To MotoMike
I agree that worn rings are needed to allow that residue build up, but it is just one photo on a website. We are not in a garage and we don't have the full picture.

That is to say, this motorcycle is not typical. It has done 50,000 km in 14 months. We don't know anything about it apart from a few scant facts and one photo, which gives little ground to make any generalizations about this engine. I just don't know enough about it.

To me is it just a small piece of data to make a mental about. These are new engines. We don't how many birthdays they are going to have. The data is still coming in.

Red actually I posted lots of picture. Look on the link on the first post.
I will get home and will take more pictures of the piston.
The piston was deformed and this sized the rings. For short time

I Just emailed the Honda Dealer here in South Africa.

They Use Semi-Synthetic oil for the Break-in process.
As you stated in the beginning of the thread you also had Semi-Synthetic for your break-in period.

Out of every single thread I've read about, the break-in period says NO to any type of Synthetic Oil.

Maybe because the use of synthetic oil made the Rings Seated incorrectly causing the rings to wearing incorrectly cause the oval shape. Meaning there was blow back. making the oil in the Long run degrade Quickly.

To many variables to know exactly what went wrong.

There were no oil degradation, the oil alwas were clean.
Again the gases blown by on 2 sides after the rings sized .
If the rings wouldn't set from day one I would have lots of ash and deposits in every oil change.
And I alway got clean oil except the last oil which I drained before disassembling the engine

Oh, I didn't see that link. You have taken heaps of photos.
The destroyed small end needle roller is definitely the scene of the crime. But what led to its demise is hard to say. It certainly spread around; metal debris everywhere.

Yep and the most intresting is the shredded copper cage and how it hapen?
The cage shredded, the the needles got broken into pieces, and all the needles going below the crank, thepiston to cylinder head Clarence decrease and piston hits the cylinder head.
The piston deformed this coused the rings to size. And this coused the gasses to blow to the oil


That's the chronological order of events

I have to disagree with the last part of your order of events. The combustion gas blow by, as evidenced by the discoloration on the piston, could not occur in the very short period of time (a few seconds, if that) that the crankshaft continued to turn over after the needle bearing failed, and the top of the piston hit the cylinder head (which should have also damaged the valves). This engine would have died almost instantly.

That degree of combustion gas blow by takes a significant amount of running time to build up. I'll say it again... this combustion gas blow by is the result of piston rings that were not well seated during the initial run-in of the engine when it was new.

I'm still curious as to how you are certain that the needle bearing cage was cracked from day one? (sorry, but I have to keep asking this question)

look i stooped the bike because i felt the knock from piston that hit the cylinder head.
evidence for that is the smashed surface near the KYJ and IN on the other side.

you didn't looked at all the pictures in the link, i posting another picture from different angle(which i take from the whole album from post 1).

let say you right about the rings the how can you explain the clean drained oil from previous services?
why the decoration occurred only on 2 sides under the piston and not on the whole diameter of the piston?

i am certain because it shredded the brass cage ,but the needles wasn't worn the bearing contact surface is not worn, nothing only shredded cage which did all the mess.
when the engine is working the cage don't carry any loads. how could the cage be shredded without any significant wear on other bearing components?





now some messurments

PISTON PIN O.D 17.00 mm which is on standard reference of 17.00-16.994, the service limit 16.98
PISTON SKIRT 75.94, service limit 75.89
CYLINDER I.D 76.08 , service limit 76.04
crank shaft to journal bearing O.D 34.000 , service limit 33.975

it looks like the engine would last the weak points is: the piston which coating degrading considerably fast.
and the shims of the valves which all 4 gone offset by 0.05mm

Attached Images

File Type: jpg

PIC00766.jpg (104.2 KB, 79 views)

Sounds to me that Strelok understands exactly what happened, and it doesn't sound implausible at all. Let's hope that the issue here was one cracked bearing cage that eventually failed, rather than Honda having used a whole bunch of bad bearings...or that there is a design defect here that will result in this happening to a whole lot of engines at some point

Dan

From behind my computer hard to judge what happended , you gave a plausible description of the events leading to the failure but from your photos 30 and 39 this piston is not looking good. The photo 39 shows lots of undercrown deposits that are there for a while , they hinder cooling and that may lead to extra piston groove deposits causing the rings to no longer perform their sealing task and cause increase in blowby gasses.

I wonder if the Motul 7100 has been up to its task it's specs are OK for what I could find (API SL , JASO MA) but it's not exactly advertisement the way it made your piston look.

I am interested in the overal cost (ballpark OK) for this repair if UR willing to share.
Richard