Leaky CDI

Diablo007 · December 20, 2021, 03:22:42 PM

Picked up an almost all original TA125 with spares. From what I can tell the only mods were the 2T oil pump has been removed and the oil tank bottom was cut out of the seat, maybe an aftermarket kill button. With luck and a lot of searching I think I can find the original bill of sale. Still has the tech inspection sticker from the last race it was in on the upper fairing. I'm in the process of cleaning it up so I can bring it inside to put in my office. Apparently the CDI didn't like being disturbed as it leaked a bunch of the resin type substance. It had a little on it when I removed it so I'm not too surprised it leaked. My question is what do I need to do to keep it from leaking more? Do I let it drain and then fill it and seal it? If so what do I use? I did some quick searching and it seems there may be places that can take care of the issue, but didn't name any.

Any ideas or information would be appreciated.

m in sc · December 20, 2021, 04:22:47 PM

you need potting compound. fwiw, you can actually use caswell tank liner to pot electronics. ;)

teazer · December 20, 2021, 06:09:14 PM

Nice looking TA. They are cute little bikes.

The CDI on that bike should be a TIA-02 IIRC so it's basically a version of the TD/TR and TZ boxes. That black goop should be chemically and thermally stable and should not "leak" unless it has been exposed to a solvent like MEK or similar which can turn the potting compound to goop. I haven't seen one dissolve before. It should not be liquid. It's a chemical potting compound that sets hard and normally stays that way.

It doesn't much matter if it all "leaks out" unless you plan on running it. The circuits are potted to protect all the old school components from vibrating and cracking. The simple solution is to send it to Rex's Speed Shop in the UK and have them empty out the old CDI box and fit a new circuit board assembly with new wires and connectors.

They did one for me recently and it looks like new and works like a charm.

If it will just be an office/shop ornament, you can seal it up or even dissolve the rest of the resin and tip out the contents. No one else will notice that it's not wired up.

SoCal250 · December 20, 2021, 11:56:50 PM

Congrats on the TA! Looks like you found a nice one. I'm very jealous!
After a restoration in the office (assuming this is the plan), I hope you put it back on the track where it belongs and put it through its paces.

Diablo007 · December 21, 2021, 01:38:07 PM

Thanks for the input and comments!

@m: 'potting compound'...as soon as I read that it was a 'doh' moment. Haven't thought of or used the stuff in a very long time. Thanks!

@teazer: ''Rex's Speed Shop', I forgot that they can do this. Thanks for the reminder!

@SoCal250: Unfortunately we no longer have a race track, so for the time being it will just be cleaned and made as ready to race as I can get it, then displayed.

sav0r · December 21, 2021, 01:54:44 PM

Potting epoxy is easily purchased from McMaster. It's what I use with the solid state regulator that I build in house.

bitzz · December 21, 2021, 05:49:36 PM

Center stand?
Is it a "kitted" As3?

I have a factory TA125 and it never had an oil pump or center stand. Does it have this sticker on the head stay? https://imgur.com/uUEsqXl

I have a couple of those CDIs if you NEED one. ( I think I have a NOS one, a freshly rebuilt one and a used one) https://i.imgur.com/NcolSbJ.jpg
I have limited spares if you need.

still have my email?
... and because I am a nosy shit, I would like to know what you paid for it.

pidjones · December 22, 2021, 06:23:30 AM

Might have been re-potted with a non-compatible compound. We had that on a DC high voltage supply once at work - they didn't dig and clean 100% of the old compound out when the repaired it, and the new potting never set up. Was a real mess to clean out, but once thoroughly cleaned re-potted just fine. The potting on CB750 ignitirs was notorious for leaking out. Folks just wiped up the mess and kept using them.

Diablo007 · December 29, 2021, 01:19:05 AM

Sorry, for some reason I don't get email notifications, even though the box is checked.

The center stand is most likely from something else. My friend has been working on Yamaha's bikes since Yamaha began importing them and knows what parts will work with what bikes. If your TA doesn't allow for a center stand to be fitted I'll have to dig deeper to find the correct frame. There is another frame that looks the same in the shop but it's painted blue.

When I have time I'll go look for that sticker. It may or may not be there, but I'm 100% certain it's an all original TA125. If you look at the fiche it does show an oil pump as well as two different tail sections; presumably one with an oil tank and one without:
https://www.ronayers.com/oemparts/a/yam/5978d6b887a8661120f0772e/oil-pump
https://www.ronayers.com/oemparts/a/yam/5978d6b887a8661120f07739/seat

If memory serves me correct, now that I'm thinking about it, he did mention pulling the oil pump from a race bike because the nut spun off the gear under deceleration. Not sure what model as he raced the following; RD125 GYT kit (still in the shop), TA125 (pictured), TZ250 with a 350 top end (sold to Ed Erlenbach), RD350 (I now own it), RD400 (just finished the deal on it), and an RZ350 (I also own it). The RZ350 is the only one that still has an oil pump.

As for the potting compound destabilizing, this isn't the first time I've seen this, just didn't remember what it was. There are regulators, rectifiers, regulator/rectifiers, CDI's, fluorescent light ballasts, and other items I've seen leaking this stuff out of before. My theory is that being in Hawaii we are closer to the sun, have high humidity, and high salt content in the air. There are other things I've seen deteriorate like this, such as Lexus body panels, and the rubber on my guitar stands. It's common for rubberized things to do this here.

Feel free to flame, if you live here. Living in 'paradise' can be a bitch.

Diablo007 · December 29, 2021, 02:30:07 AM

Sorry, forgot to mention, there is no spring connected to the center stand. There is a bungee cord to hold it up when the mc is being moved.

pidjones · December 29, 2021, 06:47:53 AM

The rubber on your guitar stand is probably "surgical" rubber tubing made of natural rubber and it degrades with time no matter the environment. Mine all need new tubing in Tennessee.

Striker1423 · December 29, 2021, 08:40:49 AM

Yea they turn orange, hard and then fall apart. My dad's guitar stands all.dod that after so many years of use.

Diablo007 · December 29, 2021, 04:34:06 PM

@pidjones: What did you use to remove all the potting compound? Right now I just have it sitting over a container and dripping out. Eventually it will stop and the remaining compound will have to be manually cleaned out.

pidjones · December 29, 2021, 08:53:47 PM

Quote from: Diablo007 on December 29, 2021, 04:34:06 PM
@pidjones: What did you use to remove all the potting compound? Right now I just have it sitting over a container and dripping out. Eventually it will stop and the remaining compound will have to be manually cleaned out.

As I remember, they dug it out manually (took a while and they used several different tools) and were very careful to research compatibility of the compound that they re-potted it with. And they were vacuum potted (compound mixed and added, then the device placed in a vacuum to draw all air out). This was a supply that ran at 50 kV DC.

Diablo007 · January 03, 2022, 01:56:32 AM

I let the tarry substance drain for a couple of days. Pics are what it looked like after. I tried cleaning the sticky outside with acetone, didn't work well. MEK did the trick but I'm pretty sure filling the CDI with MEK to get rid of the remaining potting compound would ruin the electronics. Any ideas?

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Leaky CDI

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