This might be a new one here...carbon fouling UPDATE on page six

[baddean]

To the collective minds that reside here. ( I could not find this in a search).
The background first, please.
Just got home from a 3400 mile trip out west to Colorado. Bike ran great. Straight home on the slab in 100 degree temps and cruising at 80-90. Washed the beast and parked her. Next day, well:(
2008 C14 26,000 miles. Flies out. PC3. Premium gas from multiple locations. Regular oil changes. Ridden hard enough that I should not be being told what I am hearing.
Started the bike up next day and it made a noise (hiccup?) and quit. Tried to restart and nothing but crank. The electronic dash then acted up (zeroed both trip meters, lost the whole TPS screen (as in gone), imobilizer flashing fast). Cranked but no starting. OK, figured battery. 3 years old. Voltage drop when cranking (12.5 to 11.0 then 11.4). Ordered and received a Shorai and installed. Now it cranks for a while then starts. And sounds like a can of rocks being shaken. Whoa!.
To shorten this, I took it to a dealer (where I bought it and they know me). They now have the head off of it and are telling me that the combustion chambers are so carbon fouled that the pistons are hitting the fouling ( hence the banging, rattling noises) and that some of it may have broken off and gotten lodged under one of the exhaust valves and damaged it.
Now I've been around internal combustion engines since I was 12 years old and understand that carbon fouling can be a problem in many instances but..... a modern 4 stroke fuel injected engine used the way we use them??
Within 26,000 miles??
WTF??

Any ideas, no matter how radical, will sound sensible right about now.
Thanks, in advance, to the collective minds here for any input you might have.
Dean

[B.D.F.]

There may be a build- up of carbon in the head of your bike but it is not likely that it caused the sudden noise and then noisy (mechanically noisy) running. It sounds more like something like a timing chain skipping a tooth or some similar type of problem. Of course if that is what the dealer found then that is what they have to report but it does not mean it (the carbon) was the initial problem.

As gasoline does not leave much in the way of deposits, it would almost have to be motor oil causing that amount of fouling; was the bike consuming crankcase oil? Had you noticed any change in idle characteristics before the 'big noise'?

Brian

To the collective minds that reside here. ( I could not find this in a search).
The background first, please.
Just got home from a 3400 mile trip out west to Colorado. Bike ran great. Straight home on the slab in 100 degree temps and cruising at 80-90. Washed the beast and parked her. Next day, well:(
2008 C14 26,000 miles. Flies out. PC3. Premium gas from multiple locations. Regular oil changes. Ridden hard enough that I should not be being told what I am hearing.
Started the bike up next day and it made a noise (hiccup?) and quit. Tried to restart and nothing but crank. The electronic dash then acted up (zeroed both trip meters, lost the whole TPS screen (as in gone), imobilizer flashing fast). Cranked but no starting. OK, figured battery. 3 years old. Voltage drop when cranking (12.5 to 11.0 then 11.4). Ordered and received a Shorai and installed. Now it cranks for a while then starts. And sounds like a can of rocks being shaken. Whoa!.
To shorten this, I took it to a dealer (where I bought it and they know me). They now have the head off of it and are telling me that the combustion chambers are so carbon fouled that the pistons are hitting the fouling ( hence the banging, rattling noises) and that some of it may have broken off and gotten lodged under one of the exhaust valves and damaged it.
Now I've been around internal combustion engines since I was 12 years old and understand that carbon fouling can be a problem in many instances but..... a modern 4 stroke fuel injected engine used the way we use them??
Within 26,000 miles??
WTF??

Any ideas, no matter how radical, will sound sensible right about now.
Thanks, in advance, to the collective minds here for any input you might have.
Dean

[baddean]

Brian,
Thanks for the reply. No oil usage at all. The engine idled and ran beautifully before this. And when was the last time you heard of a modern motorcycle engine being used normally having a timing chain skip a tooth, during startup?
After doing some research on gasoline and additives it turns out that todays gasolines do, in fact, leave a lot of deposits in the fuel system and combustion chambers due to the gas companies putting less and less additives in the fuel to meet government minimum mandates for these additives.
I found that on some of the sports car forums this carbon build up is a big problem.
Dean

[jjsC6]

Brian,
Thanks for the reply. No oil usage at all. The engine idled and ran beautifully before this. And when was the last time you heard of a modern motorcycle engine being used normally having a timing chain skip a tooth, during startup?
After doing some research on gasoline and additives it turns out that todays gasolines do, in fact, leave a lot of deposits in the fuel system and combustion chambers due to the gas companies putting less and less additives in the fuel to meet government minimum mandates for these additives.
I found that on some of the sports car forums this carbon build up is a big problem.
Dean

That is the first I have heard that.  It will be a good learning experience to all of us.  Have you actually seen it with the heads off yourself yet?

