Spark plug boot

Discussion in 'General Questions' started by Al.Fisherman, Aug 22, 2009.

  1. Al.Fisherman

    Al.Fisherman Active Member

    I bought a kit, one much like a BGF and my Son and I put it together. Upon installing the CDI and connecting the spark plug wire to the plug, I didn't like the fit. Against my better judgment (and my Son's impatience to ride) I didn't change anything, that was until my Son gives me a call 10 miles down the road and tells me he has problems. When he mentions the word "plug" I KNOW without another word what the issue is. The boot and terminal won't stay on and make a good connection. Told him to find something like a piece of wire or aluminum foil to use as a wedge. As a last resort take a piece of cord and tie the boot securely to the plug. When he got home we pulled the boot to inspect, and cut it as close as I could to the end. My neighbor has a lawn mower that threw a rod, so I went to his mower and cut off the boot. I used both the coil and boot on the bike engine, A little WD-40 works wonders in sliding the boot onto the CDI wire

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  2. mattysids

    mattysids Member

    Are you saying that you just pulled the wire+boot from the other engine and somehow attached it to the severed one coming from the CDI?

    How do you go about doing this?
  3. Busaman

    Busaman New Member

    You may need to take the copper tip off the top of the plug. Thats how mine fitted in there.
  4. Al.Fisherman

    Al.Fisherman Active Member

    First, my spark plug is Chineese...go figure. Well when I took the plug out of the package the tip had threads and a threaded top (cap) was included in the parts. You are to use what is needed (my CDI needed the threads exposed on the plug). Upon installing the plug and installing the plug boot from the CDI, I noticed it wasn't a GOOD fit. I didn't like the fit, but I thought I'd change it later. Before I did my Son had trouble about 8 miles from the house. (He called and I told him how to jury rig it till he made it home).

    First photo is a picture of the bike CDI..I cut the boot at the point of the arrow tip. I also did the same with the lawn mower coil.

    Second photo is the spark plug that came with my kit..notice the threaded top.

    Third photo is of a replacement plug..NGK or whatever that the top can't screw off. I read on this forum that someone told that the non threaded plug had to have the top ground down...that is not the way to do it, if for NO other reason you may not be close to a grinder as on a trip.

    To replace boot and clip...after the boot from my CDI was removed (I couldn't reuse it..molded on) I slid the lawn mower boot onto the CDI wire with help of a SMALL amount of WD-40..or the like. Then I lade the coil clip beside the plug wire and found where I wanted the clip contact to insert into the wire. I then took a ice pick and pierced the plug wire insulation. I installed the clip and pulled the boot over the plug clip. This makes for the best conection.

    Attached Files:

    velzie likes this.
  5. Al.Fisherman

    Al.Fisherman Active Member

    Pictures added

    Pictures are indeed worth a 1,000 words. By the way look at the first photo (P8230144) and see how I ran the CDI leads to the mag, through the down tube.

    Attached Files:

    Last edited: Aug 23, 2009
  6. Pablo

    Pablo Motored Bikes Sponsor

    I recommend silicone grease for those connections, provides the lube (without harm), seals and does not conduct the same as WD-40.

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  7. Al.Fisherman

    Al.Fisherman Active Member


    I agree but I needed like a drop to smear on the wire so the boot would slide...that is what I had that is what I used. Wasn't needed for the conection. I could of used spit.
    Last edited: Aug 23, 2009