modified cdi and cr 80 coil

Very intersting thread. I've read it completly from the first beginning. Well, after one year of hard work the J-CDI seems to be decoded sucessfully. In my opinion this is a great sucess of the members of this forum.

The only missing things are a timing light, perhaps a rpm counter and a truly fitting degree wheel. With the last position I could probably help you out.

Multipaul
 
From the schematic, I can not properly detect which signal arrives at the gate. Could someone with an oscilloscope tell me the voltage and polarity?

Multipaul
 
​
Hi, the negative voltage comes from the negative half of the same AC voltage, that the positive half of charges the charge caps. They r rectified to do this. The negative half develops over the 620 ohm resistor in the R/C timing network. The scr condust when gate is a couple or few volts negative in respect to the kathode. Cheers
 
Last edited:
ivan H said:
​
Hi, the negative voltage comes from the negative half of the same AC voltage, that the positive half of charges the charge caps. They r rectified to do this. The negative half develops over the 620 ohm resistor in the R/C timing network. The scr condust when gate is a couple or few volts negative Cheers
Click to expand...

Thank you, Ivan. I can see clearly now.

Multipaul
 
​
no problem, glad 2 help. If a few people start building them & experimenting then posting results we should be able to figure out a really well performing reliable cdi with enought options available to cover all motors, from stock to wild.. Just a note, be sure to use the 250vac X2 type polypropylene charge caps, not the speaker crossover types. Cheers punters, enjoy
 
also, I still havent learned to post photo,s off my phone, but I can email someone photo's of both sides of my cdi so they could post for everyone to see how I have laid components out & the tracks on the back of the board. Cheers
 
​
Hi, the Rohmell redrawn schematic is on page 42 of the "Roll Your Own CDI" thread. Maybe someone that is computer able could lift it over here, as its much more legible, thankyou Rohmell. The 1 posted here I drew on paper & mailed 2 Headtrauma & asked him 2 post here,,, & I was "crissed as a picket" when I drew it, as u can c. Cheers
 
I've read this thread and its hard to follow; a lot of postings don't reference what is being built. Can someone pinpoint me to a schematic for Jaguar's CDI box so I can make one myself? With the prices he and JNM are charging, they should have enough money in the bank to patent protect it. thanks!
 
​
Hi Drewd, go 2 page 17 of this thread. The 6th posting on that page is by Headtrauma. Its the schematic I snail mailled him & ask 2 post. 4 a better drawn 1 go 2 page 42 of roll ur own cdi, I asked Rohmell 2 redraw it. Its close enough 2 use & u can customize it further 2 ur liking. I've been running it 4,,, I'nt know, a long while now, maybe close 2 a year no problems. Also, someone recently emailed me thru this forum, needing 2 cure detonation occuring from using a very high comp head. I advised him the same as I've posted regarding changing resistance values to alter the timing in various ways. He emailed the other day & gave positive feedback, so if u do build & need advice just post or contact me thru the forum. Cheers
 
​
Also, I aint so sure Jaguar could patent protect, seeing as its already a knock off he might just run into a few,,, how would u say,,, obstacles. Cheers
 
Drewd said:
I've read this thread and its hard to follow; a lot of postings don't reference what is being built. Can someone pinpoint me to a schematic for Jaguar's CDI box so I can make one myself? With the prices he and JNM are charging, they should have enough money in the bank to patent protect it. thanks!
Click to expand...

I think it's a Kawasaki box if I remember right with mods.
 
Thanks everyone. I did buy a Jaguar CDI out of guilt and will use this info and wiring from the JAG CDI possess to build future ones for myself and not spend almost 90 dollars with shipping for another one.
 
​
Thats the 1 Dave C. Really, u could add as many jumpers as u like, or advance the timing, retard it, bring the point where it starts to retard forward or back, steepen or lessen the retard, change the kathode/gate relaationship. If u went to far, well I've already told how to tell if ur too advanced off ur plug, thats probly the only way u'd do harm, unless u retarded it so far u got it to run backwards, & even then it'd be a retarded fireing, so u could still change it back to where it was ok. Cheers
 
Last edited:
​
Ok, people seem 2 want more jumpers so I'm putting together another variation on this CDI with either 2 or 3 A jumpers on the initial firing point, 1 jumper between kathode & gate & 3 B jumpers on the timing retard. I'll test for a couple of weeks & if all good I'll post schematic & results. Cheers
 
​
Hi, 4 those trying 2 get the exact Jaguar circuitry, try replacing 27 ohm pulldown resistor with an 15 & 1 ohm in series, the 390 ohm between kathode & gate with 470 ohm & the 620 ohm in the timing R/C network with a 760 ohm. If someone could put a timing light on & check the timing curve against his I think it'd b pretty much in the ballpark. Cheers
 
Last edited:
​
I just checked the pic Drewd posted (thanx) in roll ur own cdi. It shows 390 ohm in series with 1K between kathode & gate. Both add on 0.47uf have jumpers 2 earth for 2 retard curves. I cant make out (on phone) the value of the resistor in top left corner above the 120 ohm add on that gives the 3rd initial firing point, maybe Drewd will identify but there u have it. This circuit is pretty forgiving of changes so dont hesitate 2 tailor 2 ur liking. Cheers
 
You're talking about this post and this image?
http://motorbicycling.com/showpost.php?p=298658&postcount=32
cdiparted.jpg
 
​
No, the image posted by Drewd on page 43 of roll ur own cdi. BTW, the resistor in upper left corner appears to be 220 ohm guys, so thats the complete circuit. I had run 1 with an 18 ohm pulldown resistor but prefered the more advanced firing of 27 ohm & have run like it 4 quite some time. I have recently added an RSE head which is pretty hi comp & havent had detonation but will try a cdi built to this spec & see which I prefer. Cheers
 
Just post the link of the actual post, it's not that difficult. I only see 11 pages because I have this set up to see 40 or 50 posts per page.
 
You must log in or register to reply here.
Back
Top