Spark plug cap question

[Izzyboy17]

Hello all,
I am working on doing some basic maintenance on my new to me ‘03 1300. Went to do the spark plugs and noticed that somebody that owned the bike previously tried to use pliers or something to pull the cap off of the 4 cylinder. The cap is torn apart where it sits on top of the hole for the spark plug, and the elbow where it connects to the lead is pretty torn up as well.

My my question is looking at the parts diagram, it seems that these caps just screw on to the lead. Do you think it would be better to just replace the cap, replace the cap and lead, or just replace the coil packs altogether (I still need to take off the Tupperware and do a once over on the inside anyways)?

i don't want to leave it the way it is because the cap is so messed up that I'm afraid that water will have no issue getting down to the spark plug in wet weather.

Any my advice is welcome!

 

[Igofar]

The prior owner didn't damage the #4 cap, the plastic cylinder head cover did.
When you pull the plastic cylinder head cover off, you'll notice that it has a grommet that fits down over a post on the engine, however, you'll see that there are (2) loops where grommets could fit.
Only 1 loop is used on the ST1300 and its the empty loop that cuts the rear corner off the plug cap whey you put the cover on and off.
You can fix this by simply taking a dremel tool or snips and a file, and removing the un-used loop. I do this on all the bikes that come through the garage.
This way you can now remove and replace the cover with just one hand or a couple fingers, and, it won't damage the cap anymore.
You may be able to search the forum and find more information about this modification.
If not, PM me a contact number and I'll call and explain in more detail.
You can order a new cap (CAP ASSY., NOISE SUPPRESSOR30700-MCS-G01$21.07) and simply push it back on the wire, and turn it a couple times, no need to remove any plastic to do this.

 

[Izzyboy17]

Thanks for the info. Taking off the loop shouldn’t be a hard task, if I decide to. Never thought it would damage the cap but after your info it makes sense.. It’s good to know the cap assembly just goes right into the wire. When it comes to the plastic it is going to come off either before or after winter anyways. I want to take a look under it all, do a once over, and do a drain/fill on the coolant.

 

[jfheath]

simply push it back on the wire, and turn it a couple times, no need to remove any plastic to do this.

When I replaced mine, I marked the leads where the lead entered the cap and unscrewed. They were buried 1 inch into the cap. It bothered me a bit as presumable the threads cut into the copper strands and chop them off, but I figured - better to have them good and tight so that nothing can shift - so that's how mine went back on. I'm not saying that how to do it, just how mine were then and how they were replaced.

on the inside cover moulding. It is the very first thing I did with my current ST1300 when I got it. Even before calling out the recovery services when I lost drive after just 7 miles. (Clutch lever incorrectly assembled)

 

[roginoz]

I just replaced the caps and leads on my bike. One of the leads was split (probably from forcing the plastic maintenance cover into place) but I thought I might as well do all four while I was at it. At the coil end, there's a collar on the lead that helps to press the lead into place. (It'll make sense when you look at the coil and lead.) At the cap end, you just have to push it on by hand. I found that a bit of silicone dielectric grease helped. The leads are all different lengths, but they're numbered for their respective cylinders. It's an easy job.

 

[jfheath]

At the cap end, you just have to push it on by hand. I found that a bit of silicone dielectric grease helped.

The coil end is a push fit - hence the collar and grommit glued to the lead. It won't stay put without those. The cap end is a screw fit. Silicon grease sure helps overcome the rubber on rubber friction.