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83 Honda CM250C
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Discussion Starter · #1 ·
So as the title says I am changing alternators. I have an 83 cm250c. I rewired the entire bike head to toe. not the first bike i have worked on but I was also a diagnostics car mechanic for over 10 years so i know what I am doing lol. anyways the alternator crapped out on my bike. i want to buy a new one but for $200 its just not in the cards right now. i did however get a free alternator for a (known working) 2000 honda rebel. This one has one less wire coming from it then the original. is there anyway to make this work or am I S.O.L.?
on a side note i was able to rebuild my starter clutch with springs i purchased from harbor frieght in a kit for like $5.00 just an F.Y.I.

PS. bike was running and just not charging. i plugged the new one in just to see but i didnt even get spark. i am confuse because the alternator shouldnt have anything to do with spark, or are bikes that much different then cars? let me know. thank you
 

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1987 CMX250C AC
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are you changing the entire stator?
Have you tried replacing voltage regulator?

there are 3 functions to stator and flywheel combination..
3 phase AC charging current sent to rectifier/regulator which are the three yellow circuits..

A Red/Black AC circuit supplying 100-400vac to CDI as well as a ground

than there is separate pulse generator coil with Blue/Yellow and Green/White wires located externally from flywheel whose magnet triggers pulse causing CDI to fire the spark plug coils..

the Rebel ignition most resembles magneto type system used on most reciprocating aircraft engines.

btw it has been found the 2nd generation 96-2016 Rebel stator is larger than 85-87 Rebel so your 2000 replacement may not fit inside the CM250 flywheel.
 

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83 Honda CM250C
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Discussion Starter · #3 ·
are you changing the entire stator?
Have you tried replacing voltage regulator?

there are 3 functions to stator and flywheel combination..
3 phase AC charging current sent to rectifier/regulator which are the three yellow circuits..

A Red/Black AC circuit supplying 100-400vac to CDI as well as a ground

than there is separate pulse generator coil with Blue/Yellow and Green/White wires located externally from flywheel whose magnet triggers pulse causing CDI to fire the spark plug coils..

the Rebel ignition most resembles magneto type system used on most reciprocating aircraft engines.

btw it has been found the 2nd generation 96-2016 Rebel stator is larger than 85-87 Rebel so your 2000 replacement may not fit inside the CM250 flywheel.
voltage reg. is brand new. as is the pulse generator coil. as for the magnets i was removing the flywheel and as i went to unscrew them they were shattered to bits. previous owner couldnt get the flywheel off so he hit it with a hammer... i was able to get new, thinner magnets in there with the same force pull as the previous original magnets.
the 3 yellow wires shouldnt matter which pin they are in, correct (differentiating between the years and models)? as for the red/black wire should serve the purpose that the old alternators white and blue wires were used for. in the wire diagram it shows that the white wire and blue wire are connected in the alternator only seperated with a resister. with that being said, should i be able to just connect the red/ black wire to a white and blue wire granted i put a resister in there before the cdi?
 

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83 Honda CM250C
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Discussion Starter · #4 ·
voltage reg. is brand new. as is the pulse generator coil. as for the magnets i was removing the flywheel and as i went to unscrew them they were shattered to bits. previous owner couldnt get the flywheel off so he hit it with a hammer...
unless its a bad idea all in all and i should just wait to get the oem for it instead of trying to save a buck
 

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85 CMX 250C, 82 GW Remember that you are invisible, treat all others accordingly. Avoids Road RAGE!
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I think most of us are just overwhelmed by how many things could be wrong. I'm just trying to think about where to start. I've never heard of anybody replacing the magnets in the flywheel, have you done that before? I think it would be better just to replace the whole flywheel.
 

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Discussion Starter · #6 ·
I don't have the money to spend on a new flywheel nor will i anytime in the relatively near future. I have not done it before though i am pretty sure it will work, but what's a better time to see if it could work then now. Like i said though they are just smaller (thinner) magnets with the same force pull as the others were, but my issue is with the electrical portion of it for now, if it can't be done then the bike(my only means of transportation at the moment) is doomed to stay put until i get out of the financial dilemma i am in right now
 

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85 CMX 250C, 82 GW Remember that you are invisible, treat all others accordingly. Avoids Road RAGE!
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Most of us have been there between a rock and a hard place before when it comes to money and transportation and taking care of our needs. A lot of understanding about that one.
I'll let the skilled people give you answers. I don't pretend to be as skilled as many of those that reply.
 
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Discussion Starter · #8 ·
Most of us have been there between a rock and a hard place before when it comes to money and transportation and taking care of our needs. A lot of understanding about that one.
I'll let the skilled people give you answers. I don't pretend to be as skilled as many of those that reply.
Okie dokie. Thanks for the response though
 

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1987 CMX250C AC
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I've pondered about the placement of yellow charge coil wires in the past whether phasing is important or not..
honestly I'm not familiar with the 8 wire CDI operation of CM250T i see in wiring diagram..
I see Blue, Green, White, Pink, and Light Blue circuits from stator.
No indication is made which does what in the diagram I have.. nor do I see resistor between Blue and White..
Can you post an image or scan of your wire diagram?
This is a cutout from the CM250T charge/ignition wiring I have to go by. As you can see the alternator internal windings wiring leaves a lot to be desired..

