The ones for the SA model of the NS400R are close though...

In any case, the NS400 is not 400cc. It is 387cc or 373cc for the SA model.

It is just a case of Honda rounding up the numbers.....

373/3 is the same as 249/2..............

I know this doesn't mean the pistons are exactly the same but they must be at least similar given how closely related both models are.

MC11 pistons must be available from somewhere...

Just trying to help with what little info I know

All the best

philandhisjag
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No bikes at the moment, looking again
Dreaming of another NSR!!!!!
1989 Ford Thunderbird