Why can't a CDI from one bandit work in another?

[Kenyan01]

Hi!
I've been niggling this thought in my mind for ages but I cannot seem to get an answer that makes simple logical sense.

If two B4s from the same year have differently numbered cdi's, I presume there is nothing else in these bikes that would be different. So, why is it that the specific cdi number is the one I must replace it with?

I once bought a different cdi and it would not fire the bike. So, we replaced a few suspicious looking components on the old one with some from the new one and the bike fired immediately.

Please help me understand this cdi mystery.
Patrick.

[gsxr400 racer]

the timming  rotor behind the left engine cover must be changed ran into the same problem

[PitterB4]

So, there is a matching CDI and timing rotor for each model/year combination?

So somone buying your GSXR CDI, Jay, would need a GSXR rotor, too?

[gsxr400 racer]

there are only 2 rotors out there that i know of one that works and one that doesnt the p model cdi i have has the extra green and yellow wire this is the one that i think is limited to retard/advance the timing once it hits 12500 rpm and the others are not ! I had sent ya that cdi wich didnt work in your bike nor did any of the gsxr ones that i had worked but then i changed the rotor and now the p model doesnt work and all 7 that i have do ! So go figure!

[Kenyan01]

That's very enlightening!
What I noticed with the new CDI I bought was that it fired the spark plugs after I stopped cranking the bike, and now it all makes some sense in that the new cdi was not in timing with the piston positions of the cylinders and thus advancing or retarding the timing by rotating the rotor could have sorted out the problem! Correct me if my interpretation is all wrong, please.
Patrick.

[PitterB4]

Good question.  

I have tried two other, differently numbered CDIs (Todd -   ) in my bike and got absolutely, positively nothing.  No click.  No crank.  No juice at all.  Nuthin'!

[terrebandit]

Is this true only for B-4's?  What about B-6's and B-12's?

Dave

[gsxr400 racer]

what model is yours ROB?
Yes i think it goes for them all , if you have a known good cdi and it doesnt work in your bike then you prob. got to change the rotor or check out the pickup!
On our bikes you can not move the rotor cuase it is set in place on the crank.
If i can find them ill post a pick!

[PitterB4]

what model is yours ROB?

I've got a '93/P.

[gsxr400 racer]

so yours has a extra wire on the cdi then coming from the neutral indicator switch!

[Kenyan01]

Cars of old times, like 1996 Camry have distributors and ECU. The ECUs pretty much resemble the CDIs in bikes.

I never saw a distributor on the bikes, but my experience is pretty limited.
If there were a timing problem in these cars within certain normal limits, the distributor rotor can be adjusted back or forth to get the correct timing. What is the equivalent of a distirbutor in our bikes? If it's the CDI, then it would be acting both as the ECU and distributor?

Cheers!
Patrick.

[gsxr400 racer]

the singnal comes from a pickup wich acts as a switch , that switch picks up its signal from a fixed rotor conected to the crank wich has tabs on it that when they go past the pick up they throw off a signal that it sent to the cdi (ignitor box) from then the cdi controls the advance and the spark! hope that helped!

[Red01]

I never saw a distributor on the bikes, but my experience is pretty limited.

Some of the multi-cylinder bikes of old had distributors, but by the mid-1960's I think they were pretty much history. If you look at some old Harleys, BMW's, Triumphs, BSA's, etc. you might see one. I don't recall ever seeing a Japanese bike with one though. Even in the points & condenser days, they were distrubutorless.