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Discussion Starter · #1 ·
Hey all. So, I recently had my CDI controller fail. I did all the tests and received help from a fellow RC owner. It was the CDI. My question is I found on this site all the threads about failed CDI. It appears that most believe that something caused the failure of the CDI. I tested the stator and Rectifier/Regulator....those were both good. I replaced the R and R just in case. Now, it appears that the rear coil was suspect. So the question is...does anyone think that due to the location and how all the wiring is right next to each other (coil and the r and r) that voltage could have leaked and caused the failure? Since this happened I ordered new coils and caps...well the rear coil is now discontinued.....so I did the 600rr coil mod. So, second question... the bike feels like the spark is “snappier”... kinda like when I’ve put multiple spark discharge on a car (Think MSD)....I believe that the threads here say that from the CDI the factory coils get a 100v signal....where as the 600rr coils would get 12 volts when installed on a 600rr. That would increase my spark voltage on my RC....right. If any one can confirm or deny this I would appreciate it. Thanks.
 

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your reasoning is dead on. the 600rr are expecting a primary voltage of 12, but are getting a primary voltage of around 100. so your secondary voltages should be higher as well.


i don't really believe that this is going to change anything as the fuel will be ignited either way. but i do agree that the primary voltage is different.



i don't think your story about "voltage leaks" is valid though. it may sound nice to the ear but it's a nonsense use of terms.
 

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Discussion Starter · #3 ·
Thanks Wibbly. I recently purchased a secondary voltage tester and I will test the coils and see what the output is to the spark plug. Does anyone know what the 600rr secondary coil output voltage is?

As far as “voltage leak”, if the secondary spark plug coil wire (6k volts plus) is damaged (i.e. old and cracked) voltage will exit the insulation to the closet ground. I am a commercial electrician and I use a megger frequently on circuits to test Voltage “leak” and damaged wire. Since a megger works like a stun gun I didn’t want to put it through the coil. Since the Regulator/Rectifier has a ground wire on the output side (DC) I think it’s possible. Just wanted to know if anyone had a CDI failure and a rear coil failure similar to my problem. Again, I do not want to buy another CDI $$$$$$$.

Thanks again.
 

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If you had a short on the output of the ignition coil exactly nothing would happen. It's literally designed to short to ground. The impedance of the coil itself prevents any issues. All you'd lose is the spark at the plug.



If you had a short on the low side of the ignition coil it may overload the transistors in the cdi.


The rectifier is nowhere near the rear plug wire anyway. If you did have "leakage" it would just go to ground and end up at zero potential. All its voltage is dropped across the gap. It can't "zap" anything. If it could your spark plugs would destroy your bike.
 

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Discussion Starter · #5 ·
Thanks again wibbly. However, the connection for the input side Regulator/Rectifier (AC) is right next to the stock rear coil and doesn’t have a boot over the connector. The output side of the Regulator/Rectifier (DC) is right next to that and has a boot over the connection. Why does the DC side have a boot? Since you have tested my electrical knowledge (which I appreciate), I’m going to say that boot is to stop interference or “leakage”. Guess I’ll do some research on those boots.
 

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there are boots over connectors all over the bike. it's probably just to stop the connectors knocking together and making noise or wearing prematurely. it's certainly not to protect against "leakage" from the high side of the ignition coil that's located several inches away lol


coil by William Glancy, on Flickr
 

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Discussion Starter · #7 ·
Thanks for the visual. If you include a measurement you’ll see that distance is a few inches. And actually the AC side from the stator is actually closer than the DC side (with the boot). Since at 5000 rpm the AC voltage can be high as 80volts phase to phase ...I still believe that it possible that if the spark plug wire has degraded there is a potential for “leakage” that can cause damage to sensitive electronics (the CDI). Since no one can give an exact cause of the CDI failure why would you totally discount my theory? As a commercial industrial electrician I work with control cabinets that have a variety of voltages in one enclosure. I have personally repaired damaged to these systems when a damaged wire has “leaked” ... and sometimes you can see where the arc occured. That distance is more than the distance shown in your illustration. Making the repair easier. Sometimes it takes some trouble shooting to figure the same circumstances. Again, I thank you in regards to having to really think this all the way through. With my problem all of the components were ok except the rear coil and the CDI. So, to you Wibbly, do you have an answer or a theory as to how those components failed at the same time (approximately). Maybe you can enlighten me about something I haven’t thought of.
 

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Discussion Starter · #8 ·
Oh and I did a little research on the 600rr coils. Turns out there is a company called energycoil that makes improved coils for the 600rr and other bikes. They claim to increase the voltage on the secondary side of the coil which they also claim to increase horsepower. They didn’t give spec’s on they coils or a dynontest results. However on I believe a site like this for I think it was “Fireblades”...An individual was able to do a Dyno test and claimed to increase HP by 2. Although he said they factory coils were aged and maybe not working as new. My point is that a dyno test appears to have proven my theory that it’s possible to increase HP with higher voltage at the spark plug.
 

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Your "leak" would go straight to ground. The coil itself is bolted to the grounded subframe, and has a large ferrous core. Any issues there aren't going to jump past a bunch of grounds and into a +12v system several inches away.

80vac is a contact short. You could slice the insulation and it wouldn't short to anything. So I'm calling bs on the stator wiring theory.



I told you a low impedance on the low side of the coil could cause an overcurrent condition on the transistors in the cdi. Any circuit trouble on the output of the transistors can overload them. The cdi is fed by a 30 amp fuse so the transistors are not suitably protected.


