I think it's unlikely that the floats/valves/strainer are the problem, but if the carbs are coming off anyway, you should probably check them out. It's not too bad, just a matter of unhooking the floats (held in by a pin) and then not losing the needle valves, which rest on the floats via a tiny metal hanger and drop into the valve seat. Your call though

 

The carbs are currently off the bike and, yes, the pilot jet was blocked (again!). But I found that the strainer for the float valve for cyl 2 (the problem one) is stuck inside the carb body whereas the others have come out with the float valve seat. I've tried a little careful jiggling around to get it out but have given up in the interests of preventing damaging it. I've rinsed it with carb cleaner whilst still mounted in the carb but is there a "clever" way to extract it before I pass that point and move onto reinstalling the carbs on the bike?

 

She's back together and up and running. Phew. Must have been the pilot jet causing the problem. I've also bench balanced the carbs. I know it's not as good as dynamic balancing but probably good enough for what I need for the moment. I'm going to look on the forum to see what other's have done for fitting a fuel filter as I definitely need to stop any further ingress of crud from the tank. I understand the importance of getting the right "size" for the line, but as space seems to be pretty limited around there maybe someone else has found the best one to fit. Maybe it's simply one for the earlier model which has the fuel pump but I think the fuel line is longer on that version and so offers more opportunity to fit the filter. Anyway, thanks again for the pointers on pilot jet, strainer, filter etc etc. Only problem is now that the bike's fixed, I have no excuse for not taking the missus shopping.....

 

While you're out, pick up some Scotch Brite.

 

Timbuktoo, yeah right. I'll get some scotchbrite while I'm out alone. Don't want the missus to see me buying it and thinking I've suddenly developed a fetish for washing the dishes!