First the good news – my 251 is Ulez compliant (£175 less in my pocket though)
The less good is that the substituted Japanese carburettor with which said Ulez compliance was obtained appeared good to start with but has become problematic – in fact it became very difficult to get a stable tick over and smoked more than MZs usually do!
My solution is going back to the drawing board and renovating the original BVF 30- N- 3-1 carb using a supposedly identically one I had tried earlier but which is inferior overall in metal quality and fit.
My question is about whether a) the pilot air screw absolutely needs an o- ring as neither the original, nor the ‘not so cheap’ “identical” substitute had one. Also there seems lots of different views about turns out for both the pilot and the bypass air screws – any thoughts on this are very welcome. The 251 has done about 32k since new in 1990.
Hopefully if all sorted and passes MOT I may see some of you at the ACE cafe for Red Oktober meet on 13th October.