Installed new CDI and blew a starter fuse, why?
 

Installed a new coil and CDI, went to turn it over and it wouldn't start. Tried again and the starter fuse was blown, so I swapped the old CDI back in and replaced the fuse, all is now good, but I'm assuming I got a bad CDI, any ideas why it would have caused the fuse to blow?

it could be also that you got the wrong type of CDI. sure you got the right kind. there are ac and dc type CDI"s

Is it possible that you shorted something while doing the swap?

I'm pretty sure it's the right one - they're both the same plugs, one 4-pin and one 2-pin ... Also I disconnected the battery prior to the swaps, which were pretty straightforward. How do I ascertain for sure if I have an AC or DC CDI prior to contacting the vendor for a replacement?

what kind of buggy do you have? buggy name brand or motor name brand or some pics of it

I have 2 Tomberlin crossfire buggies with the Howhit motor and I know they are AC cdi"s the Helix I use to own from ASW was DC cdi"s

It's a ASW Helix 150cc .... Shouldn't the plugs be different from AC to DC ?!?!

no the plugs would be the same, it is the number of wires going to the plugs that make the difference. I will see if I can find something for you to tell the diff. my helix was a dc cdi. DC are not as common as ac ones.

here is a wiring diagram

DC cdi is much larger in size than ac.

From what I've read that is.

it is larger

i've got a couple that are identical in size--came with the carter talon engine.

the cdi on my Helix was larger than the one on the crossfires.

I'd contact the seller to be sure of what you got!

I keep reading about this check. I did the same and ordered a DC CDI

Turn your ignition on with engine off and turn on your headlights. If your headlights come on you probably have a DC CDI.
If you have 1 wire going to the 2 wire plug on your cdi then you probably have a dc cdi.

And if you just ordered any old cdi off the internet then you probably got an ac cdi because they are the most common.

check those and see what ya got.

outcry check the post date on this post, it was last answered by the op [original poster] back in June.

I blew the starter fuse 2 weekends ago when I put the orange cdi in our 183cc stroker motor. It didn't happen the first time but I went back to the stock cdi because the advanced cdi has no top end with the stroker motor.

I never had the problem of blowing the fuse until I installed the 11 pole stator. It always seemed to blow after winding out engine then letting off the gas. As the engine spooled down the fuse would blow. I come across a thread on one of the scooter forums which said the problem was due to the large stator causing an unstable current which will spike causing fuse to blow. At the time I just kept fuses on hand since it did not always do it. Eventually I had to rewire my buggy due to corrosion of the wires which had run through the tube frame. I had rewired using 14 ga. wire and have not had this problem since. At one time MRP sold a current stabilizer for the GY6 scooter but have never known anyone who used one.