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drifting piston ring?

1549 Views 14 Replies 9 Participants Last post by  jbranson
What can cause a piston ring to drift off the key? A friend of mine has an old kawi 350 triple, and he's running suzuki pistons, with the barrels bored out to match. Not sure what size the pistons are. His bike developed a "ticking" nose last night with only 80 something miles on the new top end. We found the the right piston had drifted off the key. We put it all back together again making sure everything was were it should be. When we kicked it over the nose was gone. But as soon as we started the bike it came back right away. Any thoughts???
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aircooled two strokes have pinned piston rings (perhaps the key he is referring to but I think he is talking about the land) to keep the gaps from lining up while the bike is running. Two stroked run such a loose tolerance (as compared to 4 strokes) that the initial break in is vital to engine life.


First which ring drifted? The first thing I thought of was the gap tolerances are out (if a ring has too much gap then as soon as you fire it it will want to fold on itself), the second I though is that the ring itself is out of spec and you need a new ring, Third I thought is that the ring land is damaged. Once the ring has "drifted" or otherwise bent then it is junk and you need a new ring - you can't use the old one.

What model suzuki is he using pistons from? T250? GT380?

Edited by - Geeto67 on Apr 24 2007 2:37:37 PM
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