I'm a master electrician as well, and own a variable speed drives and controllers company. You work isn't lost on me. I'm just telling you that your electronics didn't get "zapped" by the high side of the coil.


You are making pretty vague speculations here that I feel aren't based in truths.
 

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Discussion Starter · #10 ·
Again Wibbly thank you for your insight. I can tell your knowledge is excellent on these electronics. Ok so, the low impedance on the low side of the coil and you say that could cause the failure of the CDI transistors...right?.... I totally agree with what you say. How can I test (where and which terminals/connections) to verify I have the correct impedance so I KNOW that I have corrected the problem and won’t have another failure. I really do appreciate this banter! And again I don’t want a repeat of the CDI failure.
 

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i'd just check for ground faults on the input terminals of the coil. check the resistance vs a known good one (or manual specified resistance), and then check (with a megger set to 100v) for ground faults between the input terminals and the iron core. of course also check for ground faults in the wiring between the CDI and the coil.

it's not as simple to check impedance though i suppose you could use a source and measure current in the failed coil vs a known good one.


either way, the failure is the transistors. you have to think that the discharge current to the coil goes through the transistor (when called to fire by the ecm with a 5v gate pulse), at high rpm this can be a fairly rapidly occurring event. so anything that increases current through the circuit can damage the transistors. they're not exactly high current devices.
 

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Your "leak" would go straight to ground. The coil itself is bolted to the grounded subframe, and has a large ferrous core. Any issues there aren't going to jump past a bunch of grounds and into a +12v system several inches away.

80vac is a contact short. You could slice the insulation and it wouldn't short to anything. So I'm calling bs on the stator wiring theory.



I told you a low impedance on the low side of the coil could cause an overcurrent condition on the transistors in the cdi. Any circuit trouble on the output of the transistors can overload them. The cdi is fed by a 30 amp fuse so the transistors are not suitably protected.


I'm a master electrician as well, and own a variable speed drives and controllers company. You work isn't lost on me. I'm just telling you that your electronics didn't get "zapped" by the high side of the coil.


You are making pretty vague speculations here that I feel aren't based in truths.
I just wanted to know if you'd care to divulge the name of your company ? Did you mean VSD or VFD ? I'm a commercial A/C tech.
 

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VSD and VFD are used interchangeably. To an electrician it's a VFD, to a layman it's a VSD.

My company is called laser it automation. We automate oil wells using vfds, controllers, and our own licensed Scada system. I do all the setup, programming and tech support, and my partner takes care of sales.


We work mostly with yaskawa, ge danfoss, and Toshiba drives, though I know my way around most of them. Yaskawas are my favorite though.
 

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Discussion Starter · #15 ·
I’ll give a shout out to Wibbly as well! I’m off to New York to visit family , when I get back I’ll do some testing of the items that I can test. However, I believe that I found the source of the problem based on this thread. And since I live in California, when I get back I’ll also go take the RC for a nice road test🤪... thanks again for your insight.
 

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VSD and VFD are used interchangeably. To an electrician it's a VFD, to a layman it's a VSD.

My company is called laser it automation. We automate oil wells using vfds, controllers, and our own licensed Scada system. I do all the setup, programming and tech support, and my partner takes care of sales.


We work mostly with yaskawa, ge danfoss, and Toshiba drives, though I know my way around most of them. Yaskawas are my favorite though.
Variable Speed Drives vary voltage , Variable Frequency Drives vary pulse width.
 

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Variable Speed Drives vary voltage , Variable Frequency Drives vary pulse width.

no.... not quite.


a VSD just refers to a drive that changes the speed of a motor. if you are using a VSD in a dc application then it would vary voltage, yes. however a VSD in an AC application is a VFD. it's the same thing. VSD is just a name, it doesn't refer to anything specifically.


if you vary voltage on an AC motor it doesn't change the speed, it just changes the torque.


if you vary pulse widths on a VFD you are only changing voltage, this doesn't change speed either, only torque.



the output from a VFD is a PWM where the pulse width determines output voltage, and the rate at which the pulses widen, then narrow, then invert, then widen, then narrow, then invert is the frequency. for each positive and negative portion of the sinwave there are a number of pulses, starting very narrow and working wider until they narrow back down again, the widths of these pulses are determined by the commanded output voltage of the drive. higher voltage = wider pulses on average, though they still ramp up and down in width. each of these pulses is full bus voltage (in a single level drive). the inductive reactance of the motor windings smooth these pwms creating a sinusoidal current waveform in the motor. you can also use a reactor on the load side of the drive to create a sinusoidal current waveform. the carrier frequency determines how many of these pulses there are. the rate at which the pulses narrow and widen, then inverse determines the frequency and motor speed. the width of the pulses themselves only changes the voltage.


VFDs (and VSDs in AC applications) both vary frequency AND voltage to maintain constant torque in the motor. this can be done either by a fixed VF ratio (ie a 480v/60hz motor would be 8v/hz), or using vector control (open loop or flux vector using encoder feedback).
 

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In a DC drive you can either use pwm via transistors and Change pulse widths at your carrier frequency (led controllers do this too) to adjust DC voltage (assuming you have a DC input)

or you can use SCRs from an AC input and vary the firing angle on the gates to change DC voltage. SCRs need filtering circuits on the output due to unstable bus voltages.
 

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no.... not quite.
...
VFDs (and VSDs in AC applications) both vary frequency AND voltage to maintain constant torque in the motor. this can be done either by a fixed VF ratio (ie a 480v/60hz motor would be 8v/hz), or using vector control (open loop or flux vector using encoder feedback).
Now you're just showing off. :wink2:
 
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