Hi,

try www.ns400r.co.uk - there is a parts list on there, from the Honda microfiche, there is also a forum and if you put 'piston' in the search you'll see it's been discussed a lot!!! Solution vary from geting 64mmpistons and reboring/replating, to CR125 barrels and pistons (not seen one of these on the road yet...but I know of 2 being made, one is quite near me...

You can get B grade NS400 pistons from David Sliver in the UK, but the 400 is a 57mm bore and the 250 is (I think) a 56mm bore. But you may find an NS400 barrel and piston on ebay, that would be the cheapest way to get the thing running.

Cheers, Mat.