I run mind hard (well, I did until I took it off the road a couple of years ago to restore it), and would generally look at doing the rings around 2500-3000km, and the pistons at 5000-6000km. Pretty unscientific, but it worked for me, and my '21 knocks out just under 67rwhp, so it's a little stressed. (I also have a tendancy to run it quite on the edge, jetting-wise!)
I've seen (stock) raggy MC16s and MC18s in Asia with 25-30,000kms on that appear to have never even had the motor apart... in fact, they appear to have never even seen a service! LOL
I'd love to know what the actual highest mileage NSR250R is.
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Andy.
NSR-WORLD.COM
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