Harold wrote:I was just wondering about this as both barrels measure the same and was wondering if there isn't something one can do to fix it. The squish on these barrels are around 1.3 -1.4mm so I would just do something about that, take it down to 1.1 because I am running on AVGAS witch is over a 100 octane. Sorry for the simple question, I am also still on the learning curve and would just like to have a perfect NSR250 MC21SE.

If the squish is 1.3-1.4mm are you sure you're not mixing SP spec cylinders (marked L1,L2 or L3) and R spec heads (marked KV3H)?

Stock NSR parts (either matched R cylinders and heads or SP) tend to measure up around 1.2mm squish.
The usual trick of R cylinders and SP heads measure 1mm squish which is OK on 97ron fuel if you're careful with your jetting.

Much tighter than that seems to cost power (in my experience) even if you do have the fuel for it.
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