modified cdi and cr 80 coil

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
 
rohmell said:
Find a pic of the bottom side and then we can figure out the schematic.
Click to expand...

The Jag CDI is epoxied in the project box. I've been using one for since last summer with zero issues. It works great. (did expect the price to lower by now)

I would think a Potentiometer would actually be kinda useless, I'd be a little worried of it getting readjusted, and with jumpers or dip switches at least you know what timing your running, any kind of dial would still leave you guessing. Since the CDI is pretty much a set/tune and forget kinda thing, seems piontless.

The Jag unit I have came with 3 jumpers, the new one is A2 just above the A jumper. It cuts the the over all timing in half, So really there are 8 timing options.

Crap all I was trying to say is that I'm centralizing all the electronics into a new housing. I will be ripping my jag box open sat evening after a ride. I can identify everything on there then if you still need and maybe even get a pic of the back for you guys if you still need it.
 
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hi Lazydog, the schematic you posted is what I used as a starting point. Notice that the international model uses a 27 ohm pulldown resistor, not a 16 ohm. Charge cap is changed to 1uf to accomodate the china girls weaker stator. Cheers
 
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Hi guys. Ok, note the 27 ohm pulldown resistor. Jumper A put 120 ohm resistor in paralell with, bringing resistance down to approx 22 ohms, retarding timing by a few degrees. Feel free to experiment with 27 ohm, within reason. Increasing value advances timing & vice versa. To tell if its too advanced check plug. The sides of the center electrode should be entirely covered in oxides. If the very end 1/2mm or so shows bare metal its too advanced & the heat has burn the oxide off. Cheers
 
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Hi, I shoulda posted this ages ago ok. The unit I first built that I said was fireing way retarded I have found actually had a faulty SCR so,,,. To make a unit like Lazy Dog says with 2 A jumpers, u could just add another 120 ohm resistor & jumper to be used in conjunction with the first A jumper, or add a 240 ohm & jumper & use either or both to give extra settings. Also, the 620 ohm resistor in the timing circuit can be changed to alter when the retard kicks in. Increasing its value will make it kick in earlier in the rpm range, so maybe a 760 ohm would be better for a chinagirl. I'll try it out and post results. Too c a better copy of the schematic, Rohmell posted a much more legible copy in his thread entitled "roll your own cdi", thank you Rohmell. Cheers
 
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