Cylinder scoring and general frustration.

[niclpnut]

250 miles after a hone, ring examination, head clean up (valve lap, decarbon etc.) 1100ES which was prompted by some oil burning Oil was changed after initial 20 miles of break in, and I was getting ready to change it again.

After pulling the clutch, oil pump, flywheel and checking the ignition advancer I still haven't found an identifiable cause to intermittent engine whine/whirring which as close as I could identify was coming from the lower half of the engine. I had also noticed some white smoke/oil burning after the bike had warmed up some. After a stop it was really apparent.

Today I decided to pull the top end. journals and everything look good. No excessive carbon on valves, and no oil seepage from stem seals.

Pistons 1&4 / 2&3 were at same deck height so no twisted crank. Only a light build up of carbon on the crowns which almost completely wiped off.

Removed the jugs. Pistons looked really good. Very clean below the rings. No real evidence of blow by. No ring damage.

Hone pattern was still quite visible, however, I'll be damned if almost every one had some signs of vertical scoring with 3 being the worst:



After the hone I scrubbed with soap and water to make sure it was all clean upon reassembly. Never ran without the pods installed. Rings were installed properly and no visible damage. The cylinders were well within the service limit after the hone, and the pistons were basically brand new according to the measurements.

Pulled the filter and then the pan to check for metal/debris and couldn't find any. A closer exam of the skirts show some corresponding vertical marks.

Typically it's dirt/grit in the chambers that causes scoring, but everything was really clean upon installation.

Compound this with the engine noise and I'm getting a bit miffed

Only thing left to do is see if these marks will hone out, which I'm doubting, and pull the block and split the cases to see if I can find the cause of the noise.

are there any other methods for checking the crank without splitting cases?

Rant off.

Nic

[rapidray]

"Ring examination"? Does that mean you did or did NOT install NEW rings? Did you clean out all the carbon in the ring grooves before you reassembled it? Ray.

[niclpnut]

Ray, the rings only had about 2k miles since the first time I had the engine apart. I pulled and remeasured all the rings, and cleaned the grooves of all the pistons.

Just got done with the flex hone and the scoring is def too deep.

Waiting for payday and I'll see about those jugs.

I'm at a stand still atm. Don't want to split the cases right now. Decided to halt progress and tear into my 1100E for the mean time.

Nic

[chef1366]

You checked the ring gap?
Those pistons were rocking. Did you get hot? Are the piston skirts collapsed?
I've seen that with extreme hear or not enough ring gap.
Rings weren't upside down?
You can check the play on the rods without splitting the cases.

[hampshirehog]

You checked the ring gap?
Those pistons were rocking. Did you get hot? Are the piston skirts collapsed?
I've seen that with extreme hear or not enough ring gap.
Rings weren't upside down?
You can check the play on the rods without splitting the cases.

I reckon that's along the right lines - has all the hallmarks of the rings being too tight. That looks 'halfway' to a piston seizure.

[niclpnut]

You checked the ring gap?
Those pistons were rocking. Did you get hot? Are the piston skirts collapsed?
I've seen that with extreme hear or not enough ring gap.
Rings weren't upside down?
You can check the play on the rods without splitting the cases.

Yeah I rechecked ring end gap after i had removed them from the pistons to clean the ring grooves. Both loose and installed.

Everything measured out within tolerances.

The hottest it has ever read is right about 230 without an oil cooler. I don't let it sit and idle excessively. My plugs were slightly on the rich side which leads me away from believing I had a fuel mixture issue. I'm running a DJ 3 with K&N pods. 50 pilots, needles second from bottom. 1150 cams.

Skirts are straight, just some vertical score marks that I would assume would correspond to the bore marks. Both the cylinders and pistons were mark free with a good hone on the bores and everything free and clean as far as I'm aware.

Rings installed correctly with the "N" up.

I'm a bit at a loss heh.

I'll check the manual but obviously there shouldn't be any up-down play from the rods on the crank. But, how much lateral play is allowed?

Nic

[hampshirehog]

Don't beat yourself up about whether you cleaned everything properly. Those marks don't look like they are caused by dirt / grit etc but more like a partial seize (almost as if you caught it just as the engine was about to make that dreaded 'mwaaah' noise).

Just grasping at straws but was the oil level ok, decent oil, oil control rings fitted properly?

