throttle

[nudedaytona]

I altered the idling speed on the bike today (Aprilia rs250). It was set on about 2800 rpm, so I brought it back down to about 1400, as the manual says.

One thing I have noticed is that when I release the throttle (Say from 5,000 rpm) it will go down, then pause somewhere between 2,000 - 2,500rpm, go up slightly, and then drop back down to 1400 rpm. Is this normal, or does it indicate a problem, like with the spark plugs or something?

[imdying]

You may have a float height that is too high, possibly because the float has been incorrectly set, or because a needle and seat is leaking. Or the choke mechanism may be sticking. Problems with sparkplugs usually make it idle lower or not at all.

[nudedaytona]

Thanks, cheers mate you're a lifesaver. I'll try fiddling with the choke first, to see if that's it.

[imdying]

Well, choke might do it, generally it indicates something is letting air in when it shouldn't. Make sure the manifold that goes over the reed valve, and onto the back of the carb, is tightly on the carb. You might want to try running it with the airbox off, and making sure that the slides are returning correctly. There's a number of air bleeds in those carbs, maybe even an electronically controleld one, any of those could give similar trouble I would expect.