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Discussion Starter · #1 ·
I recently purchased a 1979 CX500 for $100, needed a triple bypass, which has been done.

When I bought it the previous owner said it wasn't charging, which I confirmed after I got it running once, before I did the bypass.

It was very difficult to get it running then, but I did manage to get it fired up (somehow) to test the Voltage output. THe three yellow wires coming from the stator where all shorted to ground.



So I did the triple bypass, put in a second hand stator that I got off ebay - this stator was a fresh, unused rewind from Custom rewind, never used since rewound.

The stator resistance check was perfect when I had it mounted in the rear case, before assembling the engine and putting it back togeather. FWIW, now I just checked it again, bike fully assembled, and all the resistance checks are within spec except for the last one (5/9) which is the "Source Coil Low Speed". it should be in the range 315-385, I'm getting 190 ohms. Don't know if that is related to my "won't start issue now though. The three yellow wires test good, none have continuity to ground, and they all have continuity to each other.



I did get it to run once after reassembly from the triple bypass engine R&R, but it was not charging which I suspect is due to a fried voltage regulator, now that it has a good stator. It was very hard starting like before, and it wouldn't idle under 1500 rpm. I took it down the road a bit and it ran really good above about 5 or 6k right to redline, but below that it was a bit doggy. It ran, but it was lacking any power below 5 or 6K, Idle was ok, as long as it was set to 1500-1600. When I shut it off after that ride, I have not been able to get it to fire now, not even a pop or spit.



I took apart the carbs and cleaned them, they didn't look all that bad inside, and blew out all the air and fuel passages and everything seems to be fine. Also, if I try to start by spraying starting fluid in the carbs, I still don't get any fire. Take the plugs out and crank it, I get blue spark, although it may be a little weak. I don't know what to expect visually on these things.





There are obvious indications of wiring overheating near the two red connectors, down near the starter solenoid - red and red/white wires and the two associated plugs, one attached to the regulator, the other to the fuse holder and battery. I have replaced/repaired those wires. At some point in time it looks like there was a short to get these wires melting, but no short now.



I just did the CDI test that Reg in Bristol describes here:

CDI test in other thread



I get about 25 volts initially when I start cranking and it drops off to about 3 or 4V, both sides the pink and yellow leads off the CDI box. He says I should see 150-200V??

If that's the case, is my CDI Box shot?





The way I see it now, I need a voltage regulator and a CDI box. If anyone has any additional tests I should run to help verify, or other input, I would greatly appreciate it. Thanks .



I wish I had a spare CDI box to try....that would make it a lot easier.



Dave
 

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Dave

"25 volts initially when I start cranking and it drops off to about 3 or 4V"

That would concern me as it doesnt look good at all.

But.

The CDI output test is an "all other things being equal" type test and presupposes a good stator.

the 150-200Volts DC figures were taken from well running bikes.



Your 5-9 reading of 190 is quite a way off the spec of 387-473

If the low speed coils are up the swanee, yer screwed as the WW Fix is NFG in this instance

All the low and high speed coils do is power the CDI so low power, low readings.

I'd suggest another careful check of all the stator resistances including the yellow wires and all connectors before continuing and making any assumptions
 

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Discussion Starter · #3 ·
Dave

"25 volts initially when I start cranking and it drops off to about 3 or 4V"

That would concern me as it doesnt look good at all.

But.

The CDI output test is an "all other things being equal" type test and presupposes a good stator.

the 150-200Volts DC figures were taken from well running bikes.



Your 5-9 reading of 190 is quite a way off the spec of 387-473

If the low speed coils are up the swanee, yer screwed as the WW Fix is NFG in this instance

All the low and high speed coils do is power the CDI so low power, low readings.

I'd suggest another careful check of all the stator resistances including the yellow wires and all connectors before continuing and making any assumptions




Thanks for the quick reply Reg. Checked all the conectors, don't see any problems. Resistance for 5-9 is 200 now, maybe because the temp is a little cooler out?





Sorry, but more questions:



So are the 'source coils' part of the Pulser stator or are they integral with the AC generator stator? I bet they are integral.



Is there a resistance check for the three yellow stator wires? FS manual just states check for short to ground and that all leads have continuity with each other.



Better yet, If I got a ignitech, would that eliminate the need for all these crazy low/high CDI coils? I'm all for making it simpler.

I think I read on here that it does, just not sure.
 

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Dave

the CDi stator is 2 in 1 affair

its has 14 windings which supply 3 phase power to the rectifer/batterey etc

and two bigger diametrically opposed windings which supply AC power to the CDI box

these are the buggers that give the CX most of its ignition problems



The R & L pulsers which send trigger pulses to the CDI are mounted inside the rear cover

and seldom fail

( just as well as the ignitech relies on these)



the advance coisl are the smaller windings at the very back of the rear cover

these can drop out and affect performance as well.

I dont think you can buy them and while rewinding isnt impossible it would be

a damn tricky business due to how they are assembled and spot welded together.

many people use Ignitechs now

It a DC CDI and take power from the battery unlike the original AC CDI

the CDI piower coils are longer needed, neither are the advance coils

this means its possible to use the G8 type stator which has higher output

(250) as used on the later TI bikes.





The three yellows which carry the power from the stator to the rectifier

are easy to test as they should be in one of two states

Very low:

1 ohm between any two yellows

Very high:

megaohms between any yellow and ground

anything in between is suspect

Good clean connections in the 3 way plug is important as they've been known

to get hot and start to burn out which can adversely affect the Stator and

lead to early failure.

This appies to both CDI and TI bikes BTW



I have a TI motor in my bike and dont miss all the damn flaky CDI stuff

had I a CDI motor I'd be selling a kidney for an Ignitech or trying to find a cheaper

alternative.

I bet some joint in the far east could knock em out for half the price



Theres a rumour that before his dismissal for conduct unbecoming and excessive drunkeness,

a previous manager of a related UK club started taking an Ignitech apart

before his suspension.

Such corrupt and underhand practises are quiet rightly frowned on by the

current committee and proletariat I hear.




I think he was one of those inquisitive types who like to take stuff apart to see how things work
 

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Discussion Starter · #5 ·
Reg, thanks for your excellent reply, I think I have the jist of the stock system now. I found and purchased an ignitech, a guy had it new never used it from the last group buy, so I think that should solve my issues. You got me on the right path with the diagnosis, thanks. I've got a voltage Regulator coming also, hope that cures my no-charge ills with the rewound stator, as it tests fine.

I think the previous owner hooked something up wrong or shorted something and fried all the electrical components (stator/CDI/regulator), by the looks of wiring I mentioned previously.
 

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I have a TI motor in my bike and dont miss all the damn flaky CDI stuff

had I a CDI motor I'd be selling a kidney for an Ignitech or trying to find a cheaper

alternative.

I bet some joint in the far east could knock em out for half the price



Theres a rumour that before his dismissal for conduct unbecoming and excessive drunkeness,

a previous manager of a related UK club started taking an Ignitech apart

before his suspension.

Such corrupt and underhand practises are quiet rightly frowned on by the

current committee and proletariat I hear.




I think he was one of those inquisitive types who like to take stuff apart to see how things work


'ow much for the schematic ?
 

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Discussion Starter · #7 ·
Well I installed the Ignitech and a good, used VR and the old girl fired right up!!!!!!!

She's charging, and sparking at the right time now!!

Took her for a ride and I was really surprised at how well she runs. That Ignitech is the ticket.



Thanks again Reg in Bristol for all the help.
 
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