Thank you both for the replies.
The engine is a 600 and is late Shipley model with distributor ignition. I’m using a 200 main jet at the moment and the oil i’m using in both the oil tank
and the premix is Millers classic 2-stroke oil which they say is specially formulated for classic 2-srtoke car and motorcycle engines.
The premix in the petrol tank has been thoroughly mixed at 50:1 ratio. I am using BP ultimate petrol Brian as you suggested.
I took it for a short run up the road this afternoon and it did improve a little but it still needed choke to run and was popping and banging and generally being rather erratic.
I have checked all the inlet manifold and the tranfer port covers for air leaks but can’t see any, – all the gaskets are new and have been carefully fitted and all the ‘mating surfaces’ have been checked for flatness. I will check again however when I get a chance. Could the air slide or the needle need changing ? It currently has the standard 6/3 air slide and a No: 6 needle which is on its middle notch.
I am hoping to get this bike sorted in time to bring it to the Scott weekend at Shuttleworth which is not far away !
Thanks for your help.
Mark
