modified cdi and cr 80 coil

impression said:
I was thinking that.

i went and bought a 1uF 450v capacitor :)

but it's polarized :S
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If it is an electrolytic capacitor, it won't last long due to the high-current pulses. The thin oxide layer that acts as an insulator inside the capacitor will likely be punctured by the pulse current.
Polyethylene or polypropylene capacitors are best for this type of application.
 
well no luck anyways the damn CDI box is filled solid.

just want a simple diagram where i can get a nice CDI going after i go to the electronic store to get the parts
 
Yes, the unlabeled component is the SCR.
I don't understand what you mean when you write which way to connect, the schematic shows how to connect all the components.
If you mean how to connect to the engine, schematic's blue goes to engine's blue, schematic's black goes to engine's black, and schematic's green goes to your ignition coil.
 
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rohmell said:
Yes, the unlabeled component is the SCR.
I don't understand what you mean when you write which way to connect, the schematic shows how to connect all the components.
If you mean how to connect to the engine, schematic's blue goes to engine's blue, schematic's black goes to engine's black, and schematic's green goes to your ignition coil.
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with the SCR it has 3 legs, the SCR's i have aren't easily identified.

not sure which leg connects where and what leg is which

the annode, kathode and gateway

we haven't covered SCR's yet in class :(

only resisters, capacitors and with a light touch upon diodes.
 
got one and love it , i have heard they are not strong but work well , i am running a walbro wb3a the carb off the kt100cc gokart with a ceramic coated piston , wolf racing cdi , with 4 settings to play with.
 
rockymountain said:
got one and love it , i have heard they are not strong but work well , i am running a walbro wb3a the carb off the kt100cc gokart with a ceramic coated piston , wolf racing cdi , with 4 settings to play with.
Click to expand...

How much and where can you get the Wolf Racing CDI?

Is it better than the Jaguar CDI?
 
hi , y find this new picture of the jags cdi qnd has a third jumper,
loock the size of the capacitors ¿?
attachment.php
 
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Hi guys,, I made a cdi using kdx schematic & resistor values given in this thread, 1uf polypropylene cap & timing caps in parralell to give 5.7uf. Didnt run,, far to retarded. After pedaling down the street it fired once thru exhaust. Tried again using normal kdx resistance values except used 28 ohm pull down resistor & 1.1k '& 470 ohm instead of thermistor. Timing caps are tantalum. Sucsess. I will experiment further once I have a timing light
 
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sorry guys, this should have been included in last post. 1.1k & 470 ohm resistors are in series, then wired in parralell with 1.8 k. The 22k resistor between the kathode & gate was omitted. The 28ohm pulldown resistor used instead of 16ohm used in the normal kdx schematic was made up using 2 resistors in series, 11ohm & 17ohm. All resistors 1/2 watt metal film, 1 percent.. I am computer illiterate & posting this of a phone but will try to get a photo of the unit & the schematic posted. It definitely runs smoother & lets the motor rev out much better
 
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Ok, can anyone identify the resistors from this photo as its hard to see on phone & my eyesight is poor. I can see that resistor labeled 470 ohm previously in this thread is 390 as in kdx schematic, i believe resistors in top left at jumper A are variations on the pull down resistor, affecting initial timing, the jumper connects them to earth. Timing network consists of620 ohm & 4.7uf tantalum in parralell with .47uf, the jumperB adds a .47uf in parralell, ' from this photo I think another resistor in parralell. . If anyone else has any ideas??? I'll post results of experimentation when I get timing light onto it. Cheers
 
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ok guys, I've been running this cdi for almost a month, almost daily & no problems. I still havent learned 2 post a photo & still posting from phone but I'll describe & maybe someone can post schematic. On page 8 this thread is link 2 kdx schematic. I used international model. 27ohm resisor from kathode 2 earth. Jumper A switches 120ohm in paralell with this 2 earth. 1.4k thermistor in paralell with 1.8k is about 786ohm, in series with 390ohm is about 1.180k. I used 1k in series with180ohm between gate & kathode. Timing circiut is as in schematic with 0.47uf tantalum cap added in paralell with 4.7uf tantalum & 620ohm resistor. Jumper B switches another 0.47uf tantalum in pralell to earth. Charge caps are 2 0.47uf 280volt polypropylene in paralell. Resistors are 1/2 watt metal film. SCR is C106D. All diodes IN4007
 
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