Hi guys,
which piston ring goes on top the green one ?
which one goes on bottom ?

please help Frank 

Keystone ring goes on top. Wont fit in the lower groove.

Keystone is the green one 

 

Gray ring 
green ring 
which goes where ?

A Yamaha Keystone piston normally (always?) has a "K" stamped into it.    You don't want to put a keystone ring into a standard groove piston.

Yamaha rings normally (Exception: Dykes top ring) have a tiny "1" (top) and "2" (second) stamped into the top edge near the ring gap if they are different.  Check for that.  You'll likely need a magnifying glass.  

There are so many mixed up ring sets and piston/ring parts changes over the years, it pays to be careful. 



 

Thanks you are awesome!!

Do I use the expander rings ?
how do they go on underneath the main rings ?

Here's a quote from the (piston and) ring master, Enduronut:

"The CT2 & CT3's models use expander rings underneath both top and bottom rings.

The yellow marked one goes in the top groove.
You'll also notice that it's a bit narrower then the bottom expander."

 

Keystone rings wont fit into the wrong piston groove.