I KEEP BLOWING NEW CDI's AC vs DC

[gmcjetpilot]

OK so I got educated in the AC vs DC CDI. But I keep smoking CDI's.

The first one I ordered in the blind and it was AC CDI... It fried in seconds. I determined I have a DC system. The one I bought is one of those $8 ebay orange CDI's.

I ordered a different more expensive DC CDI, CASOLI "CF250". It also fried.

What am I doing wrong. May be my scooter has different wiring. I saw one youtube video where you have to pull one wire out of the connector on the bike side?

Why change the stock one? Well the scooter runs fine but cuts out at 48 MPH like clock work, like the ignition is being turned off and then on... or like the throttle is instantly closed than opened again, IE Cutting out. I wanted to try a "racing" CDI with out a REV limiter. Not sure my stock CDI has a limiter.

[tortoise]

Originally Posted by gmcjetpilot

my scooter

For others curious . . previous post references a BMS Prestige 150 . . parts reference image shows a DC-CDI.

[gmcjetpilot]

Originally Posted by tortoise

For others curious . . previous post references a BMS Prestige 150 . . parts reference image shows a DC-CDI.

Thanks that is my thread with ZERO replies. I thought I take a different tact at it. My new question is about frying my aftermarket CDI's. Cheers

[cheesy]

Does the scoot still run on the original CDI? If yes, I'd break out my VOM and check the output at the VR to the CDI. Really shouldn't see more than 14.7 volts in a DC system.

If no, still using the VOM, I'd start checking for a dead short to ground at the CDI harness plug. If that checks out good, I suspect pin out between the CDI and the harness may be different. Had that issue with my Hi-bird many years ago.

[ben2go]

You say the original CDI breaks up at top speed. I wonder if you're maxing out the engine's rpm and hitting the rev limiter. That's what it sounds like to me. If that's the case, you can work on final drive gearing and variator/CVT tuning for more speed. I am not familar with tuning the variator/CVT.

[cheesy]

Originally Posted by ben2go

You say the original CDI breaks up at top speed. I wonder if you're maxing out the engine's rpm and hitting the rev limiter. That's what it sounds like to me. If that's the case, you can work on final drive gearing and variator/CVT tuning for more speed. I am not familar with tuning the variator/CVT.

And what he said.

[gmcjetpilot]

Originally Posted by ben2go

You say the original CDI breaks up at top speed. I wonder if you're maxing out the engine's rpm and hitting the rev limiter. That's what it sounds like to me. If that's the case, you can work on final drive gearing and variator/CVT tuning for more speed. I am not familar with tuning the variator/CVT.

I would love to swap out the CDI for one that doesn't have a rev limiter (assuming original CDI even has Rev limeter) But as I said I've tried to replace the original CDI with two aftermarket ones that just fizzle, as soon as I install them and turn the ignition on. First One was an AC (my mistake) and one was a DC CDI (which is correct but still fizzled). I'll look into changing the weights or gearing. Thanks for advice.