Stalling

[Phil C]

Okay thanks everyone. I've screwed in the pilot screw until the engine ran unevenly, then out until similar, and found a position of max revs in-between. Then adjusted throttle stop screw for a steady tickover. The result is the screws are in the same positions as before, exept the throttle stop screw is a quarter of a turn further in. Even just that little bit makes a difference. Also there's no rise in revs when handlebars are  turned. So hopefully that's it sorted, and my education has moved on another small step. And it's been fun of course. Thanks again. Phil

[Phil C]

By the way, just in case you're interested, my carb is a Concentric 626. I think that probably wouldn't be what was originally on the bike (1965 B40F) when it rolled out of the factory. Maybe would have been a Monobloc? Phil

[Phil C]

I think the bike was originally despatched to the MOD for the Auxiliary Fire Service, but don't imagine that would have made any difference to what carb was fitted at manufacture?  Phil

[Mike40M]

I think the Monobloc was superseded by the Concentric in 1967. On the bikes I know about anyhow.
It's said that it improved fuel consumption, otherwise no big difference in performance. The slimmer Concentric made it easier to fit two side by side on twins.