new ring installation question?????

[thriller]

I am re-ringing a 98 wr 400 and the new yamaha piston rings are two different colors. One is black/grey and the other is a dark tan color. What ring goes on the top? ? thanks very much

[Rip Wheeler]

Well, usually the cast iron ring goes in the second slot, I suspect the back one will be the cast iron. The chome ring goes on the top. Look for a small ID mark near the ring end gaps, these will go up. Locate the end gaps at 10 or 2 oclock or 8 and 4 oclock, avoid them over the piston pin and at 6 or 12 oclock. Now of course, I suggest getting info from someone looking at a manual. But I suspect it will be pretty close to my explanation.

[Hamish]

Well, usually the cast iron ring goes in the second slot, I suspect the back one will be the cast iron. The chome ring goes on the top. Look for a small ID mark near the ring end gaps, these will go up. Locate the end gaps at 10 or 2 oclock or 8 and 4 oclock, avoid them over the piston pin and at 6 or 12 oclock. Now of course, I suggest getting info from someone looking at a manual. But I suspect it will be pretty close to my explanation.

Yes the chrome ring goes on the top.

Yes, the ID mark goes to the top.

As for locating the end gaps, I personally don't bother because the rings do rotate as the engine runs. Make sure you check the gap on all the rings, including the oil control rings. More than likely they won't need fileing, but always check first. To do this, install a ring in the barrel, then using the piston in your hand, push the ring about 1" down the barrel and check the gap using a feeler guage. The spec for the 426 is 8-10 (service limit 22 ) thou for the top ring and 14-20 (servive limit 33) thou for the 2nd ring and 10-20 thou for the oil control rings. I wouldnt imagine the 400 being much different. Since you have the feeler guages out, you might as well measure the ring side clearance to make sure the piston isnt stuffed. The 426 spec is 1.2 - > 5 thou. Hope this helps.

Being an old 400, if it has the stock barrel with a few miles on it your end gaps may be slightly larger.

[thriller]

As it turns out the rings are different in thickness and could only go one way. thanks