[VirginiaJim]

Wow....I wonder if these bikes run a bit rich as the tail pipes are always covered in soot.

Dean, do frequent the same gas company or do you mix it up a bit.  I know I've had problems in vehicles running Exxon gas with carbon buildup so I stopped using them some years back.  Also, have you ever used any FI cleaner in it?

[Mister Tee]

You have a PC3 installed, so presumably you are using something other than a stock map.  These bikes appear to run pig rich to begin with - if you run an even richer map, that could be a problem.

Also, "premium" fuel could contribute somewhat to the problem if it's significantly greater than the specified 90 octane.

[B.D.F.]

Early Kawasaki automatic cam chain tensioners had a nasty tendency to fail to extend and allow the chain to skip one tooth (if you were lucky), and Yamaha FJRs are showing a tendency to do the same thing after racking up some miles. I am not claiming it is in any way common but that problem you have is not common either.

Building up sufficient carbon deposits to cause mechanical interference in the combustion chamber, from gasoline alone, in less than 30K miles just does not seem reasonable to me. Heavy carbon deposits usually show symptoms long before they cause the valves to strike the pistons. Again, I am not saying that that could not be your problem but it strikes me as a rather remote possibility.

Finally you said everything was fine up until a bang and the engine stopped and then the trouble started. That does not sound like a slow, progressive situation like carbon build-up but it does sound like something mechanical, such as a cam chain skipping a tooth. It isn't even that I really suspect the cam chain either, I just cannot think of anything else that would cause your sudden mechanical interference in the combustion chamber.

In direct answer to your question, yes, I have heard of modern motorcycle engines having timing chains become miss- timed. To turn it around, have you ever heard of a modern, gasoline fueled, and correctly running engine having mechanical problems due to carbon build- up?

Brian

Brian,
Thanks for the reply. No oil usage at all. The engine idled and ran beautifully before this. And when was the last time you heard of a modern motorcycle engine being used normally having a timing chain skip a tooth, during startup?
After doing some research on gasoline and additives it turns out that todays gasolines do, in fact, leave a lot of deposits in the fuel system and combustion chambers due to the gas companies putting less and less additives in the fuel to meet government minimum mandates for these additives.
I found that on some of the sports car forums this carbon build up is a big problem.
Dean

[gonzosc1]

Early Kawasaki automatic cam chain tensioners had a nasty tendency to fail to extend and allow the chain to skip one tooth (if you were lucky), and Yamaha FJRs are showing a tendency to do the same thing after racking up some miles. I am not claiming it is in any way common but that problem you have is not common either.

Building up sufficient carbon deposits to cause mechanical interference in the combustion chamber, from gasoline alone, in less than 30K miles just does not seem reasonable to me. Heavy carbon deposits usually show symptoms long before they cause the valves to strike the pistons. Again, I am not saying that that could not be your problem but it strikes me as a rather remote possibility.

+1, tensioner would be my guess to start but even then i think its rare to just jump a tooth all at once, every one I've heard of always lead up to it with noise starting softly and building up to a jump and rattling loudly. but theres a first for everything.
 did you see the head yourself yet? carbon build up that bad would mean something is not right else where. I'd like to see that.

[wally_games]

Don't want to turn this into a "gas thread", but I always run premium to meet the 90 minimum manufacturer's recommendation. I'd rather run 89 mid-grade for the cost savings, but... ...

Anyway, I was told by a GM service manager awhile back that you should ONLY run Shell, Chevron, or Quik Trip (one of the least expensive in our area) gas in your vehicles. At the time, they were the only ones that were rated by the federal government to be "tier 1" gas. Actually, when I switched to regular grade QT gas from mid-grade Mobil and Exxon in my cage, my gas mileage went up by 8%. And that was after 55,000 miles of running the more expensive stuff.

Ok, back to the engine failure discussion... ...

