question about piston ring position

[jimspe]

Hello, I am a first timer at rebuilding a mc engine, I have been dragging around with me a 1972 yamaha ct 175 for approx 20 years wanting to someday ride it, I had it running but it was flat in performance so I sent the cylinder out for overbore to accomidate a new .50mm piston and ring set, I have it back from the mach shop and have found that the 2 piston rings are different, one is "wedge" shaped and the other is "square", my quest is which groove does the wedge shape fit in ? After that I can start re-assembly, thanks for any help one might provide,,,,,,,,jim

 

[jimspe]

Ok ,,,,,,,,,, I got an answer about this ,,,,,,,,,,the wedge looking ring goes on the top (upper) ring groove with the writting "UP",,,,,,,,, now I hear that once the cylinder has been bored (.50mm and up) (which mine has been)that the head has to be "bored" ? to match so as to prevent the piston from "slapping" the edges of the head that hang over,,,,,,,,,,,,,,,,, does anyone out there have a shop in mind that does this ? I just spent 8-10 weeks waiting for the cylinder,,,,,,,,,,, thanks ,jimBo

 

[Dave.Smith]

Square cut ring top, beveled ring bottom. The piston has a ring locating pin pressed in to each ring groove. Take a close look at the ring ends - they are notched (for lack of a better word) to match up with the pins.

 

[jimspe]

is that out of a book ? pertaining to the 72 yam ct 175 ? cause I've got 2 answers and now they are opposite,,,,,,,,,,,,,,,,,ugh, thanks ,,jimBo

 

[Jaybird]

I believe Dave is correct.
The beveled ring is the oil ring and should be on the bottom.
I think that the pins located in the ring grooves are off-set from one another, meaning that when the ring is in the correct groove, the exhaust arrow (on the ring) will be pointing to the front of the engine.