thanks for reply guys,i am near lowestoft/beccles area and thanks or offer paul,after it seazed up [firstday/2miles down the road]i rebuilt it the next day with some old spare pistons i got with bike,it was all done ready to start,but as ididnt want to mess it up i [folishly] gave it to local shop to CHECK over,2 weeks ago,they stripped it back down and said we need to order gaskets [head/base/exhaust] then we will check oil pump etc and you can have it back,i went in today to collect it and they say they cant get head gaskets so tonight i rang jap4performance and he had the hole kit instock so as i just want the dam thing running i orderd it,but as i said he only has one type listed for mc18,but my luck it wont be right, my barrels fitted i think are c as bottom one has c cast on base of barrel and b stamped on and bottom barrel also has c cast on it and nothing else,i under stand that the smallest piston will fit all three [a,b,c,]and be ok on clearence, but what if the only kit listed is the largest piston cos it wont fit b and c barrels,so,i just want the bike right and running,
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NSR250 MC18