"R" and "RN" markings on piston rings, which goes in which groove?

[segge]

Hi people,

 

I’m installing a TRX450R Piston Kit which comes with the extra ring.

 

The oil ring and side rails obviously go in the bottom piston groove. The other two rings have marks on them, one has an “R” and the other a “RN”. Which goes in the top and which goes in the middle groove? The ring with an “RN” seems to have a slightly bigger gap. Are they different?

 

Thanks

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https://www.thumpertalk.com/topic/778794-trx450-piston-in-a-crf450x/page-2?hl=%2Bpiston+%2Bring+%2Brn#entry9165874

[Qqqqqqqqqqqq]

Read post #28

[Jim Dettman]

The ring with an “RN” seems to have a slightly bigger gap. Are they different?

 

 Understand that rings are *fitted* to the cylinder and you must make sure you have the proper ring gap.   This may require filing of the ring to get the proper gap.

 

Jim.

[segge]

Cool...got it. Thanks guys.