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.

To Andy: The problem was that the 2 intake ports on the one side does line up with the piston edge when at the lowest. At that same stage the 2 intake ports on the opposite side are lower than the piston edge.

But thank you, I would just then leave it just like that and work on the squish.