Idle Won't Lower Below 1150 rpm.

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I had my idle set to 1100 rpm. The other day I noticed that it was idling at 1500 rpm. I was able to adjust the idle back down to about 1150 rpm, but it will not go any lower? Any ideas what could cause this?

Thanks,

 

[jmgrif]

Not sure but it could have something to do with a vacuum leak?

 

[Sully1300]

Maybe two things: 1) If you have a power commander then it may be on the fritz like mine just did. I unhooked it due to fueling issues and now the bike runs beautifully. I'll be returning the pcV for a new one. 2) Your idle screw may have backed all the way out. Lift the tank and watch it screw all the way back in. Neither of these issues will throw up a computer problem.

 

[ionbeam]

You need to do a TBS again, the problem is the position of the sync screws. The throttle bodies may be in sync but the over all screw settings is wrong. The idle adjuster screw that Sully mentions is a Gen II thing.

 

[Chiefblueman]

Sounds a little suspicious your idle would increase to 1500 by itself in a short period of time. Whatever you do, don't keep cranking the idle speed adjuster out looking for a lower idle speed. If it comes unscrewed from it's bracket deep within the throttle linkage it can be a real bitch to get it screwed back in.

Sounds like a good time for Fred's totally unauthorized TBS. https://www.fjrforum.com/forum/index.php?showtopic=127426

This should re-reference the throttle bodies and bring your idle adjustment screw back into play.

 

[Pepperell]

What you do depends on the weather. If you lived up here in New England you'd just say "1150? Close enough!" and fix it after the snow flies. Wouldn't want to lose any diminishing riding time. But I see you're in FL and just coming into the riding season so you'll likely fix it now. ;-)

 

[Queensland Ken]

Do a search on RadioHowie's post on the fast idle circuit.

There are 2 idle circuits, the cold / fast idle and the warm / normal.

The fast idle is under and behind the throttle bodies, you need about a thin 14" screwdriver to adjust it.

Maybe the fast idle valves are not seating back into the throttle bodies, from cold / fast idle to the warm / normal idle state.

A very simple check to do is to move the plate the activates the fast idle valves when the bike is warm,

On a Gen 1 it's easy to view from the LHS of the bike.

Use a screwdriver in and try to move the plate that links the 4 fast idle valves ?
Just push it across to the RHS when the bike is warm and hopefully the revs decrease back to "normal".

RadioHowie's post

 

[bwv]

Have you adjusted throttle cable free play recently? it could be too tight

I adjusted mine too tight and raised the idle... not to 1500.. but it wouldnt go below maybe 1200 no matter how much i backed off the idle screw.

 

[ads245]

Thanks for all the input. I am going to do a TBS to see if that cures the issue and I will also check the fast / cold idle system as well. I checked the throttle cable to see if it was too tight also, but it was okay.

 

[Queensland Ken]

This is my post on the forum trying to help out a Aussie Forum gen 1 owner,.

The fast idle adjustment was screwed all the way, by a previous owner, in order to mask another problem.

There is also a gent on another forum who did the diagnosis ie; to move the plate the activates the fast idle valves when the bike is warm.

His valves are not re-seating back into the throttle bodies when warm and hasn't yet came back to say what he has found.

One thing to note is that eventually, up to 3 bars on the temp gauge 10 minutes riding or so, on both of these bikes the idle eventually came / comes good.

Have you had any work done on the bike recently ??