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View Full Version : CDI to IDI



McDerry
08-01-2006, 07:48 PM
Anyone converted a Capacitor Discharge Ignition on a three wheeler to an Inductive Discharge Ignition System?

Reason being, i got myself a 250es for free, but its misssing its CDI, coil, carburator, and quite possibly its voltage regulator and rectifier(didn't look close enough)... In addition to no rear tires or rims, no brake elvers, throttle lever, handgrips, etc. Basicly frame front tire, swinger, engine rear axle, and the racks.

Now I maybe mistaken but the pickup on the motor is a hall effect, so in theory i could run those into a ford duraspark module ($12) and have that trip the power going to the coil to fire the system. With the 200w alternator id have around 15 amps going to the stytem and charging the battery at peak. The duraspark module draws 9 amps on startup and procededs to run at 4-5 amps while the engine is running. So I think i will have enough power capacity to maintain battery charge. If all else fails ill have to slap a float charger on for at night.

Now most IDI systems wont keep up after 5,000rpm. But then again thats in automobiles, where 5,000rpm is actual 20,000 to 80,000 cycles per minute before it starts to taper off. So in theory this should eb completely capable on the one lung bike up to 5,000rpm.

hrc85250r
08-01-2006, 07:52 PM
dude, there is no spark advance like a cdi, and thats basically cobbing it up. you can get all of the parts you need either from a local scrapyard or ebay for 12$. you can try it, but i dont think its worth the effort.

Unclediezel
08-01-2006, 07:59 PM
http://webpages.marshall.edu/~baksh2/convert.html

its been done before--but like HRC85250r Mentioned , No where does it say where spark advance comes from.

McDerry
08-01-2006, 09:38 PM
Spark advance comes from the same place, cars, trucks, snowmobiles, airplanes, atv's. If there a non distributor less ignition there achieving there timing from the breaker point. The breaker point on the ATC is on the camshaft, its spring loaded with weights, as the rpm goes up the engine is advanced, your basic mechanical advance(centrifugal advance). Your not running a vacuum advance so the mechanical advance is moving in a 30 so degree arc between idle and say 5,000rpm. electric ignition modules tend to ahve a small amount of advance that there capable of and there just mimicking dwell versus actual truely advancing timing.

The resistor stuff that guy mentions is well, a waste of time and energy. Theres a start wire, he could have sent current to that and the module disables the electronic advance feature. Better yet, you just retard the timing on the pickup some more...




After parusing the PDF service manual copy I found that the timing should be at 13 degrees at 1400 rpm, and 31 degrees at 3500rpm (full advance). Use of a tachometer and a timing light can remedy that issue.

Also the duraspark gear has a price tag of $0.00

My thoughts are whats teh exciter coils output volts/watts, and I wonder if if the inductive ingnition would run with an ac charge going to it?

Unclediezel
08-01-2006, 09:47 PM
You've obviously been doing your homework!!!!! Well Done!!!!!

I'm a Yammy guy---And all we have is a spinning rotor and 4 magnets.....
I started My trizinger Basket Case with a Chrysler orange box , A pair of jumper cables and a Ford TFI coil. It ran horrible...

If you can get spark advance...GO FOR IT> If your good with electronics---pop open a junk GM alternator and Snatch the bridge rectifier. ( The internal wiring diagrams HAVE TO be somewhere on the web) And Correct AC/DC with that. NO......The Ford box will spit AC current out and wont try it a second time.

McDerry
08-01-2006, 10:00 PM
Good thinking on the rectifier.

Unclediezel
08-01-2006, 10:02 PM
This is of course , assuming your OEM rectifier is NOT present! If it is --your good to go.

trikes4life
08-02-2006, 12:16 AM
sounds easier to buy the right stuff. Thats just me though.

NewOldSchool
08-03-2006, 09:40 PM
always thinkin about the$$$$$thats good