Cheap CDI

skrew37 · Jun 28, 2011

UPDATE:
Bad news. While removing the plastic plug casing to expose more of the pins to solder jumpers to, I accidentally snapped off a pin. Since the whole thing is filled with epoxy, it's impossible to even dig it away to expose enough of the pin to solder to. This might be a good sign to follow more experienced people's work on these...

rustycase · Jun 29, 2011

Do you have a dremel tool so you can grind away at enough of the epoxy so you can solder a lead onto what was running to the pin?

Good luck
rc

skrew37 · Jun 29, 2011

I tried that. Then I started nipping away at the case itself and found nothing. It was a lost cause and a waste of $6 on my part. I couldn't find the wiring harness I needed as soon as I wanted it and rushed things. I hate ruining things that could have been something. Oh well, c'est la vie...

rohmell · Jun 29, 2011

Some potting compounds can be softened with MEK. If you have some lying around, you could let the CDI soak for a while in some MEK.

I would mention DMSO, but I won't, that stuff will eff you up.

skrew37 · Jun 29, 2011

I don't have any of that lying around unfortunately. Maybe I'll keep chipping and gnawing away at it until I find something recognizable. I'll definitely have to excavate the components.

skrew37 · Jul 8, 2011

Ok. Round 2. I decided to give it another try before I build my own CDI. I bought a cheap racing CDI that looks almost identical to the JN Motors unit. How do I hook this up? I'll be using a CR80 iginition coil with it as well. It has 5 wires which are all red and black...Any help?

DuctTapedGoat · Jul 8, 2011

One of those is orange, not red. That's the one that'll go to the coil Orange = fire, black = ground.

skrew37 · Jul 8, 2011

Ok thanks. So the orange and black go to the positive and negative (respectively)on the coil, the black wire on the left in the pic is ground? and the other 2 go to the black and blue wires from the engine? Obviously I'm guessing here...

rustycase · Jul 8, 2011

What a nice looking cdi, skrew!
probably better looking than most could build at home.
As DTG said, there's an orange, a red with a stripe, and one of the blacks is paired with another wire.
Seller really has a responsibility to provide you with a diagram, IMO.
Otherwise, 'Thevenin's Theorem' it is, for reverse engineering.

What was your source?

I'll look forward to seeing your running results posted!
Best
rc

DuctTapedGoat · Jul 8, 2011

Well, no.

I would do this personally.

Orange/Black - To Coil.
Black Motor - Black CDI.
Blue Motor - x1 Red CDI.
White Motor - Wire Cap.
x1 Red CDI - Wire Cap.

Please, if anyone knows why this isn't a good way to wire, speak up. Seems to me this is how I would try though.

Note though, you could prolly wire a tachometer to the other red wire no problem at all.

skrew37 · Jul 8, 2011

OK. Like this?

DuctTapedGoat · Jul 8, 2011

I would say correct, but I can't be sure I'M correct, but yes, that's what I would try.

skrew37 · Jul 8, 2011

rustycase said:
What a nice looking cdi, skrew!
probably better looking than most could build at home.
As DTG said, there's an orange, a red with a stripe, and one of the blacks is paired with another wire.
Seller really has a responsibility to provide you with a diagram, IMO.
Otherwise, 'Thevenin's Theorem' it is, for reverse engineering.

What was your source?

I'll look forward to seeing your running results posted!
Best
rc

I got it here:
2 STROKE RACE CDI IGNITION JOG Minarelli 1PE40QMB | eBay
There are 5 left.

skrew37 · Jul 8, 2011

What kind of tachometer do you think I should look for if I choose to try to run one?

DuctTapedGoat · Jul 8, 2011

Something like a Dwell Tachometer/Volt Analyzer. HF has them all day long.

skrew37 · Jul 8, 2011

Thanks. I'll look in to it.

skrew37 · Jul 11, 2011

I received an email from the merchant with the wiring diagram. I'm still a little foggy on the connections, keep in mind I'm still learning. Here's what they sent:

DuctTapedGoat · Jul 11, 2011

Blue from motor goes to EXT.
Coil goes to IGN.
Kill switch goes to SW.
Black from motor (Ground) goes to E.

It shows PC going to ground, but I would cap it and leave it alone.

skrew37 · Jul 11, 2011

Thanks! Now I just have to wait till it gets here. In the meantime, I need to check for some air leaks and build a new tank bracket which snapped from vibrations this weekend. Maybe I'll use steel instead of the aluminum strip I had laying around.

DuctTapedGoat · Jul 11, 2011

You're welcome - now of course, that's just after a 30 second glance at the attachments you posted, I could be wrong, but it seems to add up.

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