Can recomend BDK, send them your barrels they have all the machines onsite. both James and Sam are into there 2 strokes in a big way, And have just done my bike, they didnt port anything as such but replated one barrel, honed the other sorted the squish in both heads and put it all back together. Give em a call for a quote sam always answers. they have loads of 2 stroke tunning experiance, and do lots of conversions. mention Me "Jamie" or this site as he knows both well!

Most people (correct me someone) say the 21 is pretty good anyway and just needs a tidy to take all the edges of it.

here: 01508 481713

http://www.bdkraceeng.co.uk/