Problems at high speeds.

[mr self destruct]

ok got confused untill i read previous posts
basicly they let air in while your throttle is closed (pilot)(sorry if im writing this in basic terms but its easier for newbies in the future)
so if your float needle valve is open and letting in fuel your main jets are effectively closed so this is the easiest route for your fuel to flow through
- 90% sure its a jammed float needle problem
could just be a bit of crap made its way through if not its a new needle valve assembly 5-10 quid on ebay but make sure you replace the whole bit and not with (ooh there was a bit of that in a spares box)
hope its making sense i am better at doing than explaining (which is why i fail written exams lol)

I took the bottom off one of the carbs tonight and I think I see what you mean.








If the float valve doesn't seal then the fuel will be forced up the left most jet of the theee in the picture, spilling out of the left hole in the first pic. I think. So I'll order four of those valve kits and see what happens.