New piston rings: Which groove?

In what order are the piston rings installed? I have new rings. One has a bevel on both outside edges and is dull silver on the face that touches the bore. The other ring is black all over. I know that the letters (RN) should be uppermost. Which one goes in the first groove (top) and which one goes in the second? The two old top rings seemed to be identical and gave no clue.

The two rings that go top and bottom of the third piston groove appear to be identical and it seems that they can be installed either way up. Is that right?

I'm in a bit of a rush here folks, so if anyone can help me I'd very much appreciate it.

 

Hopefully this will help:

- All original and aftermarket piston rings are "directional"....the top and second ring are designed to be installed in a certain orientation. Check your service manual for the proper installation procedures. Most factory oversize rings have their oversize dimension stamped into the top ("up") surface of the ring; standard sized rings typically do not have any such markings. 2nd (center) rings are always installed with their wider, "scraper" edge towards the bottom of the piston:

UP
___
|____\

DOWN

 

The two top rings in each set are marked 'RN'. They are original Yamaha standard size rings. I have checked my manual (Haynes) which is of no help, otherwise I wouldn't be asking here.

Are you saying that the bevelled ring is the top one? What about the two rings in the third groove?

 

I've looked again, and if there's a bevel on one of the rings it isn't discernable, even with a loupe.

 

The rings with a bevel on the outer diameter are the 2nd (center) rings....they fit into them middle piston ring land.

The top ring should have a gently radiused outer face:

UP
____
|____)

DOWN



The 2nd ring should have either a sharp beveled outer face (as illustrated in the previous post) OR a squared outer face:

UP
____
|____\

DOWN


or/:


UP
____
|____|

DOWN



Bottom rings are actually 3-piece, and upper and lower spacer and the "corrugated" scraper. You should install the corrugated section first, and then by hand (only.....don't use a ring expander tool) fit the upper and lower (they're the same) spacers above and below the scraper. Make sure that these spacers can rotate freely after installation.


Top ring and 2nd ring end gaps should be oriented 180* opposite of each other. Upper and lower bottom ring spacer end gaps should also be oriented exactly opposite of each other, and these gaps should be offset a bit from the gaps of the top two rings.


Original (Yamaha) rings have their OVERSIZE dimension stamped into the top face of the rings; standard rings typically do not. However, there may be other markings (such as the RN you mentioned) in the ring faces.

 

chacal, that's spot on. Thank you. I shall print out your post for when I go back to the shed in the morning. It's now nearly 11 pm here.