[Fretka]

That sure sounds like a valve/piston touch scenario, and these are interference timing engines. Having been around bikes a long time I have seen the progress of cam/drive/primary chains come from "sure to fail to just about set and forget". Having said that, cam chain tensioners are more likely to cause this to happen than the chain itself. But all this is conjecture, you need a second opinion from a disinterested source BEFORE any more work is done to that engine. Unfortunately some info has been lost by dis-assembly but a "forensic analysis" will tell the tale.

While carbon buildup will certainly cause damage, that would be very easy to determine as the combustion chamber would be similarly encrusted. Also should cause pre-ignition prior to failure. That whole idea of modern fuels causing engine failure do to carbon build-up seems pretty lame to me as the industry would never tolerate widespread warranty claims because of common gasoline stocks or additives failing to meet industry standards.

Nothing special about your engine design or your use of it or the fuels that are widely available to you, if there were, we would have seen it elsewhere.

Caveat: I am not the last word or fount of all knowledge but this is my best guess and no, you can't always trust the shop.

Fretka

PS I have not imagined or worked out all the possible scenarios of VVT failure but this feature COULD cause issues such as you are experiencing.

[Son of Pappy]

From left field, I wonder if the cats may be partially plugged, causing a richer then normal condition?  What comes in must go out and since a stock US bike has no 02 sensor, the injectors will continue to pump the same volume, regardless of airflow.  Ever see a car pumping smoke only to find out the air filter was plugged?  Ever see a diesel with a dirty filter?  Reduced flow results in rich conditions.  Regardless, I'd sure use this as an excuse to upgrade to a full system

My .02 in this game of guesses.

[B.D.F.]

The tensioners in C-14's are 'semi- hydraulic' and depend on engine oil pressure to force them outward and tension the chain. When starting they are quite loose and there is often a distinct cam chain rattle in the engine for perhaps 3 or 4 seconds until the tensioner moves. This is the time that I would suspect the cam chain would jump, if that is actually what happened. Again, pure speculation on my part.

Brian

+1, tensioner would be my guess to start but even then i think its rare to just jump a tooth all at once, every one I've heard of always lead up to it with noise starting softly and building up to a jump and rattling loudly. but theres a first for everything.
 did you see the head yourself yet? carbon build up that bad would mean something is not right else where. I'd like to see that.

[B.D.F.]

Not to step on your toes, and just in the interest of accuracy: tier 1 gasoline is defined by a consortium of auto manufacturers, not any government. And Mobil Exxon fuel, at least in some areas, is a tier 1 fuel (it was not always though).

Again, just to comment, I don't think you can find bad enough fuel anywhere in the US that would allow the engine to keep running and yet build up that much carbon in less than 30K miles. The only problems that I know of that anyone has had with any C-14 that could be directly connected to fuel were clogged fuel screens in the fuel pump, and those were always caused by contaminated fuel, not just fuel that was not the best available. Put another way, all fuel available is pretty good stuff IMO.

Brian

Don't want to turn this into a "gas thread", but I always run premium to meet the 90 minimum manufacturer's recommendation. I'd rather run 89 mid-grade for the cost savings, but... ...

Anyway, I was told by a GM service manager awhile back that you should ONLY run Shell, Chevron, or Quik Trip (one of the least expensive in our area) gas in your vehicles. At the time, they were the only ones that were rated by the federal government to be "tier 1" gas. Actually, when I switched to regular grade QT gas from mid-grade Mobil and Exxon in my cage, my gas mileage went up by 8%. And that was after 55,000 miles of running the more expensive stuff.

Ok, back to the engine failure discussion... ...

[B.D.F.]

Outstanding Chet! Great idea... "Honey, I have to upgrade the exhaust, we don't want another one of those episodes, do we? It really is a safety issue in the end...."

ROFLOL

Brian

<snip>

 Reduced flow results in rich conditions.  Regardless, I'd sure use this as an excuse to upgrade to a full system

My .02 in this game of guesses.

