the flywheel - check each wire for battery voltage both key on and off to determine incorrect wiring connections - should not be any battery voltage to the stator or CDI connections.
 

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Discussion Starter #5
I checked for voltage goining to the stator and with key on and off the two yellow wires get volts one gets 10 and the other gets 12. I also have a black wire that doesn't go to the cdi box I don't know where it comes from it get 1 volt?? Are these readings normal
 

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I did some more testing and I'm getting 3000mm volt out of the cdi is that enough to create spark. Also my primary side of my ignition coil is resistance is supposed to be between .3 and .5 but when I test it it starts at 4 and goes down to 1 is that how it's supposed to be?
 

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The yellow and black wires should not have voltage on them - the yellow wires go to the rec/reg to charge the battery

The black wires are all kill wires and none should have voltage - black goes to the key switch, handlebar switch and the reverse speed limiter. One yel wire goes to the speed limiter module (plugs into the module white wire) - if there is voltage on the yel wires, then the blk wire could get voltage from the speed limit module. Unplug the yel wire from the rev limit module and see if the voltage on the black wire disappears.

Unplug the yel wires from the rec/reg to get rid of the voltage on them.

You need a peak voltage tester to troubleshoot the ignition system - typically the pulse coil will generate 3 to 5 PEAK volts, the charge coil typically generates about 30 to 45 PEAK volts - the charge coil charges the capacitor in the CDI box to about 100 volts - when the pulse coil tells the CDI unit to fire the spark plug, a spike of about 100 PEAK volts is sent to the coil and the coil transforms it to a 30 to 40,000 PEAK volt spike to fire the spark plug.

I hope you are finding this helpful

139885
 

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Discussion Starter #8
I have taken the yel wire from the rec/reg that one still gets power but it seems all yellow wires and a power are in one harness to go to the rec/reg . Kinda makes sense according the diagram you sent me.
I also dont get a resistance reading on my cdi unless I hold it to the tab with my finger
 

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Are those 5 wires all junction-ed together?
 

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Man - that is messed up - I'm trying to figure out what the Polaris engineers were thinking on that system - I have a degree in electronics and it looks all wrong, but I didn't design it and I don't know whats inside the boxes.

You can't test the CDI unit with an ohm meter - I gotta study this a bit before I can make a suggestion - it may be the wiring diagram was drawn incorrectly.
 

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I think this is the problem: the yellow/red wire is supposed to be connected to the red wire and the red wire goes to the battery, key switch and regulator - that makes the red wire HOT which when plugged into the y/r makes both the y/r and y wires hot also.

The yellow wire from the stator goes to the regulator and the reverse speed limiter only.

Take that junction apart and connect red to red/yel - connect yel to yel - the other wire (black?) needs to be traced the see where it terminates.
 

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If I get a chance today I'll take a look at my 87 trail boss 250 r/es and see if I have something similar


Sent from my iPhone using Tapatalk
 

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The black wire is the kill wire - look at the diagram; it goes from the key switch to the handlebar switch - it goes from there to the CDI unit and the reverse speed limiter - when the switches close, it connects the black wire to ground (blk/wht wire) and kills the spark - in reverse, the yellow wire provides a signal that the limiter module reads and at a preset value (engine RPM) the green wire provides a path through the neutral light to ground (brn wire) which at the preset RPM, the module connects the black wire to the green wire momentarily killing the spark to limit the engine speed - pushing the override button removes the path to ground and engine speed is then unaffected.
 

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Discussion Starter #18
One thing shouldn't my cdi box have some resistance. I tried checking resistance all I get is the OL on my multimeter but if I hold the prong down with my finger then I get resistance in the thousands, without my finger I get nothing.
 

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Discussion Starter #19
Since I've isolated it to just the cdi shouldn't I get spark with the yellow wires not plugged in since that for charging the battery.
 

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I would say yes, but now I'm going to confuse the hell out you - the CDI box is connected to the battery.

The CDI box is grounded and ground is connected to the neg side of the battery. Now this in itself is not out of the norm, but the fact that electricity flows from neg to pos make an astronomical difference to the components. Years ago, positive ground systems were common (my 63 Ford was a positive ground and my 72 Triumph motorcycle is positive ground). Whether it is pos or neg ground is determined by the charging systems components. Now the 63 Ford could have been either pos or neg ground as it had a DC generator charging system - all that was necessary to change the ground was to connect the battery in reverse and polarize the generator and it was fine with that, but the heater motor would run backwards, the radio would not work and the electrical gauges would all read zero except the ammeter - the am meter would show discharge when charging and show charging when discharging.

The Triumph motorcycle was much easier the change as it used an alternator for charging. Just connect the diodes in reverse, swap battery wires and install a correct polarity voltage regulator.

The CDI unit should show continuity on a or some terminals, but polarity and values are not published as continuity is not an accurate test. When you shorted the stator and got an arc, it would not affect the ignition unless you shorted the battery charging coils to the CDI charging coil - shorting the two coils together would send battery voltage to the AC CDI and burn it out.

Now as far as reading a resistance when holding the meter leads 'real tight' to the terminal, that is normal also - you were probably reading your body's resistance. Try holding the meter leads between your thumb and a finger of each hand and squeeze real tight - get a reading? Try wetting your fingers and read the resistance. Now put some salt on your wet fingers and read the resistance. It keeps dropping - right? The moisture in your skin aids the conduction of a current from one meter lead to the other and adding an impurity like sodium (salt) makes that conduction even better. A person with dry calloused hands is not as sensitive to an electrical shock as a person with soft moist hands. Some women may get shocked from a 9 volt battery while most men may not get shocked from a 24 volt battery, but AC voltage is more easily felt than DC voltage. If you get a DC shock it is more painful than an AC shock.

My son is an electrician by trade and he has found out he can handle 120 AC wiring without getting shocked, but his mom can be shocked with 24 volts AC. His mom was complaining about getting shocked whenever she pushed a doorbell button - he didn't believe it, but when he started testing doorbell buttons, he found out many had 24 volts AC on the metal ring around the plastic button. While he couldn't feel it, he could measure it, but his mom with soft moist hands could feel it. She said it wasn't painful, but she knew she would feel it before she pushed the button.

Anyway - there is no test for the CDI unit other than replacing it with a known good unit.
 
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