Coils and Caps

[Mashermoto]

Problem is with a 78 XS1100E

Symptoms:
After washing with a garden hose, the bike won't start Again It will run after it dries out. This last time I blew the plug caps and plug wires out with compressed air, sprayed contact cleaner in those areas and greased them with dielectric connector grease. It started right up.

However, what happened next registers fairly high on my freak-o-meter After the dielectric treatment I took it out for a test drive around the neighborhood. As soon as I got out the driveway, it started running like on two cylinders. I pulled over and placed the transmission in nuetral and it reved up cleanly. But when I would pull the clutch lever in it would act like running on two again. What the hay bales would cause that

So I pushed it home and let it set for a few hours. Then no more problems...just needed to dry out somewhere other than plug caps and wires

More symptoms:
A few days later I took it out for a ride. It ran fine to my first destination stop, which was about 15 miles. A few hours later I started the engine and headed out on an open rural streach of road running through the gears with authority After 5th gear I slowly backed off to a speed the County Sheriff would appreciate and the engine started feeling like it was running on two cylinders again It did this for about 4 miles. Then after stopping at the first stop sign it cleared up. I suspect cylinders 1 and 4 were cutting out because those two spark plugs are a bit darker. 1 and 4 plug caps also have high resistance readings...see below for more information.

What I found today:
After setting for several weeks I took a closer look. Here is what I found.

Primay coil meter reading is 2.3 ohm for both 1-4 coil and 2-3 coil. Hmmm...should be 1.5 ohms. Were those replacement coils I bought for a 81 model

Seconday coil reading (without spark plug caps on the secondary wire) is 15.5k ohms for 1-4 coil and 15.1k ohms for 2-3 coil. Hmmm...isn't that susposed to be the reading with caps on the wires

Plug cap reading is 6.7k ohms for #1 and 8.4k ohms for #4. That seems a bit excessive

Plug cap reading is 5.2k ohms for #2 and 5.2k ohms for #3. That's more like it

I don't know if it helps, but the coils are marked on top as 12V CM12-08 91.

Reading through old posts I know there can be other areas causing the problem, but if you guys will allow I would like to eleminate the coils and caps first.

So, first things first. Are these reading telling me I have bad coils and bad #1 and #4 plug caps

[natemoen]

I would certainly replace the caps on 1&4! 15k is what you should have without the caps, 25k with the caps. It also should say on the coils if they need the resistor in line.

[bikerphil]

Sometimes when washing the bike, water can enter the harness down by the neutral light switch (left side under the shifter) causing loss of two cylinders.

[ViperRon]

NKG Plug caps actually can be dissasembled from the plug end. When they have been in the bike for a while they can build up slight corrosion internally. They tend to hold moisture and can cause the same symptoms you have. I have had a cap that would not work and had about 15K reading taken it appart soaked the inside and the internal resister spring and cap screw in Tarnex cleaned dry reasembled with dielectric grease and had them run fine. You also can clip off about 1/4 inch of the end of the cable and rethread the cap back on with some dielectric grease then use high temp silicone to seal the rubber arround the caps. This works fine for about a 4 to 5 months of driving and then you can have the same issues again if exposed to water.

You can replace all the parts new and still after washing still have the same issues but cleaning greasing and sealing has helped my condition.

[Mashermoto]

Natemoen: yes, the coils say to use external resistor.

Bikerphil: interesting about the neutral switch. I did have to repair some insulation damage to the neutral switch wire. When i get it running i will spray water on the switch and see what happens.

Viperron: I'll strip the caps down and clean them up. It won't hurt to try. The caps are OEM. So there is a resistor spring behind the screw?

What do you guys think about the high primary coil reading? Should be 1.5 but is reading 2.3.

[bikerphil]

interesting about the neutral switch. I did have to repair some insulation damage to the neutral switch wire. When i get it running i will spray water on the switch and see what happens.

It's not so much the neutral switch wire, but the P/U coil wire splices which are in that general area of the sheathing. The moisture can enter where the neutral wire exits the harness and get down to those factory splices causing a short.

[Mashermoto]

Just writing to close the chapter on this story. The executive summary is a pulser coil was bad.

The detail is I replaced the OEM coils with Dynatek DC-1 coils and Accel 8mm yellow copper conductor plug wires and four new NGK caps. I also bypassed the coil resistor. Used lots of silicone spray and dielectric grease on everything. The setup is extremly sassy looking, but didn't solve the problem

I performed a pulser coil test at the TCI as instructed in the shop manual and one pulser coil tested bad. I swapped them out with a spare set. Now the plugs don't spark...they throw flames

While I was at it I gave the coils an extra boost of current by cleaning out the kill switch and dosing it up with dielectric grease.

So far so good. The bike never started so easy or ran so smooth

[bikerphil]

You got it fixed, that's good... New coils help tremendously.

Where is your chin fairing, didn't you have one on that bike?

[trbig]

That looks like the same fairing and mirrors the Limie bike has on it.

[bikerphil]

That looks like a Maier fairing. In my previous post, I meant to say chin scoop, that mounts down below the headers.

[Mashermoto]

Biker,


I still have it, but never used it.

I had it mounted for a Kerker 4-1, but the exhaust system I got off Ebay was so full of rust holes I couldn't use it.

The Mac 4-2 headers I'm using now won't allow it to mount

TR,

You are correct sir...I have a maier quarter faring with the same mirror as your Lime bike.

BTW, anybody know where to get one of these front fenders This picture is a Bob Jones bike, but unfortunately he passed away just as I was starting my build.

[Mashermoto]

Wait a minute TR...I just took a closer look at your Lime bike...you got one of those fenders

OK...fess up...where did you get it

[natemoen]

Wait a minute TR...I just took a closer look at your Lime bike...you got one of those fenders

OK...fess up...where did you get it

The Lime is a Bob Jones bike! So he got it from the same place as Bob

[Mashermoto]

Nate...oh wise one from the west...you're response begs the obvious...where did Bob get his

[natemoen]

Nate...oh wise one from the west...you're response begs the obvious...where did Bob get his

Who knows, maybe his wife knows.