just cleaned out carbs and now it runs and idles, on/off choke.

but if i give it some throttle it revs up pretty normal but when I drop the throttle it takes like 10 secs for it to idle back down. any ideas?

What bike are you asking about

If it's got carbs then you have an air leak.

1978 xs400-2e, its got carbs.

ok lets hope for airleak i have the gas tank off and was using a gatoraide bottle as a gas tank, and put electrical tape on the vacuum nosel on the carb boots. hopefully that is the problem.

Hopefully i get this right! What you're calling the carb boot, we in England are used to calling the inlet manifold. This considered, have you checked the gasket between the 'carb boot' & the head? On some models it's a paper gasket, on others it's a rubber O ring gasket. sometimes it may be that simple. Alternatively check the 'boots' from the airbox are seating properly, even after tightening the jubilee clips around those 'boots' either side of the carb.

tank didnt help.

ok inlet manifolds. mine are like a round tunnels that have flanges to screw into the cylinder heads, behind these are like thin tin plates.

ok i let check the airbox boots as well.

checked all around the airbox boots and into the inlet manifolds, didn't see any gaps. So i lit a smoke and none of the smoke seems to be getting sucked in or blown away.

i went back and just gorilla tightened everything and it seems a lot better, thanks.

Could be your mixture settings, if you have had the carbs off it might just be that the carbs need balancing and the mixture adjusting.

I know that on my bike (FJ1200) if the bikes too rich it will take its time coming down to Idle, and if its too lean it stalls.

Hope this helps.

Adam.