Rectangle Font Parallel Drawing Diagram


this is what I have to work off of for Rebel alternator

Rectangle Font Slope Line Schematic
 

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1987 CMX250C AC
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yea I just picked up that CM250C wiring diagram elsewhere while looking up the CM250 CDI.. I found most were 7 wire rather than in the 8 wire wiring diagram I had..

your Blue and White wires are not interconnected with a resistor, that is a winding and appears that CDI is supplied with a 2 phase charge as flywheel magnets pass over the two separate windings..

No dumb questions here only uninformed do it yourselfers searching for answers. i'm not familiar with this setup doubt you can make Rebel stator work even if your flywheel magnet replacement is working..

Schematic Font Line Parallel Rectangle
 

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83 Honda CM250C
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Discussion Starter · #14 ·
Thanks for all your help. You seem to know your way around a bike lol. Im going to mess with it and see what the turn out is. I will post what happens to keep you updated. I will post pictures as well so you can see what's been done
 

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1987 CMX250C AC
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2,466 Posts
Does this CM250C stator look like yours?
I find at least one used 31120KB4005 CM250C stator on eBay

It differs from 1st generation Rebel stator in that it has 2 larger windings opposite to one another to power CDI..

Machine Rim Nickel Auto part Automotive wheel system


1st gen 85-87 Rebel only has One large winding powering CDI
The 2nd gen 96-2016 stator has two windings to power CDI placed beside each other.. The 2nd gen stator is slightly larger in diameter and makes physical contact with 1st gen flywheel which isn't good..

Engineering Automotive design Motor vehicle Auto part Machine


you might get spark by connecting just the Blue or White lead to Red/Black stator wiring.. I wouldn't count on it though.. would also be concerned about damaging a good CDI
 

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83 Honda CM250C
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Discussion Starter · #16 ·
Does this CM250C stator look like yours?
I find at least one used 31120KB4005 CM250C stator on eBay

It differs from 1st generation Rebel stator in that it has 2 larger windings opposite to one another to power CDI..

View attachment 111496

1st gen 85-87 Rebel only has One large winding powering CDI
The 2nd gen 96-2016 stator has two windings to power CDI placed beside each other.. The 2nd gen stator is slightly larger in diameter and makes physical contact with 1st gen flywheel which isn't good..

View attachment 111497

you might get spark by connecting just the Blue or White lead to Red/Black stator wiring.. I wouldn't count on it though.. would also be concerned about damaging a good CDI
That's exactly what i was looking for. Yes i do have the second gen stator but it does not make contact with the flywheel because of the magnet mod i did. As for the wiring. So either white OR blue correct? Not both connected to the red black? The regulator im only half concerned about. It's still under warranty and i know they'll accept it if i do fry it. Thanks again. Right now im cleaning my garage, something I've held off for a while. But when i have a minute or two ill tinker with it and let you know
 

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83 Honda CM250C
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Discussion Starter · #17 ·
Does this CM250C stator look like yours?
I find at least one used 31120KB4005 CM250C stator on eBay

It differs from 1st generation Rebel stator in that it has 2 larger windings opposite to one another to power CDI..

View attachment 111496

1st gen 85-87 Rebel only has One large winding powering CDI
The 2nd gen 96-2016 stator has two windings to power CDI placed beside each other.. The 2nd gen stator is slightly larger in diameter and makes physical contact with 1st gen flywheel which isn't good..

View attachment 111497

you might get spark by connecting just the Blue or White lead to Red/Black stator wiring.. I wouldn't count on it though.. would also be concerned about damaging a good CDI
I forgot to answer your question. Yes the original stator that was in the bike was the one you found on ebay. But for future reference do you know a good reliable rebuilder or supplier?
 

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1987 CMX250C AC
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No I don't know of stator rebuilder though I came across this one in the past
Ricky Stator - Stator Rewinds or
I've seen others listed on internet searches

several 1st generation owners have looked for replacement stators when theirs gave up the ghost, I know of no one who had theirs rebuilt..

Not uncommon to need replacement of obsolete stator..
the Honda Twins forum has DIY threads
as well as threads about dual windings powering CDI
Check Recommended Reading threads listed at bottom of pages

I think I would connect Red/Black to a single circuit, Blue first than try White.
 

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83 Honda CM250C
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Discussion Starter · #19 ·
No I don't know of stator rebuilder though I came across this one in the past
Ricky Stator - Stator Rewinds or
I've seen others listed on internet searches

several 1st generation owners have looked for replacement stators when theirs gave up the ghost, I know of no one who had theirs rebuilt..

Not uncommon to need replacement of obsolete stator..
the Honda Twins forum has DIY threads
as well as threads about dual windings powering CDI
Check Recommended Reading threads listed at bottom of pages

I think I would connect Red/Black to a single circuit, Blue first than try White.
Thanks a bunch. I didn't have a chance to get to it today but i did look at wiring diagram comparisons. Technically if i change the cdi as well then there shouldn't be a single problem with wiring at that point. It would eliminate the blue and white wires
 

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1987 CMX250C AC
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yes a 2nd gen CDI would solve the wiring problem..

I've been using this 2nd gen aftermarket version on 87 Rebel since 2017

you can read writeup of adaptation to 1st gen

the ground and side stand safety interlock can be connected together
Light Line Font Auto part Rectangle
 
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