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battery disconnected stops running

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IDK< but you can start and run the ski if the rectifiers is disconnected.....although it will stay running until the battery is drained. Probably within 20-45 minutes depending on the battery strength to begin with.
 
I seriously doubt it would keep running. Im going to guess you could seriously damage your MPEM as well. Why would you want to do this?
 
I don't think it will keep running, actually i'd guess that it would just die immediately but I wouldn't bet more than $5 on it, and i've certainly never tried.

I can't imagine why you would do it unless maybe you had two ski's 20 miles from the ramp, and one ski had a completely dead battery ?
I'm grasping at straws here.
 
i had a battery die from vibration on the water (walmart nEverStart) and it killed the skit straight away. the voltage popped right back but it had no power, even moving the vts would drop voltage enough to kill the MPEM. had to get towed in, replaced the battery and all was well again.
 
I tried it on both of my 98 gtx and they died. Just going on how my dirt bikes and four wheelers are wired. I guess it's in the mpem. I'm assuming it's magneto -rectifier-battery-coil-?
 
Please don't do this test on these skis, it will damage parts!

It will also tell you nothing. a MPEM is a $500+ piece of computer in these skis.

Do not jump start them and do not disconnect the battery while it's running.

Please start a new thread with the issue you are having and we can help you try to fix it...
 
i agree thats its a gad idea to test it like that.

although the computer's aren't quite $500, more like $220, but still, you have nothing to gain by testing that.
 
Who has a schematic of the epem. One of the four wires of cdi is 5 amp fuse from what rectifier or battery?
 
I know it's not one of your usual grey fuel or pop off pressure threads so your stumped
What is your issue? He's trying to help.
Just because it may have come across in a bad way to you, doesn't mean he meant anything bad by it.

If I were you, I wouldn't want to be killing my MPEM. If that's what you desire, power to you man.
 
I tried it on both of my 98 gtx and they died. Just going on how my dirt bikes and four wheelers are wired. I guess it's in the mpem. I'm assuming it's magneto -rectifier-battery-coil-?

Have you started them back up yet after you disconnected the battery while running?
 
You need the battery in the circuit to smooth out the voltage ripples, else the MPEM will likely stop working. I wouldn't do this "test" on purpose on the premise the (fragile) MPEM might be damaged (why risk it?) or any vehicle for that matter. Read the service manuals on about anything and it will explain the several reasons, or take an high school basic electronics class.
 
Ok my high school electronics class tells me that the rectifier sends 12 volts to the epem through the 15amp fuse from the 3 phrase generator (three wires) I believe the white is for index. Is that what you get too? Between the cdi and mpem one of the four wires is 5 amp fuse. One ignition impulse. Timing advance and tach I'm sure you already knew this. So where does the battery tie into this being charged through red wire?
 
Ok my high school electronics class tells me that the rectifier sends 12 volts to the epem through the 15amp fuse from the 3 phrase generator (three wires) I believe the white is for index. Is that what you get too? Between the cdi and mpem one of the four wires is 5 amp fuse. One ignition impulse. Timing advance and tach I'm sure you already knew this. So where does the battery tie into this being charged through red wire?

The average output voltage of the rr is greater than the battery voltage while the stator is being excited, current flows into the battery as a result of this slightly higher average voltage as the SCR's inside the rr switch on.

Grab an oscilloscope and hang it on the system, I would expect absent the battery to sink the current and thus limit (or, "condition") the voltage spikes, you will probably observe 80 volt p-p rms or more peak voltage spikes dancing on the MPEM power feed as the rr SCR's turn on.

What is the output voltage in AC of the unloaded 3-phase stator?
 
I just meant as a full converter. I'm surprised they use SCR's instead of diodes. Makes sense they use a zener to regulate the output at a reasonable cost.
 
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