In the world of Pre65 trials the Wassell carbs don't have a good reputation.Rapid wear of the body and slide make it difficult to maintain accurate mixture control at low revs.(Just like the old original Concentrics)We always use the Amal premier units with a hard anodised slide. Even they can benefit from a couple of tweaks when new,but once set up correctly they last well.
I'd save up and buy the correct Amal unit,it will always be right then and the "experts" won't be always telling you its not original.
As an aside on new concentrics it is important that the flange nuts are only just "nipped" up as any more force distorts the body and the slide will stick. A few times at Pre 65 scrambles and Red Marley we have sorted bikes by just loosening the flange nuts half a turn!
Richard
