Spark Plug Boot Removal Issue

2007 ST1300A 99,600 miles

Ok, my first time changing the plugs (I did have it done by local Honda dealer in the past), removing one of the boots is a real pain. When I pulled the one boot/wire from the right side, front plug (its a real tight fit), the wire came out of the boot/connector.

Examined the boot/connector and the wire and it appears that the connection is a "friction" fit (wire to an internal terminal in the boot).

Replaced the boot, reinstated the wire, started the bike and all cylinders seem to be firing.

Should I do something else?

jfheilman said:

Should I do something else?

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I'd just do what you did. If you look into the plug caps you should see a little spike with threads. It's meant to screw into the high-tension/spark plug lead. It's been like this on every Honda I've ever owned.

While the leads can be tough to remove I'd be very careful how you grab the boot the next time. But you probably already know that now.

Thanks for the response ST Gul.

Yes I saw the spike thingy it was nice and shiny and had some little protrusions. I sort of thought thats the way it worked (as you stated). So, I will put the covers back on, after I change the oil and go on my way.

Again, thanks for the speedy reply.

Jim

There was a special tool for this application. Not sure if it is still available. Maybe some WD40 down the cap and allow to soak, then wash it off before starting.

You need to "screw" it back on, just not "push" it on. It's not a friction fit.

I would remove it again, cut about 1/4 inch off the end of the wire and then screw it back onto the spark plug boot to make certain it is secured properly.

It's also a good idea to coat the inside of the end of the boot that slips over the plug with a thin coat of dielectric grease, available at any auto parts store, to make it easier to remove the boot next time.

Jim Van said:

You need to "screw" it back on, just not "push" it on. It's not a friction fit.

I would remove it again, cut about 1/4 inch off the end of the wire and then screw it back onto the spark plug boot to make certain it is secured properly.

It's also a good idea to coat the inside of the end of the boot that slips over the plug with a thin coat of dielectric silicon grease to make it easier to remove the boot next time.

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Cutting off any of the wire may not be advisable as the length is really tight to begin with. As long as the internals made contact with the spike part of the boot things should be good. It's not just the ST's that have a problem with this, I had a similar problem with a Corvette. The wire separated from the boot and caused a fault code and miss. The first time the dealer tried to just put is back together which did not hold and it came apart again. I ended up needing a whole new plug wire. YMMV.

The cable screws into the spark plug by around 1 inch to be fully seated. Measure and mark the cable at 1" as it is impossible to tell how far you have screwed it in otherwise. I daresay that a decent, firm contact will be made before that. It helps to add some dilectric grease to the outer of the cable or a thin smear of (say) WD40 to help reduce the friction between cable and the inside of the boot.

The other end is a push fit into the coil. That os held in place by a grommit glued firmly onto the cable outer - which is secured from falling out of the coil by a threaded cap.

Much more info and photos are available in an article I put together when a couple of my caps failed. Not all entirely relevant, but there is plenty in there that is.

https://www.st-owners.com/forums/showthread.php?160113-ST1300-Poor-Running-HT-Leads-amp-Plugs-Solved

Jim Van said:

coat the inside of the end of the boot that slips over the plug with a thin coat of dielectric grease, available at any auto parts store

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just make sure it contains at least 60% dielectric

MY dielectric grease is rated at 100 % . I wouldn't use anything less than 100 %.

Byron said:

Cutting off any of the wire may not be advisable as the length is really tight to begin with. As long as the internals made contact with the spike part of the boot things should be good. It's not just the ST's that have a problem with this, I had a similar problem with a Corvette. The wire separated from the boot and caused a fault code and miss. The first time the dealer tried to just put is back together which did not hold and it came apart again. I ended up needing a whole new plug wire. YMMV.

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Probably apples & oranges here. The Vette probably had resistive wire and was molded, not screwed into the boot.

With a ST , we can always replace the wire with some yellow silicone 7mm solid core wire that can be bought by the foot at any good auto parts store. I have a set on my ST1100 & GL1100I.

Jim Van said:

Probably apples & oranges here. The Vette probably had resistive wire and was molded, not screwed into the boot.

With a ST , we can always replace the wire with some yellow silicone 7mm solid core wire that can be bought by the foot at any good auto parts store. I have a set on my ST1100 & GL1100I.

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Yes the construction is different but I was relaying that the ST's wires are already short and cutting any material off may make the wire too short to use.

Byron said:

Yes the construction is different but I was relaying that the ST's wires are already short and cutting any material off may make the wire too short to use.

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I seriously doubt cutting off a 1/4 " will be a problem.