Mar 20, 2007
I have a 2002 kx 250. I want to do a rebuild on it. I can't decide whether to do a single ring piston or just the regular 2 ring piston. What do you think? How much faster does the single ring piston make it? Does the single ring piston not last as long so I will have to do a rebuild sooner? How much longer does the 2 ring piston last over the single ring? Is a single ring piston worth it? Thanks!!!!


Aug 21, 2005
It doesn't make it faster, but it reduces friction and may reduce piston weight, I would estimate a .01% increase in top end HP, and a barely quicker revving engine. Unless you are a top level rider, I don't think that you would notice and improvement, and if you were such a rider, then you would likely have somebody on the payroll making this decision for you.

Of course, you should wait for others to step in here, for I did not take the time to double check my facts before posting this. If I later find that I am incorrect, Eric's book is on the shelf, I will edit this post.


Jan 19, 2004
In my experience the double ring set ups keep the compression at a good level quite a bit longer. Not sure if you would feel any power gain from only having the one ring.
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