Idle rising when bike gets hot?

speirmoor

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Cruising around today and after about an hour idle would settle at around 2K RPM at stoplights. Then randomly on some stops it would rise to 3K RPM and settle back down to 2K RPM again. I could get the revs down again by riding the clutch but ideally I shouldn't need to do that. When I got home I checked for loose cables, set screws, adjusters etc but nothing seemed out of place It was fine when the journey began I'm wondering whats happened in the meantime?
 
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Sorry did not initially notice NORTON MODERN please disregard
 
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iwilson

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Could be a problem with the idle air control. The design of the system is flawed and can allow the ECU to become confused and unable to control the idle speed. I investigated this at length and ended up removing the entire system! Not guaranteeing it is your problem, but I experienced the exact same problems on and off and since removing the IAC system the bike has never exhibited those symptoms again and in fact has never run better!

Idle problem solved
 

BritTwit

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Simplest thing to check is the tightness of the 2 screws holding the IAM to the throttle body.
If loose, the effect is a wild (up and down) idle.
 

MAK

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Cruising around today and after about an hour idle would settle at around 2K RPM at stoplights. Then randomly on some stops it would rise to 3K RPM and settle back down to 2K RPM again. I could get the revs down again by riding the clutch but ideally I shouldn't need to do that. When I got home I checked for loose cables, set screws, adjusters etc but nothing seemed out of place It was fine when the journey began I'm wondering whats happened in the meantime?
Cruising around today and after about an hour idle would settle at around 2K RPM at stoplights. Then randomly on some stops it would rise to 3K RPM and settle back down to 2K RPM again. I could get the revs down again by riding the clutch but ideally I shouldn't need to do that. When I got home I checked for loose cables, set screws, adjusters etc but nothing seemed out of place It was fine when the journey began I'm wondering whats happened in the meantime?
 

MAK

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This is exactly what happened to my bike..
2016 MK2.Omex
Renewed idle control valve and checked everything.
After advice from this marvellous site I removed Lamda sensors,blanked holes then bridged out connections with an Aprillia part.
All off e bay.
Bike now performs correctly with an even tickover .
That’s where I would start or you could end up chasing your tail.
 
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Thanks all. I ordered the plugs so lets see what happens.
You don't have to remove the O2 sensors from the pipes for now. Just follow the wires up under the tank , unplug O2's and plug the eliminators in their place. Look at the threads or find Richard-7 manuals on Domi Exhaust. For now , don't touch the Throttle stop screw .
 

BLIGHTYBRIT/SF

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You don't have to remove the O2 sensors from the pipes for now. Just follow the wires up under the tank , unplug O2's and plug the eliminators in their place. Look at the threads or find Richard-7 manuals on Domi Exhaust. For now , don't touch the Throttle stop screw .
Exactly what I done couple years ago , all running like a well oiled machine
 
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Thanks all. I ordered the plugs so lets see what happens.
I have the plugs. There is an improvement. That said, on three seperate occassions, the flange screws backed out ever so slightly creating a small gap. That was enough air to get sucked in and make my idle raise to 2400. After I tightened them, the problem ceased. I've ridden all winter without the idle racing. Went out in 70 F and its raising to 2K. Havent checked the flange screws yet and that soft poly flange isn't going to hold up forever. Try it. Might work. 2MM allen wrench.
 

speirmoor

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Thank you, the picture helps. I was in the right vicinity but at the wrong thing altogether. I was attempting the ones l had circled
2v2HtoCvWxAn6Wm.jpg
 
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John, as pictured, only tightened the 2MM screws on the flange. There was a slight gap on the face of the diamond shaped flange. Happened a few times because the bend in that hose puts an odd leverage on the flange. Unfortunately, that soft plastic isn't going to hold up. Thinking on making a paper gasket. Thanks for the diagrams, Fred.
 
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