Oil rings worn
 

Greetings from Spain

I arrived here a couple of weeks ago and noticed a sudden oil consumption on the way. An oil consumption too big to be ignored. Luckily I got some good amigos here and they convinced me to take out the engine using their garage. So I did and I'm glad because a lot of soot (for sure) in the combustion chamber and now that everything is measured by a pro, it turned out that everything else is perfect except the oil rings! They don't seal properly. At first we thought it was the cylinder being oval but turned out it's the other way around. Also not much honing marks could be seen on the cylinder although it's about 7000 km old.

This is not a stock cylinder. It's the Off-The-Road's 104 mm kit accompanied with Carillo's piston and rings. Only about 7000 km ridden after the engine overhaul and the oil rings are ****ed while everything else is correct.

So does the jury here have any other theory for that except bad honing or manufacturing fault with the oil rings? If the mistake was by me, I wish not to repeat it.

Jami

L�hetetty minun GT-N7100 laitteesta Tapatalkilla

It's hard to imagine that a worn oil ring would be caused by you, Jami. If your bike had eaten dirt, the compression rings, piston and the bore would be affected, too.

The soot is a worry, but is a result of excessive oil consumption imo.

7000km is a very short life for non-competition rings. OTR needs to answer some questions, perhaps. Unless you're using very bad oil and never changing it.

What do you mean the oil rings are shot?

1/ Are the oil ring gaps not correct after the 7000kms, were they set at the time of assembly?

2/ Do the oil ring scraper rings have good wall tension?

3/ Was the oil ring expander fitted correctly?

4/ Are the oil drain holes in the piston clear?

5/ Place one oil scraper ring at a time into the bore centralizing the ring with the piston crown then remove the piston & shine a light down the bore, can you see any light past the oil scraper rings?

The scrapers didn't have a good tension and I could see the light past them. I checked the oil ring gaps at the time of assembly but this time I didn't even do it since I could see the rings are so bad. Right now the new parts are in and the engine's back together, waiting to be put back into the frame. As far as I know, I did everything properly at the first time. The oil drain holes I never realised to check but they should be fine since it was a new piston at the time and the consumption started after maybe 3000 km. Now, of course, everything has been cleaned.

No bad oil either, I used Yamalube 10W-40 after break-in of the engine.

L�hetetty minun GT-N7100 laitteesta Tapatalkilla