Replacing a "Spark Unit" / "Igniter" / CDI (OKI MPS-200) on a '80 CB650
So since I apparently need to pose this question in different forums (a Honda-specific one was no help), I thought "surely the lot at GSResources is among the capable". So, here we go:
The bike in question is a '80 Honda CB650 (i think designated CB650Z in NA market), which – from what I could gather – sports a transistorized capacitor discharge ignition. So, it doesn't have points, just an inductive pickup, two of what Honda calls a "spark unit" and ignition coils. That's it. The spark units basically contain all the circuitry, and are marked as OKI MPS-200.
The circuits of these are potted, but apparently this potty (putty?) degrades after 40years in such a way that heat will make it runny, exposing the circuity (That is apparently a known problem, since a cursory google search reveals others having the same problem). And there's enough heat to go around; not only from the engine but also the units themselves do generate enough of it, apparently.
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 of a 4 in-line, 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 how close the primary coil voltage needs to match...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.
By any chance anyone of you already did something along these lines?
Here's a schematic of the original unit (the dashed rectangle) & ignition:
So since I apparently need to pose this question in different forums (a Honda-specific one was no help), I thought "surely the lot at GSResources is among the capable". So, here we go:
The bike in question is a '80 Honda CB650 (i think designated CB650Z in NA market), which – from what I could gather – sports a transistorized capacitor discharge ignition. So, it doesn't have points, just an inductive pickup, two of what Honda calls a "spark unit" and ignition coils. That's it. The spark units basically contain all the circuitry, and are marked as OKI MPS-200.
The circuits of these are potted, but apparently this potty (putty?) degrades after 40years in such a way that heat will make it runny, exposing the circuity (That is apparently a known problem, since a cursory google search reveals others having the same problem). And there's enough heat to go around; not only from the engine but also the units themselves do generate enough of it, apparently.
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 of a 4 in-line, 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 how close the primary coil voltage needs to match...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.
By any chance anyone of you already did something along these lines?
Here's a schematic of the original unit (the dashed rectangle) & ignition:
