Capacitive Discharge Ignition(CDi) modification?

Question

Is there any cheap ways to modify the CDI system(lets say for a small motorbike) in order to get a desired timing curve? Currently the CDi that ive got(on a suzuki dr125) runs at 14degress at low rpm and will go up to 30degrees at high rpm.

suzuki dr125 4 stroke.The reason why i want to modify is because i wanted the engine to run on alcohol.

Answer 1

A DR125-2 Stroke,,
or a DRZ 125 -4 stroke?

No Matter,,,just curious,,it's unusual to see a 125 2 stroke with an ignition advance of any type,,,,especially not such a wide range.

No wonder You'd be interested in Mods,,,that much retard would kill a 2 stroke's power at low speeds
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You'd need a Schematic of the particular CDI box,,
a good bit of test equipment,
and the ability to work at board level

Several CDI's have been "hacked" over the years,,,especially early on when the internals were standard semiconductor components.
Most late boxes use SMT stuff.

Not necessarily a CHEAP way,,,,but typically the most Practical way to attain a different curve is to simply replace the Box.

Cross fit a CDI Box from something else

Lots of the Cheapie Chinese boxes can be made to work,most have static timing values.
Some have variable advance.
But they too are not user-adjustable/programmable to allow experimentation.

Cheap though,,,as low as $10~15USD on Ebay

btw,, Though yours doesnt have a centrifugal advance,,
lightening flyweights does NOT hasten the advance curve.
It slows the rate.

Less Centrifugal Force from Lighter weights working vs a given spring tension requires MORE Rpm to achieve more advance,,,,and abide by laws of physics

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If You are really intent on such a project,,
There's plenty of info available about constructing CDI boxes from scratch.
Not too bad a soldering project,,and few simple additions can make it adjustable,,,
or far easier to Mod/adjust/experiment than a factory box

Answer 2

For engines with the magnetic pickups (pulser coils) mounted on the conventional "breaker plate", you could elongate the holes in the plate and rotate the plate slightly. Why do you want to change the timing? Advance it too much and detonation (pinging) could be a problem and burn holes in the piston. If you want it to advance at a lower rpm and it has a centrifugal type advancer, grinding metal off the flyweights will lighten them and allow it to advance sooner. If the advance is controlled by the CDI box itself, there isn't much you can to about it.

Answer 3

Hi bikinkkawboy ! I have a GY-6 150cc "jonway" This scooter need to replace the CDI box... My surprice when look for a new one was: the box has an extra wire.... is it A Capacitive Discharge Ignition? if not ; What is it extra wire and what it function perform??? Thanks for Your colaboration!!!! Walter Prieto ( [e-mail])

Aw. Didn t see many CDI with extra wire!

Answer 4

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