[niclpnut]

yeah as far as i know everything was ok.

Nic

[tatu]

That does look like its really dry, when you stripped it did it feel squeeky clean as you ran your finger over it?

[niclpnut]

That does look like its really dry, when you stripped it did it feel squeeky clean as you ran your finger over it?

Ya Know I cant really recall.

Nic

[Big Jay]

Skirts are straight,

Nic

Skirts are not supposed to be straight. They should have at least .002" taper. If they are straight, they are junk.

[niclpnut]

My bad. Poor word usage. They haven't collapsed at all. Have a taper.

Nic

[Normk]

Hate to ask, but any chance you installed the pistons and rings dry of oil? They need to be dipped or coated with engine oil before installation and have adequate oil, usually a spuirt, on top on assembly.

What did you use to pre-lube the pistons & cylinder walls?

Any chance the pistons were reversed on the rods? Reversing will move the thrust side offset to the front and increase piston skirt pressure against the cylinder wall.

I assume the scoring was only on the thrust side? That is to say, the scoring is only on the front sides?

A long idling period with seating rings, especially with low idle speed may contribute to over heating and scoring. The heat produced by freshly honed cylinders is quite substantial. This isn't as evident with a liquid cooled engine as with air cooled but we used to notice substantial heating when running in freshly overhauled marine engines. It was often necessary to reduce power for substantial periods until the engine was broken in.

That's a heart breaking development so hoping someone with sharp eyes finds the definitive cause.

HIH

Norm

[elrico]

Info. from old book..".Engine Runs Hot:a modern motorcycle engine in good mechanical condition,correctly tuned,and operated as was intended,will rarely experience overheating problems.However,out-of-spec conditions can create severe overheating that may result in serious damage. Overheating is difficult to detect unless it is extreme,in which case it will usually be apparent as excessive heat radiating from the engine,accompanied by the smell of hot oil and sharp,snapping noises when engine is first shut off and begins to cool. Unless the motorcycle is oerated under sustained high load or is allowed to idle for long periods of time,overheating is usuall the result of an internal prob.Most often it's caused by a too-lean fuel mixture.remove the sparkplug(s) and read/compare to chart..If too-lean condition is indicated,check for intake manifold leaks.The carb.jetting may be incorrect but this is unlikely if the overheating problem has just developed(unless,of course,the engine was jetted for high altitude and is now being run near sea level).Check the slide needle in the carb(s) to make sure it has not come loose and is restricting the flow of gas through the main jet and needle jet. Check the ignition timing; extremes of either advanced or retard can cause overheating. Piston Seizure and Damage :... Piston seizure is a common result of overheating because of ... alum.piston expands at greater rate than a steel cylinder. Seizure can also be caused by piston-to-cylinder clearance that is too small;ring end gap too small;insufficient oil;spark plug heat range too hot;and broken piston ring or ring land" . from old book,for info. only,passed along,thinking about your situation.dont know what, if any applies ..sorry about engine.

[niclpnut]

Hate to ask, but any chance you installed the pistons and rings dry of oil? They need to be dipped or coated with engine oil before installation and have adequate oil, usually a spuirt, on top on assembly.

What did you use to pre-lube the pistons & cylinder walls?

Any chance the pistons were reversed on the rods? Reversing will move the thrust side offset to the front and increase piston skirt pressure against the cylinder wall.

I assume the scoring was only on the thrust side? That is to say, the scoring is only on the front sides?

A long idling period with seating rings, especially with low idle speed may contribute to over heating and scoring. The heat produced by freshly honed cylinders is quite substantial. This isn't as evident with a liquid cooled engine as with air cooled but we used to notice substantial heating when running in freshly overhauled marine engines. It was often necessary to reduce power for substantial periods until the engine was broken in.

That's a heart breaking development so hoping someone with sharp eyes finds the definitive cause.

HIH

Norm

I thought back about installation and I did coat the cylinders and pistons with oil. Maybe not as much as I did the first time around, as I got the base gasket pretty oily. I didn't squirt any oil on the crowns of the pistons once the jugs were seated.

Only thing I can think is that I didnt get the bores completely free of debris after the hone, but I scrubbed them down with a brush and sudsy/soapy water. <shrug>

Just waiting on some cash, then I'll probably hit up Rapidray for a set of standard bore cylinder jugs he has.

Nic