High revs after revving engine.

[damo1]

Aye all, not sure if this is in the right area but i have a problem that is confusing me.

After revving the engine the idle stays high before dropping off to normal.

Is it running lean at idle??

I thought that if the throttle was snapped shut quickly and the revs dropped below idle then came back up it was running rich, and if they stayed high and dropped back to idle slowly it was running lean

Ive confused myself but i think i'm right????? Maybe someone could confirm it for me??

O by the way its a zxr750.

Cheers damo

[mike-s]

if its got cv carbs then the sliders could be taking their sweet time returning to full extension.
Also when was the last time the carbs were correctly synched?

[Smitty]

if its got cv carbs then the sliders could be taking their sweet time returning to full extension.
Also when was the last time the carbs were correctly synched?

....+1
my thoughts zactly

[netbikes]

yes I think running lean, it is quite often the case, bike is starving for fuel at low speed so it keeps revs hi to bring the fuel from the intermediate jet, possibly a float level issue or maybe blocked idle jets.
As a small test, while it is reving high at idle pull on the choke slowly, a bit at a time, if the revs slow you know it is a lean mixture. There could also be leaks around the rubber air ducts, just spray wd40 or similar on them while it is idleing, you wil probably need to have the tank removed and a remote fuel set up happening to do this successfully. Good luck.
It's a bastard when your bike don't run nice:)

chris

[jap]

Aye all, not sure if this is in the right area but i have a problem that is confusing me.

After revving the engine the idle stays high before dropping off to normal.

Is it running lean at idle??

I thought that if the throttle was snapped shut quickly and the revs dropped below idle then came back up it was running rich, and if they stayed high and dropped back to idle slowly it was running lean

Ive confused myself but i think i'm right????? Maybe someone could confirm it for me??

O by the way its a zxr750.

Cheers damo

Check the simple things first - ensure the rubber grip is not touching either end. If touches it can slow down snap back.

[Kwak addict]

Check your cable routing, turn the bars to full lock either side & see if there's any difference, also give the cables & throttle drum a good lube.

[Gosling1]

sounds like a leak in the inlet manifold rubbers to me......clamps not done up tight enough.