Idle rpm influenced by the clutch?

[Dommy]

Hi all.

The idle rpm of my '9 is odd, because when the gear is in neutral and the clutch lever released the idle rpm is at approx 1500 rpm, but by pressing the lever it goes down to a normal 1000 rpm after 3-5 seconds.

It never did this before, but also recently the clutch is very noisy with lever released. Could there be a connection between these two points?

Nevertheless I'll have to deliver to the workshop after 3000 km more and I'll ask to check all this.

The bike is a 2007 with 54000 miles on.

Thanks folks for all input.

Dommy

[UVATom]

They all make more noise with the clutch released. Mine also revs a little higher but not quite 1500 rpms. More like 1200 and around 850 to 900 with the clutch engaged. Every once in a while it will rev up to 1800 but cutting it off and restarting typically clears it up.

[futurR]

This is induced by the ECU when it sees the clutch level is pulled in.

[Metalman]

The idle speed on my 2006 changes when the clutch is pulled in also. There are times when it idles too fast. Sometimes I rev it a bit and the idle will slow down. I would like to have an idle adjustment control.

[frankj]

you can restrict the inlet pipe on the idle control valve, mine,s set at 500
https://www.youtube.com/watch?v=KXN_lFrWjeY

[Metalman]

Thanks,
Can you post information about how to restrict the pipe and where it is?

[frankj]

Thanks,
Can you post information about how to restrict the pipe and where it is?

the pipe goes from the airbox/plenum to the idle control valve iirc, so should be filtered ideally
mine just hangs down near the r/h filter and i had a fuel tap there to alter the flow, i just leave it open now (6mm bore pipe ) and have to blip the throttle for half a min when cold, then it idles at 500 (clutch in or out)

[Bering_C_Sparky]

I know frank has said several times he is doing this, but before everyone starts altering the idle of their bike they may want to read the service manual very carefully.

Suzuki says many times in the service manual not set the idle lower than 900 RPM.

There certainly must be a reason they took the time to point this out in multiple places.

Likely so your oil pressure stays at a sufficient level to keep the bike properly lubed at idle.

Just thought I would throw that out there again so everyone can contemplate the flip side of that coin before trying to do this.

BCS

[cbxer55]

I would actually like mine to idle a little higher. When stopped, if I hold the idle around 1100, that's where the Cobra Tri Pro sounds best idling.

[UVATom]

I agree that oil pressure would be my concern idling that low.

[frankj]

i,m not saying to run at 500, its just my personal preference to hear a big twin chugging
i,m saying you can LIMIT the idle by restricting that pipe, so that the ecu cant physically open the icv to 1200 rpm
if you fit a ( ~ 10mm) bore pipe it will still idle at 900, but wont be able to idle at 1200 any more

[cbxer55]

Thing is, if it's idling at 1200, something's wrong. Usually the only reason they idle that high is because you didn't let the gauges complete their self-diagnosis. Don't start it until the tach goes goes all the way to the right, then back to the zero peg. If I start mine prior to that, it idles high. Other than that, it idles at 900. I want mine to idle higher. The Cobra Tri Pro sounds better idling around 1100 to 1200 than it does at 900.

[meierjn]

Thing is, if it's idling at 1200, something's wrong. Usually the only reason they idle that high is because you didn't let the gauges complete their self-diagnosis. Don't start it until the tach goes goes all the way to the right, then back to the zero peg. If I start mine prior to that, it idles high. Other than that, it idles at 900. I want mine to idle higher. The Cobra Tri Pro sounds better idling around 1100 to 1200 than it does at 900.

Interesting. I wasn't aware of that! Thanks for sharing.

[UVATom]

I have had a tuner on mine for what seems like forever so don't remember the stock bike. I have noticed three things that affect the idle over the years.
1 - Having the rain socks on the spike air filters will cause it to idle high and just removing them doesn't stop it. I have to cut the bike off and restart.
2 - Bad gas will cause it to idle high. I have had it idle at 2k after filling up before and wouldn't stop until I added a fuel treatment.
3 - Hitting the starter and the bike not actually starting will cause it to idle really high on the next attempt. The fuel from the first try is still in the cylinders and the bike puts more in.