Roll Your Own CDI
- Thread starter rohmell
- Start date
Hi rohmell!
Great thread, thanks for the schematic. I have all but 3 parts to breadboard my CDI. I'll post an update after I get it working with pictures.
Dave
AssembleThis
Great thread, thanks for the schematic. I have all but 3 parts to breadboard my CDI. I'll post an update after I get it working with pictures.
Dave
AssembleThis
See CDI circuits in my photo album. Can the factory kill-sw be used as in the Honda circuit? Is this safer than the normal (short out the magneto) method, which I read could damage something.
Have ordered SCR to build the fully adjustable circuit (JAG and other) and want to 1 to 1.5uF for main cap (maybe 3 caps; 1uF and two 0u22F, with jumpers giving: 1, 1.22 & 1.44uF, see what works better and if I need more/ less).
As for the rpm sensitive advancement (parallel capacitors to the right of the circuits):
With 2 jumpers/switches, 3.3uF, 1 and 2u2F (2.2uF) to give me 3.3, 4.3, 5.5 and 6.5.
Or with 3 switches/ jumpers, 3.3uF, 0.47, 1 and 2u2F will result in 3.3, 3.8, 4.3, 4.8, 5.5, 6, 6.5 & 7uF. Just depends how much adjustment u want.
Not sure about the low input resistance of the Honda cct (circuit), but I would like to use the original kill-sw.
I think the "full" cct can do all and more than the simpler ccts.
I talked to a mate of mine about it and he gave me a quad coil for free, awesome start.
PS: I am interested in the temperature compensation of the thermistor. How effective would it be? It only senses ambient temp. not engine temp (unless fixed to the engine, I suppose).
PPS: Thanks to all the people that made these awesome circuits available to us!
Have ordered SCR to build the fully adjustable circuit (JAG and other) and want to 1 to 1.5uF for main cap (maybe 3 caps; 1uF and two 0u22F, with jumpers giving: 1, 1.22 & 1.44uF, see what works better and if I need more/ less).
As for the rpm sensitive advancement (parallel capacitors to the right of the circuits):
With 2 jumpers/switches, 3.3uF, 1 and 2u2F (2.2uF) to give me 3.3, 4.3, 5.5 and 6.5.
Or with 3 switches/ jumpers, 3.3uF, 0.47, 1 and 2u2F will result in 3.3, 3.8, 4.3, 4.8, 5.5, 6, 6.5 & 7uF. Just depends how much adjustment u want.
Not sure about the low input resistance of the Honda cct (circuit), but I would like to use the original kill-sw.
I think the "full" cct can do all and more than the simpler ccts.
I talked to a mate of mine about it and he gave me a quad coil for free, awesome start.
PS: I am interested in the temperature compensation of the thermistor. How effective would it be? It only senses ambient temp. not engine temp (unless fixed to the engine, I suppose).
PPS: Thanks to all the people that made these awesome circuits available to us!
Last edited:
Don't forget what a circuit pattern really is at the end of the day guys!
Any circuit should support being connected as a passive continuous loop, and put your bike in that circuit.
Any circuit should support being connected as a passive continuous loop, and put your bike in that circuit.
Sorry rohmell, the gate section is slighly different (simpler), but i don't beleive that gate and cathode and reversed. Simply, that wouldn't work, as a scr has only 1 configuration, as opposed to a transistor.The scr has the same means and function in all of the circuits in my photo album.
I have many years of electronics experience , advanced diploma in electronics and communications and have completed most of my electrical and electronics degree.
Ducttapedgoat, not sure what yr trying to say.
I have many years of electronics experience , advanced diploma in electronics and communications and have completed most of my electrical and electronics degree.
Ducttapedgoat, not sure what yr trying to say.
Last edited:
@Electron :
If I have a 5 point circuit composed of say,
1 MOSFET Transistor
1 Capacitor
1 Fuse
1 Diode
1 Bicycle Engine
If the circuit is done properly and the right parts are used, the 1 Bicycle Engine should be able to be inserted at any point throughout the circuit.
Example, the 1 Bicycle Engine could be;
Between the FUSE and DIODE
Between the MOSFET and DIODE
Between the CAPACITOR and FUSE
In theory, so long as the circuit is done properly, the bicycle engine will work with the same results no matter where in-line it is placed within the circuit, so long as the circuit maintains a continuous loop.
If I have a 5 point circuit composed of say,
1 MOSFET Transistor
1 Capacitor
1 Fuse
1 Diode
1 Bicycle Engine
If the circuit is done properly and the right parts are used, the 1 Bicycle Engine should be able to be inserted at any point throughout the circuit.
Example, the 1 Bicycle Engine could be;
Between the FUSE and DIODE
Between the MOSFET and DIODE
Between the CAPACITOR and FUSE
In theory, so long as the circuit is done properly, the bicycle engine will work with the same results no matter where in-line it is placed within the circuit, so long as the circuit maintains a continuous loop.
I would agree with dtgoat if it was 1 single current loop, but The cdi circuits are make up of many current loops. It is important to wire it exactly as the cicuit describes. Also you connect a magneto and coil, u cannot connect an "engine" to an electrical circuit. There is NO fuse in the circuits described.
is there anyway to incorporate a pick up coil input into this circuit so it would have ac strator in, ground , trigger, then output to coil?
hey all,
just made my profile because of this thread and wanted to ask a few questions.
how would i use a flyback coil this is a link to the one i pulled.
http://www.shopjimmy.com/asti-3739-fbt-l40b17300.htm
and i would like to build a cdi that will give me the most top end performance out of my bike.
do the resistors need to have a certain rating
how do i tell what diodes i have
also what is the best src
sorry i have alot of questions it has been awhile since i messed around with circuits
thank you everyone for all the information in this thread it is awesome and inspired me to tryout my own and ask questions
just made my profile because of this thread and wanted to ask a few questions.
how would i use a flyback coil this is a link to the one i pulled.
http://www.shopjimmy.com/asti-3739-fbt-l40b17300.htm
and i would like to build a cdi that will give me the most top end performance out of my bike.
do the resistors need to have a certain rating
how do i tell what diodes i have
also what is the best src
sorry i have alot of questions it has been awhile since i messed around with circuits
thank you everyone for all the information in this thread it is awesome and inspired me to tryout my own and ask questions
Hi guys. As yawl can see I'm a noob on this forum. I'd just like to know one thing. Would the ordinary CDi ,that rohmell made , work if my stator (black wire) only produces about +-15 volts .
Thanks in advance
Thanks in advance
it should if that's what the rest produce. I had one of the first Jag units made and it worked great. The fault in the system is in the stock magneto, it's junk. Get the replacement magneto off eBay and replace the stock unit. Keep it as a spare. The ones made for the aftermarket are of a much higher quality.
Hey guys, I see that the thread is pretty dead and the info are quite outdated. But I just wanted to confirm that the schematics dracothered drew is a well working / proven circuit before I go all out and make one myself.
Also is the HD lightning (huffydavidson) using the same schematics? few mentions at around 50 pages in but it was quite vague. Thanks in advance.
Also is the HD lightning (huffydavidson) using the same schematics? few mentions at around 50 pages in but it was quite vague. Thanks in advance.
Didn't mean to come out sounding rude, but just want to make sure it's up to date. Figured since it's been a good few years since the schematics were drawn, there would have been small changes, new ideas, improvements etc.
Welcome to the forum. I see Rohmell is still active in this thread, and he is the resident CDI wizard.
Ah, okay. Thanks. But did you make one? Coulda sworn you said something along the lines of "my buddy likes it".No it's not even close sorry