squab50
Scoot Member
Posts: 21
Location: lower saxony, germany
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Post by squab50 on Feb 24, 2022 0:55:51 GMT -5
squab50 Wow, great info here, I'm still learning how these work. I'm trying to build an AC CDI at the moment and am trying a few things you posted like dual output capacitors as well as other recommendations I have found regarding changing the curve. This is the circuit, it's not triggered by an external pick up but by the charge coil itself, would the thyristor crowbar be of use here or do you see any other modifications that would be useful? I have read that by changing the RC time constant (of the 4.7uf and 620ohm combination) that I can change the retard curve (2 stroke engine) and if I change the 16ohm resistor to say 17ohm that it will increase the initial advance amount, is this correct? Good morning, i will take a look at it tomorrow. You draw a good schematic. Very clean ;-)
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Post by Lucass2T on Feb 25, 2022 17:23:16 GMT -5
I just bought a module for the OEM ignition for my suzuki TS50's ignition. It aparently does the following:
Now I have manufactured the deceleration circuits again for the suzuki ts50x original ignition system. This circuit allows you to change from a fixed ignition point, the OEM timing is 1.3 mm (18 degrees) and favors top rpm but at the expense of the midrange, which is weak.
With the circuit mounted, the physical ignition point is set at 2.8 millimeters (27 degrees) and then it changes electronically linearly to 1 millimeter (15 degrees) at 12000 rpm this means that you have about 1.9 millimeters (22 degrees) at 6000 rpm and this does a lot for the energy in the middle register. These have been manufactured by me since 2018 and give the same results as significantly more expensive ignition systems
€30 + €7,50 (40 bucks or so) incl shipping from Sweden (I am in Holland).
I know with these non variated 2t's (with fixed ign timing) low end can really profit from advanced timing in the lower regions. I've had this Puch Maxi 1speed E50 once. It was kitted with a polini 65cc cylinder, 4 petal Polini reed kit, 19mm Dellorto PHBG and a Homoet 6P Kreidler pipe. It ran the stock points ignition first, then the electronic HPI inner rotor one. MAN, the middle area torque increased a ton!
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squab50
Scoot Member
Posts: 21
Location: lower saxony, germany
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Post by squab50 on Feb 27, 2022 14:26:47 GMT -5
today i got some time to look at your schematic. I think that diode D2 will short out the negative halfwaves from the charging coil completely! But you need them to trigger the thyristor. If D2 is removed the thyristor can be triggered because the 16ohm resistor allows ground potential to rise. D1 will act as a protection diode as D2 did before. A thyristor crowbar is not necessary because negative charge energy will be partly shorted by D1 and will not reach high enough voltages to damage the thyristor and/or capacitor. Also this CDI will fire twice on each revolution an wastes charge and spark energy. Therefore the capacitor is way too big. Try 1uF. Best solution will be an external pickup which only fires once per revolution. If your rotor has 4 poles. N/S/N/S, then your CDI will do this per revolution: charge,fire,charge,fire With external Pickup it will does this: charge,do nothing,charge,fire
So it will have more time to charge the capacitor and will only fire once. win win situation =)
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Post by atys77 on Jan 11, 2023 8:37:54 GMT -5
Hello everyone
this post was interesting. is there a sequel? experience with DIY CDI? I'm thinking about building it..
Greetings from hungary Attila
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Post by jco3 on Jan 19, 2023 10:52:59 GMT -5
I get a lot of the parameters, not everything but ideas pop up and then you read forum leaders have better ones also tested saving plenty of push home episodes. I found this topic absent so here it goes , so much informative CDI news but l remember a new CDI or three decorating the parts box that refuse to work and finding little help , l mean the sellers got no idea and purposely have nor give any reason and still now pretend 2t and 4t mean nothing . Its not just AC or DC that could stump people , a 4t AC or DC CDI won't run a 2t . So how to recognize 2t or 4t units is just as painful , multimeter? Goodluck. Cause is half the sparks maybe .
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