bicycle motor spark plug wire replacement


Well-Known Member
Dec 23, 2007
Kalamazoo, MI
i thought we had this somewhere and couldn't find it. the cdi which your plug wire goes to has a screw in it that you basically screw the wire onto. a picture of the inside of the original cap is below and the cd has the same screw in it for conductivity. if you replace the wire you need 7mm good quality plug wire. to make it easier to screw into the cdi pre screw the end of the wire with a small screw like you would do with a piece of wood or metal making a pilot hole. also if you replace the boot with a good one you need to put the little screw cap on the end of the plug. you will notice a big performance change with a good wire in most cases. for me it made the biggest improvement to date on my motorized bicycle

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
up north now
Also, if you spray a little silicone on the outside, it will help it go in better and give it slightly better protection against moisture.