Motorcycle Carberetta Problem.

[Jbird]

Hello all.
I have a suzuki bandit 1990, recently aquired. starts well and performs o.k
Q. when the thottle is sharply twisted the engine responds immeadiatly and cleanly. however, when the throttle is closed as quickly it takes several seconds to return to tickover.
All mechanisms are in good order as is the thottle grip and cable. The air box is clean and the filter is good, I have established that there are no obviose air/vacum leaks.
Any ideas as to where to start will be most appreciated.

Thanks

[tonyav]

Check the float in the carb, make sure that it is dropping cleanly IE the mechanism on the carb is working as it should.

[Graham-W]

Remove the slides from the carbs and give them a good polish with Solvol Autosol. Bring them to a mirror finish so they slide back into the carb body easily, even under the vacuum formed when you shut off the throttle.
If that doesn't solve it it's probably best to get your carbs balanced by someone who knows what they're doing. I'd get the carbs balanced anyway as a matter of course.

[Valmave]

Try a new throttle cable.

[jomifl]

Take off the carb assembly and check that the slides return together when you close the throttle and that they all have the same gap between the bottom of the slide and the carb body(ie they are synchronised) when they are closed. You should be able to adjust this with the throttle stop screw.

[Dagman]

I had a BSA a few years ago, similar problem. Eventually found the float had a pinhole in and had petrol inside. Ok when running at speed but when shutting off the throttle was slow to respond, sometimes it would flood.