All things are not equal-spark plugs

[RBMann]

2000 S @ 76,000 miles w/lazer chip and Power Commander, all else is stock engine wise.

Four years ago, while riding the Continental Divide, it started running a little rough and would die at idle. Thought it was a tank of bad gas and altitude. After cleaning the throttle bodies everything was fine again. This year on the way to TOR, the issue resurfaced. Cleaning the TBs did not help.

Left plug looks normal to me but the right plug looks rich or has a mis-fire. Right plug is slightly loose in spark plug wire connector and has some black coloration on the cap.

Swapped plugs and the dark plug is still the right cylinder. Swapped spark plug wires at the coil end only(right wire is still powering the right side) and it is still the right side.

Spark plug wire needs replacement?

[chewie]

Nice close up RB, sorry I can't help with the plugs. Is that a marble bench top? What is that, you got marble bench tops in your garage? Damn!

[RBMann]

Yes, but fake.

[chewie]

ah

[cageyar]

The plugs show evidence of ash deposits, the yellowish, granular stuff around the electrode and on the end of the threads. The condition is usually referred to as ash fouled.
The problem with ash is that it is non-conductive, so as they accumulate, you can experience a slight mis-fire condition. They can come from the burning of fuel additives, oil consumption (oil burning) and/or fuel quality issues also maybe compunded by a lean running condition.
Are you using any unusual amounts of oil and been on the road and had to use some suspect fuel?
I'd replace the plugs and while doing it, consider getting some quality iridium plugs.

[lht]

Autolite 3923 will help. Why are people so cheap about replaceing them?

[cageyar]

Originally Posted by lht

Autolite 3923 will help. Why are people so cheap about replaceing them?

As Bill Murray said to Dan Akroyd while taking a swig from a bottle of blackberry brandy in Ghostbusters, "I don't know......I don't know."

[RBMann]

They are 3923s and if I swap sides with just the plugs then their condition changes. The right cylinder always looks rich. The bike uses 1 qt. of oil every 2000 miles and a ran a bottle of Techron injector cleaner through it.

[cageyar]

Originally Posted by RBMann

They are 3923s and if I swap sides with just the plugs then their condition changes. The right cylinder always looks rich. The bike uses 1 qt. of oil every 2000 miles and a ran a bottle of Techron injector cleaner through it.

A full bottle? If it was a 12 oz. bottle that was too much. If it was a 20 oz. bottle, yikes! If by chance you dumped a full bottle of Techron into one tank of fuel, there is the source of the ash deposits. This is a case where more is not helpful.
You should apply Techron per the instructions which approximately, an ounce per gallon. Using it any stronger than that is not necessary.
And a full quart of oil consumption between changes is a fair amount of oil burning-that with the Techron overdose is enough for ash deposits.
I'm wondering, since the issue is restricted to the right cylinder, if you have a consumption issue in that bank.
Maybe a leak-down test is in order.

[roger albert]

That oil consumption while not horrible, will certainly give a bit of extra ashing.

Could be any number of different things. Valvelash, compression, plug wires, coil caps, TBs, airleads.

If you're not starting with new plugs, then a good ACCURATE read is hard.

Gotta chip away at causes one by one. Though it wouldnt' have been my first guess, the fact that the system once responded top cleaning is worth re-examining (if you're sure it _really_ did)

[cageyar]

Roger,

What's your feeling on dumping the whole bottle of Techron into one fuel tank?
If it was a twelve ounce bottle that's 2 to 2.5 times more than instructed, if it was a 20 ounce bottle, it could be 5 times as much as recommended.
My experience is that over dosing fuel additives generates ash deposits.

[roger albert]

Too much, and could cause problems with rubber bits, and combustion.
I really wish there was a good way to measure oil consumption left/right independently.
I doubt it's even. Done leakdown and compression tests and the other basics yet?
They'd be helpful.

[RBMann]

Techron was done in several tanks and cleaning the TBs did not help. Roger might be right, that the prior cleaning really did not fix anything. The oil use goes up with temp. and speed. In 1600 miles to TOR it used a quart. Temps. were above 90 F. and the speeds were 80+ MPH. Getting home the temps. were in the 70s, at lower speeds and it used a quart in 3000 miles.

Set up a test rig and the spark does not look that great with the right looking even weaker. More checking this weekend.

Thanks!

[cageyar]

Originally Posted by RBMann

Techron was done in several tanks and cleaning the TBs did not help. Roger might be right, that the prior cleaning really did not fix anything. The oil use goes up with temp. and speed. In 1600 miles to TOR it used a quart. Temps. were above 90 F. and the speeds were 80+ MPH. Getting home the temps. were in the 70s, at lower speeds and it used a quart in 3000 miles.

Set up a test rig and the spark does not look that great with the right looking even weaker. More checking this weekend.

Thanks!

Those ash deposits on the plugs in the right cylinder are coming from someplace.
90 F. and 80+ mph is somewhat severe conditions, but a leakdown test, especially for the right bank is in order. A quart in 1600 is above average consumption in my view and oil burning can produce ash deposits.
Good luck and let us know what you find.

[ExarKunONe]

I dont know about BMW but Yamaha and Suzuki both say that anything less than a quart of oil per 1000mi is normal oil usage.

[roger albert]

Must check compression too though. When cylinder goes barrel shape, much of leakage is below TDC, and the leakdown test with rings statically seated in the narrower bore at TDC will not show the blowby. Leakdown also not good at catching worn guide/stem which causes a slow seal of valvefaces (assuming they're ok) but doesn't show up in the static leakdown test. Both tests useful, but you need both together to get a good picture.

I've had oil consumption near that high, but only at about 10 degrees and 10mph higher, and sustained, and not quite that high even then.

[RBMann]

Continued story-

Did a compression test and the readings were 160 and 170.

Replaced coil and plug wires with know good ones. Installed new plugs and here are the photos after about 100 miles. I still have the rough idle and mis-fire under light throttle.



I removed the injectors but I don't have the knowledge to judge them. Test sprayed but I don't know what to look for or if I was using the right method.



Cleaned what I could and re-installed. I will run it to see how it feels then swap the injectors side to side and check the plugs again. If the problem moves then I know it is the injectors.

[SergioK]

My 'new to me' 2002 S had a somewhat rough idle too. After some investigating, I discovered that one of the previous owners had performed a very bad cannisterectomy. I pulled all the hoses and rerouted them properly. While I was in there I also drilled the tank fill and pulled the top air bladder inside the tank (then bent the inner tube upwards). After all was said and done the bike now idles perfectly. Also, IIRC, the right plug will always show more soot because the airbox intake or somesuch is on that side.

[cageyar]

Good update.
I'm sure you checked, but is the any issue with the air filter condition or air box restriction in any way? Any chance your PC settings were altered or lost it's settings? My original comment was about the ash deposits but the 1100S is not my machine so I'm going to have to defer to more experienced members on this unit.

[RBMann]

Originally Posted by SergioK

Also, IIRC, the right plug will always show more soot because the airbox intake or somesuch is on that side.

Do you mean the oil breather?