[baddean]

Hey All,
Thanks for the replies thus far.
Went to the dealership today to see for myself and sure enough the combustion chambers are carboned up pretty badly. The number two cylinders exhaust valves are stuck open due to loose carbon bits caught under them. During a leak down test they leaked like a sieve. All intake valves are seated tightly. Two other exhaust valves are leaking very slightly which could be fairly normal or they could have some debris under them as well.
We'll know more once the valves are out of it.
I took the head to Bore Tech because Bill is a friend of mine and I trust him with the job of sorting it out.
To answer some of the other questions:
Brian,
It really wasn't a "bang' more of a loud click. So no indication of something catastrophic.
 No I haven't heard of modern sportbikes having a carbon build up problem either. Neither has anyone else I know. But, now I know that it is, in fact, the current problem. Just don't know what caused it except it being fuel related.
Back in the sixties (maybe earlier) the Gov mandated that gasoline companies put additives (with a minimum standard) in their gas that would inhibit combustion chamber deposits. It didn't work very well then.
Today the gas companies still have a minimum standard but is even less (50%) than it was in the beginning, so it is even less effective now. They are now more concerned about emisions than keeping your engine clean, except that Shell seems to be attempting to address the issue in their fuels.
Cam chain, tensioner, and timing were all ok.
Mister T,
The PC3 is programmed for the flies out and stock pipe. No soot in the tail pipe and I averaged 38 MPGs for the total Colorado trip while getting an average of 43MPG on the slab alone. So no excessive fuel consumption here.
Virginia Jim,
I buy fuel at a lot of different stations because of my travels on the bike but, I do buy most of my gas at one particular station (Marathon) when I am staying around locally. I guess you could say that most of my gas is purchased there. And I do run FI cleaner through it about every 4-5000 miles just like I do on my other FI bikes. The FI cleaner, however, won't address the combustion chamber issue.
STP has come out with a product called STP Total Fuel System Cleaner that is supposed to address the intake valve and combustion chamber deposits. I figure that if STP has developed a product for this, there must be someting going on with the gasoline we are buying. Doing a search for this issue I found quite a bit of info on the problem.
The BMW M5 forum and a couple of other sports car forums that I found seem to be discussing this like it is an up and growing problem, especially among vehicles with engines that have very close tolerances and tight squish clearances (our bikes??)
Gonzo,
I will have some pics that Bill at Bore Tech will take for me (I didn't have my camera, doh!)
The dealer had already cleaned up the piston crowns, but said that some of the buildup had to chipped off as it was hard caked on the piston. Some of it came loose in little flakes.
Fretka,
Interesting that you brought up VVT failure because at some point we are going to check that out. Also there is no indication that the valves and pistons contacted one another.
Son of Pappy,
Doh!!! I haven't yet checked the air cleaner. I'll run that "full system" idea past the financial advisor. Hah!
The head should be done sometime next week and the bike back together after ??
That's about all I have for now.
Will keep you updated as to how this is going.
Dean

[kdm]

This is probably out of left field ,but this thread has me wondering  -maybe it would be a good idea to set up a water injection
system for my 14 .You older mechanic -type guys might remember . Just a small water tank with a hose going to a tiny orifice
placed somewhere in an engine vacuum line . An adjustment can be placed on the hose to control water volume. 

This may sound like backyard hocus pocus , but it works well for carbon removal from the combustion  chamber. Small amount of water is harmless ,but shines the top of the piston like new. Of course , you have to fill the tank occasionally.

Even seen the more adventurous techs pour a small stream of water directly into the carb throat- - quick clean!

[B.D.F.]

I do not believe a malfunctioning VVT could cause mechanical (piston to valve) interference. The change in timing occurs at high speed but the relative relationship between piston and crankshaft remains the same; if the valves clear the pistons at redline and max. cam advance, then they will also clear at idle or even when the engine is turned by hand while still at fill camshaft advance (assuming something is broken in the VVT control mechanism).

Greatly advanced timing will cause the engine to start and run poorly (symptoms the same as a very high overlap cam) but only due to gas flow inside the engine, not because of any mechanical problem caused by the cam timing.

Brian

<snip>

Fretka

PS I have not imagined or worked out all the possible scenarios of VVT failure but this feature COULD cause issues such as you are experiencing.

[B.D.F.]

Given that info., maybe there is nothing wrong other than excessive carbon deposits.

Your logic and facts about gasoline are all correct I believe but still, if this were a general problem we should have heard about it long before now. You do not even have a lot of mileage really (some have topped 100K miles with C-14s, and mine is coming up on 72K miles) for such accumulation. It just does not seem reasonable to me that gasoline is the root cause of your carbon problem (thinking out loud here, not trying to argue).

The only engines I have seen carbon excessively are small utility engines when they are used for many hours; engines are similar to 'lawn mower' engines but used to power generators or air compressors for commercial companies. The source of the carbon in those engines is motor oil, not fuel. They have lousy oil control in the cylinders, lousy crankcase vacuum control and usually horizontal cylinders with splash lubrication.

