Does not come with a fortune cookie.
wouldn't it be cool if it did at lest chop sticks or a spork
wouldn't it be cool if it did at lest chop sticks or a spork
Last edited:
Roll Your Own CDI
- Thread starter rohmell
- Start date
Re: This Circuit is Retarded!
this cdi is retarded to start with as the bigger caps have a longer charge time so file the magnet's key way slot with the slot up file the right side so the magnet can be rotated counter clock wise that is advance so as when the motor revs up the magneto charge build higher the 10uF. cap charges sooner and triggers the gate sooner is further ahead of top dead center that is advance now as the rpm-s rise the time the higher charge has to charge the 10uF. cap is less,the charge to the cap curves to need a larger % of the degree to charge the cap and trips the gate later closer to tdc that's retard still ahead or tdc but retarded from the start point WELL THAT'S THE PLAN
the retard can't kick in as the 82ohm.hits before the retard-for me it just stayed stagnate so off with the retard on gos a10uF cap between the 82ohm.+and -toward the 18ohm then out with the 82ohm. replaced with a 210ohm.
this cdi is retarded to start with as the bigger caps have a longer charge time so file the magnet's key way slot with the slot up file the right side so the magnet can be rotated counter clock wise that is advance so as when the motor revs up the magneto charge build higher the 10uF. cap charges sooner and triggers the gate sooner is further ahead of top dead center that is advance now as the rpm-s rise the time the higher charge has to charge the 10uF. cap is less,the charge to the cap curves to need a larger % of the degree to charge the cap and trips the gate later closer to tdc that's retard still ahead or tdc but retarded from the start point WELL THAT'S THE PLAN
Re: This Circuit is Retarded!
[/QUOTE]
[/QUOTE]This circuit is retarded, but you may have to experiment with the 560 ohm resistor and capacitor value:
Finally finished my simple CDI and put up these pics as requested. Thank you Rohmell for all your help as well as everyone elses contributions. I have a thing for heat sinks on SCR's so I used some 1/4" copper I had laying around. I designed my board to fit in the RS project box with the heat sink sticking out the one side. The cable armor is some other junk I had lying around. Thinking of installing it on my upper cross tube just in front of my seat tube.
Attachments
Okay, lesson learned here. Don't mount any of your ignition under your seat...where your legs can touch the coil. Zap, Zap, Zap...near the family set. Bout fell off my bike while test riding it. Rode back home with my right leg sticking way out like it was broken or sumptin. Couldn't get the wife to stop laughing at me. Of course she had to tell some of my online friends. Just DON'T do it. Take my word for it.
So how's the CDI's coming guys ???
I think i'm g oing to make one without a retard and attach an ignition coil to it just to see how it all goes
I think i'm g oing to make one without a retard and attach an ignition coil to it just to see how it all goes
Hi,
Rohmell:
Im thinking about buying a performance CDI.
Are you going to sell your CDI for $50?
Will it be better than the Jaguar CDI?
What about Wolf Racing CDI or Puch CDI? How much and where?
Rohmell:
Im thinking about buying a performance CDI.
Are you going to sell your CDI for $50?
Will it be better than the Jaguar CDI?
What about Wolf Racing CDI or Puch CDI? How much and where?
Hay impression an up date I got 27* of retard -think I'm on to something aiming for a start 30* advancing to 45* or so dropping off to 25* or so?So how's the CDI's coming guys ???
I think i'm g oing to make one without a retard and attach an ignition coil to it just to see how it all goes
THE TRICK IS THE RETARD CAP HAS TO BE A HIGHER VOLT I'M USING A160V. 2.2UF.
the higher V. cap has a different charge time at lower V. then it has at the higher revs with the increased V. this seems counter intuitive I was expecting it to advance but it went in to retard creeping back toward tdc not away from it TRIPPED ME OUT THIS IS STRAIGHT VOODOO!!! 54*back to 27*
thanks again rohmell
Gonna say it one more time, Thank you Rohmell. That simple CDI is easy and fast to make, and it performs flawlessly. I can verify it produces a very nice spark....I felt it. I substituted on the diodes with 3Amp 1N5408's instead and it still works awesome. I have been gun-shy from using the chinese unit and I am going to build a back-up, for just in case. Now that I know it works, I am going to start adjusting my magneto timing. Running a new gen II Manic head and shaved the cylinder .0625" has increased my compression quite a bit and with the iridium spark plug it fires very well. Being able to trust my ignition to not puke right away has made my riding that much more fun.
I'm very happy to hear that the CDI is working well for you.
Yes, it is easy and fast to make, I hope that everyone that reads this thread makes their own CDI and enjoys the simplicity and ease of customization that it provides.
Hi
Love the idea of variable ignition timing and was wondering about the function of the 33 ohm resistor wired across the 100 ohm pot.
Would this resistor prevent a short circuit when the pot was adjusted to either extreme? Seems it would upset the 80/20 ratio mentioned elsewhere?
Is it totally necessary?
Cheers
The 100 ohm pot in parallel with the 33 ohm resistor results in a resistance of 24.8 ohms, so probably the original design called for a 25 ohm pot.
The wiper of the pot is connected to the gate of the SCR, so at one extreme ithe gate t is at the same potential as the SCR cathode, and at the other extreme, the gate is grounded.
The wiper of the pot is connected to the gate of the SCR, so at one extreme ithe gate t is at the same potential as the SCR cathode, and at the other extreme, the gate is grounded.