OKI MPS-200 replacement


CB750 New member
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CH (no, not CN)
Hiya all,

first of all, sorry for asking a question related to a CB650, not 750 - but as far as I understand, it's the same ignition, so I hope it's okay for this one.

So, I'm currently restoring that bike, and I've encountered the "runny potty" problem of the igniters. While there are replacements available, either they're priced completely bonkers, or it's used ones where there's no guarantee for them not having the same problem.

So I thought, "eh, CDI / transistorized ignitions must be a bog-standard thing by now", and sure enough, by searching for "6 pin DC CDI" you'll find dozens. They all seem if not the same, then just slight variations of a standard one. And judging by how they should be connected to the engine & rest of the ignition, and the MPS-200's schematic, those run-of-the-mill CDI's should be a drop-in replacement (well, needs some connector crimping) for the OKI one.

The only things I'm wondering at this point is firstly wether these units can handle the rpm's, since most of them are marketed towards the ATV/scooter crowd and often have something along the lines of "150-250 cc" in their title (It's my understanding however that an ignition doesn't care too much about your CC's). Secondly, I'm not sure what the stock primary voltage is...I suppose there's a bit of leeway, but I reckon if voltage of the new CDI is too low, I'll get a weak spark, too high, I might run the risk of frying the coils.

Anyway, by any chance anyone of you already did something along these lines?
So, as in update here; I've decided to simply re-seal the igniters with a modern epoxy. Cleaned them up slightly beforehand, but not touching the circuits (can't really work in there without damaging stuff).

Worked well so far, bike is happy back on the street.
What did you use to clean out the old tar like goo that was dripping out before sealing with epoxy?
Just an old screwdriver, a carpet knife, lots of paper towels. As I wrote, I did not clean the goo out of the circuit, instead I made sure that the new epoxy has enough clean metal available to make a bond, sealing in the remaining crappy goo.