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CB750K7 piston rings

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UKROBK7:
Just bought 4 sets of OEM rings from Dave Silvers.  They are NPR (Nippon Piston Ring Co).  In each set there is ring that has a bright edge and a ring that looks to be plain cast iron.  The bright edge one has a "1N" mark stamped on it and feels slightly rounded (no sharp edges).  Am I correct in thinking the bright edge one is the No1 (compression) ring and should be installed with the marking facing the top, the plain ring would then be the No.2 ring?

Anyone had any experience?  I can't find any info on the NPR site and am waiting a reply from D.S.

Rob

Spitfire:
Hi Rob, many years ago I asked about piston ring markings on the US site, here's the answers that I got.
http://forums.sohc4.net/index.php?topic=14205.msg139736#msg139736

Cheers

Den

UKROBK7:
Just had the reply from D.S, it confirms what I thought! :-

The rings should be installed onto the piston thus;
 
The thick ring with the silver/grey edging and the "1N" marking goes on top. The "1N" mark faces upwards. As a general rule, any writing on rings always face upwards.
 
The thick black ring goes second.
 
The remaining 3 rings form the oil scraper which goes at the bottom, the  2 thin rings sandwich the serrated ring.

So away I go!!

Rob

david451:

--- Quote from: UKROBK7 on July 01, 2011, 03:21:52 PM ---Just had the reply from D.S, it confirms what I thought! :-

The rings should be installed onto the piston thus;
 
The thick ring with the silver/grey edging and the "1N" marking goes on top. The "1N" mark faces upwards. As a general rule, any writing on rings always face upwards.
 
The thick black ring goes second.
 
The remaining 3 rings form the oil scraper which goes at the bottom, the  2 thin rings sandwich the serrated ring.

So away I go!!

Rob

--- End quote ---

Just remember that if there is a ridge on the top of the bore then standard rings can get broken if you don't hone it off, normally you would fit ridge dodgers, they have a recess cut out the top of the ring to miss the wear ridge. It will run but the first time you give it wellie the rings will break.

Bryanj:
In 30+ years the only Honda i ever found with a wear ridge was a PF(I think) 50 ($ stroke) with 90+ thousand on it

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