Maybe a higher wattage pot, to be better able to handle the power and dissipate the heat. The Russian circuit used what looked like a wirewound pot.
Roll Your Own CDI
- Thread starter rohmell
- Start date
Certainly looks that way. A higher wattage pot would be one solution.
Looking at the HT CDI, one wonders if the same problems occur.... I mean it contains a circuit (of some description), a coil and its small size indicates that it does not have the problem of having to dissipate the apparent heat issues associated with the circuit under discussion. To get rid of such a significant amount of energy from a seemingly limited supply does seem a bit wasteful and could be put to better use somehow.
On that basis, you have to agree the standard cdi is a very good design, despite its limitations.
Looking at the HT CDI, one wonders if the same problems occur.... I mean it contains a circuit (of some description), a coil and its small size indicates that it does not have the problem of having to dissipate the apparent heat issues associated with the circuit under discussion. To get rid of such a significant amount of energy from a seemingly limited supply does seem a bit wasteful and could be put to better use somehow.
On that basis, you have to agree the standard cdi is a very good design, despite its limitations.
OK. replaced the 100 ohm pot, 33 ohm resistor,and wired the diode directly to the pot.
Exact same result. Sustituted 1W 100 ohm resitors either side of the gate and only one got hot. Added another 100 ohm resistor and the circuit ran, but the resistors were very hot.
Sustituted 1k5 1/4 W resistors and the circuit ran beautifully.No heat and constant steady spark at 50VAC 50 HZ input.
Tried a 5 k pot and the circuit did not run and thats where I had to leave it.
According to my readings, the circuit draws 0.1 A at 50 V. This equates to a power consumption of 5 W.(This accounts for the heat in 1 W resistors). Also, I get around 25VDC across the diode. Far more than the 0.7 indicated earlier.
I'm sure that I have not wired this circuit incorrectly; if i had surely it would not run.
Any ideas?
Exact same result. Sustituted 1W 100 ohm resitors either side of the gate and only one got hot. Added another 100 ohm resistor and the circuit ran, but the resistors were very hot.
Sustituted 1k5 1/4 W resistors and the circuit ran beautifully.No heat and constant steady spark at 50VAC 50 HZ input.
Tried a 5 k pot and the circuit did not run and thats where I had to leave it.
According to my readings, the circuit draws 0.1 A at 50 V. This equates to a power consumption of 5 W.(This accounts for the heat in 1 W resistors). Also, I get around 25VDC across the diode. Far more than the 0.7 indicated earlier.
I'm sure that I have not wired this circuit incorrectly; if i had surely it would not run.
Any ideas?
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I don't understand why it is getting hot, since it is the same circuit as this one, except for a pot substituted for the fixed resistors, and I have used 1/2 watt resistors in the ones that I have built:
It would seem that if you use a pot and set it to simulate the fixed resistors' values, it would perform the same.
My feeling is that the diode that is across the resistors is bad, and you are not developing the 0.6-0.7 VDC across the resistor network.
It would seem that if you use a pot and set it to simulate the fixed resistors' values, it would perform the same.
My feeling is that the diode that is across the resistors is bad, and you are not developing the 0.6-0.7 VDC across the resistor network.
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Hey guys. It's been a while... I've been busy with moving and getting situated. I got my simple cdi built and working, and wow, it seems like i've missed a lot since i was on here...i'm excited to get a few more rides in before this crappy western pennsylvania weather takes over for the next 5-6 months. thanks again for all of the knowledge, lessons-learned, advice, and help! without you guys, i would just have a pile of parts collecting dust, spiderwebs, and stinkbugs...
The KZ80 CDI box/adjustable timing magnet set up seems to be the hot set up, plenty of juice.
The one thing i dont like is its kinda clunky looking.
Any one experimenting with twin plug heads?
FR
The one thing i dont like is its kinda clunky looking.
Any one experimenting with twin plug heads?
FR
Got my CDI working today 
The coil i'm using is one from a Mercedes S class
http://motorbicycling.com/attachments/f50/39494d1313979859-roll-your-own-cdi-p8220031.jpg
http://motorbicycling.com/attachments/f50/39496d1313981011-roll-your-own-cdi-p8220033.jpg
bikeignition - YouTube
The coil i'm using is one from a Mercedes S class
http://motorbicycling.com/attachments/f50/39494d1313979859-roll-your-own-cdi-p8220031.jpg
http://motorbicycling.com/attachments/f50/39496d1313981011-roll-your-own-cdi-p8220033.jpg
bikeignition - YouTube
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So Rohmell,
On this test circuit you have shown us, what minimum ma should that trans be? I have no knowledge of such things and defer to those in the know. Also, would I want to add a switch to see multiple sparks? Or does this unit fire indiscriminately when constant power is applied? Thank you for all the patience you have in putting up with us novices <G>. Building my second / backup CDI unit right now and might as well get the trans for testing while I am at it.