If the inside of the exhaust ports are covered with flaky carbon and / or wet with oil, it is a sign of valve stem to head clearance issues, usually a worn valve guide bushing. As you are sending the head out for rebuilding that condition should be found during inspection.

The only other thing I can think of is a batch of contaminated gasoline from a distributor. Not one tanker full but an entire storage container. That way you might have gotten quite a few loads of contaminated fuel from the same station over time. ??

This is an interesting situation. Best of luck with it and please let us know what you find out.

Brian

Hey All,
Thanks for the replies thus far.
Went to the dealership today to see for myself and sure enough the combustion chambers are carboned up pretty badly. The number two cylinders exhaust valves are stuck open due to loose carbon bits caught under them. During a leak down test they leaked like a sieve. All intake valves are seated tightly. Two other exhaust valves are leaking very slightly which could be fairly normal or they could have some debris under them as well.
We'll know more once the valves are out of it.
I took the head to Bore Tech because Bill is a friend of mine and I trust him with the job of sorting it out.
To answer some of the other questions:
Brian,
It really wasn't a "bang' more of a loud click. So no indication of something catastrophic.
 No I haven't heard of modern sportbikes having a carbon build up problem either. Neither has anyone else I know. But, now I know that it is, in fact, the current problem. Just don't know what caused it except it being fuel related.
Back in the sixties (maybe earlier) the Gov mandated that gasoline companies put additives (with a minimum standard) in their gas that would inhibit combustion chamber deposits. It didn't work very well then.
Today the gas companies still have a minimum standard but is even less (50%) than it was in the beginning, so it is even less effective now. They are now more concerned about emisions than keeping your engine clean, except that Shell seems to be attempting to address the issue in their fuels.
Cam chain, tensioner, and timing were all ok.

<snip>

That's about all I have for now.
Will keep you updated as to how this is going.
Dean

[CrashGordon]

The only other thing I can think of is a batch of contaminated gasoline from a distributor. Not one tanker full but an entire storage container. That way you might have gotten quite a few loads of contaminated fuel from the same station over time. ??

Brian

He said he usually buys gas from one station when he's home. I'm racking my brain trying to figure out how significant carbon fouling can occur in a short time due to gas and I can't really come up with anything. I can definitely see it happening over a long period of time. Perhaps that Marathon station just sells bad gas and after many tankfulls it finally added up to too much gunk?

[baddean]

Hey Brian,
I'm with you all of the way on this regarding the gasoline alone being the root cause.
The only other thought I came up with regarding fuel and or ignition efficiency was that during the trip home from Colorado I was caught in slow moving (crawling, paddle footing) construction traffic in 100 degree temps for about an hour east of St Louis (that seriously sucked). Also, we were out there for the Pikes Peak International Hill Climb and at the end of the race it took almost 4 hours to get us off of the mountain, again idling. For 4 hours, except those times when we could turn off the engine and coast downhill. Don't know, just trying to rationalize this carbon. Makes no sense.
The exhaust ports do have some light black chalky discoloration but nothing that would be considered abnormal for an exhaust port.
The spark plugs look pretty normal as well.
My bad, I haven't checked the air filter yet. I will do that when I take the head back to the dealer.
While there was a layer of carbon buildup across the entire combustion chamber the worst of it was on the piston crown on the intake side where the piston has a lip, if you will. The rest of the piston crown is flat except there. Carbon had built up at the base of that lip significantly, to the point of being able to be chipped off in a whole piece. Carbon was built up on the head portion of the chamber in the corresponding location. The number 2 cylinder is the culprit at the moment and the carbon "chunk" was broken loose in that chamber. The other 3 chambers still had the carbon "chunk" in place before they cleaned them out.
Again, I will only have pics of the head because the dealer has already cleaned up the pistons.
Crash,
I do buy most of my local gas at the same station, but I put that same gas in 4 other motorcycles (3 of which are vintage and ridden regularly), 2 cars, and a lawnmower.
I'm not convinced that this a gas issue only. You are correct though that I could have gotten a bad slug while on the trip home from Colorado.
Now the air filter is bugging me.
Here is a link the the STP product that I think I will look into when this is settled.
http://www.stp.com/products/fuel-additives/complete-fuel-system-cleaner/
I'll update as I know more,
Dean