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Wrencher Extraordinaire
2005 K1200LT
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Discussion Starter #1
Steve R brought Dragon Fly over today to find out what was going on. The bike was running fine and had sat for a year before he bought it. He noticed the oil consumption was up but it was running great.

The dealer did a compression/leak down test and #3 failed. We were hoping for some stuck rings but alas she is in need of a new engine.

Pulled the cylinder head and all looked well there. Valves were in tact and none were burned. The piston looked to be missing a bit of material at the bottom. We were still hope full for an easy fix but noticed the NakiSil coating was worn off and there were groves in the cylinder wall.

Now remember she was running great just burning abit too much oil when you look at the pictures. The rest of the cylinders and pistons were fine in fact you could still see the cross hatch in the walls on 1,2 & 4.
 

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What a shame. Unless the piston just chipped off, looks like a small steel particle or rock got in there.

On another note, that is one reason I wanted a "brick" bike, they double as a great engine stand for top end or big end access.:)
 

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Not too hard to imagine things coming apart with a max RPM accel with that type of damage.
Surprised it would not run a bit rough.
Good catch! I probably would have rode it until it stranded me on the side of the road.
 

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Haven't been into mine, but can the cylinders be resleeved or have the nikasil resprayed? I know my niece works at a machine shop for the largest airline in the world and they plasma spray all kind of engine parts and junk like that, but I do not know if that sort of thing can be done to a BMW block. Would be worth looking into before buying a new engine/block.

Sorry to hear about your trouble and hopefully you'll be back on the road soon.
 

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Wrencher Extraordinaire
2005 K1200LT
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Discussion Starter #5
Steve has a lead on the engine out of his old bike that was totaled so there is no "new" in the works. This had been like this for several thound miles based on what I saw on the side of the piston. Just another tribute to the ability of the brick to withstand just about anything and keep going.
 

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jzeiler said:
Steve R brought Dragon Fly over today to find out what was going on. The bike was running fine and had sat for a year before he bought it. He noticed the oil consumption was up but it was running great.

The dealer did a compression/leak down test and #3 failed. We were hoping for some stuck rings but alas she is in need of a new engine.

Pulled the cylinder head and all looked well there. Valves were in tact and none were burned. The piston looked to be missing a bit of material at the bottom. We were still hope full for an easy fix but noticed the NakiSil coating was worn off and there were groves in the cylinder wall.

Now remember she was running great just burning abit too much oil when you look at the pictures. The rest of the cylinders and pistons were fine in fact you could still see the cross hatch in the walls on 1,2 & 4.
How many miles on this engine? Any theory as to root cause? I would suspect detonation, but hard to know for sure. It also seems to have a lot of carbon on the pistons compared to other fuel injected engines I have had apart. Is this typical for the bricks?
 

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Voyager said:
How many miles on this engine? Any theory as to root cause? I would suspect detonation, but hard to know for sure. It also seems to have a lot of carbon on the pistons compared to other fuel injected engines I have had apart. Is this typical for the bricks?
107435. At least that is what my brain is remembering after a good night's sleep. The LT engine is designed to run rich, so the carbon load on the piston heads or the cylinder head did not suprise me. I think the problem is/was a piston with a manufacturing defect not a detonation issue. Dave Shealey had a detonation problem and it affected ALL the pistons not just one.

The piston goes with me to the dealer this week and we'll see what the guys in the shop think.
 

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About that carbon load, any way to keep it to a minimum?
In my early years we used a bit of H2O to keep things on the upper end clean.
They're were things like methanol injectors ect.
 

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Not that I know of and why? These motors and their predecessors have a habit of going hundreds of thousands of miles without ever having to tear them down.

One of things that I forgot to mention in my previous post, was looking that the cylinder head there was a light brown ash colored spot in the middle of the head on cylinders 1,2 and 4 and thought what is that. It wasn't until I woke up this morning that I realized it was the spark plug. :eek:
 

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Wrencher Extraordinaire
2005 K1200LT
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Discussion Starter #10
Steve,

The more I think about it the more I am conviced it was something that got dropped in the intake the last time the TBs were removed. Logic makes sense that it would bounce arond in the cylinder and settle at the bottom. Thus the hole in the piston. I'll shake out the exhaust and see if I find anything. Could have been a small screw or rock. Anything bigger would have really done some damage based on the piston to combustion chamber clearance.
You saw how I filled those opening with paper towels. Well I also use a vacuum on them as well before hooking the TBs back up just in case something did fall in.
 

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I've never had the throttle bodies off. The question is were they off some time in the past before I got the bike?

And wouldn't you have expected to see the tips of the spark plugs damaged if something had been dropped down in there? I didn't see anything on the tip yesterday and there was definately wasn't any damage from the set I pulled out when I got the bike.
 

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Wrencher Extraordinaire
2005 K1200LT
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Discussion Starter #12
Judging from the condition (excellent) of the breather tubing I suspect that when that was installed is when it happened. Long before you got the bike. Just a small rock would have done it. Still I would be interested in what the dealer says. Oh the oil level in the sump was below the top (bottom?) of the oil filter. I could see the flats. Any luck with Tony yet?
 

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Not yet.
 

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John

Kind of hard to see what the failure mechanism might be - with all the carbon at the failure site. It seems to look like classic detonation fracture - but could also be foreign material - like you suggested.

Was premium fuel always used or was regular also used?

Jim
 

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Detonation can and will light or burn carbon and chip and dislodge it, or fracture the piston.

I would love to see that piston cleaned up.

I have always figured the LT would carbon easily due to the way the motor sits. And it going pig rich on full throttle.

Myself, I use Sea Foam pretty regularly 1 oz to the gallon. I know the spray fog from Sea Foam, through the throttle butterfly's while running, on a v-twin will clean the pistons all but spotless, and clear mosquitoes for miles.

I also know back in the day they used water like was mentioned.

What lead you to the leak down/ compression test? You said the bike was running fine?

Just curious if that should be put on a list at 75,000 or 100,000? I mean how else would you pick that up other then oil use?
 

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I think there are shops that can do just that, but how do we get the bore back to the size it needs to be after the work is done. Plus to have that done would mean more down time. I'm already about 13,000 miles behind on my average for the year, so I'm looking for another motor. We may rework this one to have as a spare and the again, maybe not.
 

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I took the pistion into the dealer this morning. Looking at it dirty they said detonation problem. They then voluntarily cleaned it up for me. So, Lee, ask and ye shall receive.
 

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Steve_R said:
I took the pistion into the dealer this morning. Looking at it dirty they said detonation problem. They then voluntarily cleaned it up for me. So, Lee, ask and ye shall receive.
Unless they cleaned this with a hammer and chisel, I would say FOD is the root cause.
 

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Nope, it went through the chemical wash to clean it up.
 

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Steve_R said:
I took the pistion into the dealer this morning. Looking at it dirty they said detonation problem. They then voluntarily cleaned it up for me. So, Lee, ask and ye shall receive.
The marks on the top of the piston could be from when the rings started to break up as the piston burned. My engine also has excessive leakage on # 3 cylinder (30%) past the rings. It's been that way for over 65,000 miles & the last time I looked at it with a bore scope the piston looked fine.
 
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