On this test circuit you have shown us, what minimum ma should that trans be? I have no knowledge of such things and defer to those in the know. Also, would I want to add a switch to see multiple sparks? Or does this unit fire indiscriminately when constant power is applied? Thank you for all the patience you have in putting up with us novices <G>. Building my second / backup CDI unit right now and might as well get the trans for testing while I am at it.
Just to be on the safe side, 500 mA should be the minimum current rating.
While plugged in, it will continuously fire the CDI, since the output of the transformer is AC, same as the magneto.
(60 Hz cycles per second * 60 = 3600 cycles per minute= 3600 cpm = rpm)
So essentially it will simulate an engine firing at 3600 RPM.
Nice Pics and video!Got my CDI working today
The coil i'm using is one from a Mercedes S class
http://motorbicycling.com/attachments/f50/39494d1313979859-roll-your-own-cdi-p8220031.jpg
http://motorbicycling.com/attachments/f50/39496d1313981011-roll-your-own-cdi-p8220033.jpg
bikeignition - YouTube
thankyou.
today i'm getting rid of the soap container and making it properly.
I think it's awesome how i managed to get the ignition coil mounted
I blew an intake gasket today
but the bike runs really smoothe and revs higher now.limiter for my china girl
can someone tell me can i wire this kierrosten rajoitin rev limiter to my china girls factory cdi.
it supose to wire so that the limiters red wire goes to cdi`s positive wire and the black wire goes to ground. the red wire of the limiter should be wired to pickup wire but china girl doesnt have it. would it work if i dissasemble my cdi box and hook the red wire to the coils positive and the black wire to ground.
or i have to just build simple cdi and put the limiter to it.
can someone tell me can i wire this kierrosten rajoitin rev limiter to my china girls factory cdi.
it supose to wire so that the limiters red wire goes to cdi`s positive wire and the black wire goes to ground. the red wire of the limiter should be wired to pickup wire but china girl doesnt have it. would it work if i dissasemble my cdi box and hook the red wire to the coils positive and the black wire to ground.
or i have to just build simple cdi and put the limiter to it.
Re: limiter for my china girl
Avaa se ja ottaa kuvan sisukset, jotta voimme nähdä sen toiminta.
If you build the Simple CDI, using a large value for the output capacitor will act as a rev limiter.
Jos rakentaa Simple CDI, käyttäen suurta arvoa lähtö kondensaattori toimii rev. rajoitin.
Open it up and take a picture of the insides, so we can see its function.
Avaa se ja ottaa kuvan sisukset, jotta voimme nähdä sen toiminta.
If you build the Simple CDI, using a large value for the output capacitor will act as a rev limiter.
Jos rakentaa Simple CDI, käyttäen suurta arvoa lähtö kondensaattori toimii rev. rajoitin.
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well i made a new CDI today. but i get no spark for some reason
will troubleshoot.
Here's a quick video i made of my progress.
bikeignition2.wmv - YouTube
see attached pics for the assembly.
Once i get the kinks out i'll be happy to make one for anyone who is sick of the tiny "made in china die in 2 weeks cdi's"
will troubleshoot.
Here's a quick video i made of my progress.
bikeignition2.wmv - YouTube
see attached pics for the assembly.
Once i get the kinks out i'll be happy to make one for anyone who is sick of the tiny "made in china die in 2 weeks cdi's"
Attachments
ok after the 'new' cdi i made before had a faulty from factory SCR i redesigned the layout a bit and came up with the picture below.
What do you guys think ? I tested it just before making this post and i get spark
edit: looks much cleaner in the box, however this cdi now doesn't have the hi/low spark option. I'll be able to add it in later though.
What do you guys think ? I tested it just before making this post and i get spark
edit: looks much cleaner in the box, however this cdi now doesn't have the hi/low spark option. I'll be able to add it in later though.
Attachments
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Re: limiter for my china girl
yeah but i want rev limiter with on off switch so i can put the limiter on only if police want to test my bike if it runs too fast.
Re: limiter for my china girl
finding a switch that is easilty hidden that can handle 400 volts...
I could do that, however it wouldn't be cheap :S
finding a switch that is easilty hidden that can handle 400 volts...
We know that as the RPM increases, so does the voltage from the magneto, so it is possible to design a voltage-controlled switch that could short out the gate of the SCR in order to shut down the engine if a certain RPM is exceeded.
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