High idel RPM, rough ride when riding slow - K-Bikes.com - Excellence in Motion
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post #1 of 5 (permalink) Old Nov 12th, 2018, 2:06 pm Thread Starter
Join Date: Nov 2018
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Unhappy High idel RPM, rough ride when riding slow

Hi all,

I have a 2008 K1200s, 38000km. Serviced every 10,000km, The last service at 30,000km I had the plugs changed and valve clearance checked etc.

On my work commute I spend about 20 min on the road doing ~120kmph (75mph), after 20min and I slow down at an intersection and ride slowly through traffic. When riding with little or no throttle the revs will be much higher than usual, when running normal the idle is at about 1000RPM, but when this issue occurs the idle goes up to as high as 2500PRM. This cause the bike to not engine break effectively and to speed up. It makes slow riding almost impossible without riding the clutch. It doesn't stay consistent at 2500RPM either, it will suddenly drop back to 1000RPM causing the bike to engine break throwing me forward, after I turn on the throttle to drive on it returns to high revs.

The strange thing is that if I give it some power, say bring it up to 4000RPM, I wouldn't have issues and it appears to run ok unless I try to slow down. Added to that if I turn off the ignition, while driving and just coast for 2 seconds, and turn it back on again the problem goes away for another 20min or so. I can slow ride and bike runs as normal. It also doesn't happen when the bike is cold. It only seems to happen if I have been riding at constant high speed for about 15min and then slow down. It doesn't happen if I am constantly slowing down and stopping at junctions or in city driving.

I had the TPS changed and the plugs have been replaced with new plugs and was fully serviced about a month ago. The mechanic hasn't been able to find the problem and there are no error codes coming up.

Any advice or info will be appreciated as I cant really ride it as its too dangerous to be in heavy traffic and it is unpredictable.


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post #2 of 5 (permalink) Old Nov 13th, 2018, 12:51 pm
Join Date: Aug 2018
Posts: 20
Same here

I have a 2008 K2000GT that has the same problem and I put up with it until the weekend when I got stuck in bumper to bumper traffic down shifted and let off the throttle, but the bike stayed at 3K. That was not fun. From what my research has found is that there were 3 different air boxes until part of the problem was solved. There is also a controller that can get clogged and has to be cleaned or replaced. Not sure which air box I have so my dealer is checking to see what is causing the problem. Mine has 36K
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post #3 of 5 (permalink) Old Nov 17th, 2018, 1:32 am
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Location: Seattle, WA, USA
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I'm on an '08 K 1200 S myself. I think what you are showing is Idle Control problems. I know less about the electronics then the mechanics but there are 2 sensors on the back/middle of the Airbox under the Gas Tank. They are the Idle Control Sensors and are operated by vacuum levels entering the sensors via vacuum tubing coming from the Engine Top and Bottom-Ends . But if they malfunction it should throw codes. There is the condition of your vacuum hoes and clamps to consider. You might also check to be sure your Charcoal Canister isn't plugged. I recall older LTs had difficulty with that. The exit hoses from your sensors goes right out the Canister. I took my Canister off.

I actually haven't run a Stock Injector Tune for 5 years. I built my own exhaust, added K&N Filters and a few other things so had to go to a Power Commander. Got a pretty close tune on that and haven't had any Idle Control issues out of it accept at High Altitudes (above 6000 ft.). That indicates a Rich Condition which, from your description, sounds the same (High Idle usually = Rich).

You might ask the Beemer guy if the Idle Control Sensors do, in fact show a code when they fail. I also wouldn't doubt there is a ReZap of your ECM in your future.
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post #4 of 5 (permalink) Old Apr 15th, 2019, 10:02 am Thread Starter
Join Date: Nov 2018
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I forgot that I had posted this here a few months the ago. I had left the bike for the winter and just didn't use it. I took apart the idle control sensor and cleaned it out. I also gave it a run with some sandpaper just to make sure it's wasn't sticking in the air box. I also used half a bottle of fuel injector cleaner additive. It seems to have fixed the problem and hopefully it won't be anything else. Thanks for the advice
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post #5 of 5 (permalink) Old May 27th, 2019, 12:15 pm
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There is another thread about this somewhere. But, most likely it is the idle air valve (13 71 8 523 475 IDLE SYSTEM) that is jammed up. The air box warps in warm weather or when the bike gets hot, this contributes. There is an up dated air box if your bike does not have it already. Along with some computer software updates that happened in October 09. You can take this valve apart and clean it or buy a new one. GT models behave even worse for some reason. As mentioned idle problems can also be caused by a flooded carbon canister or the over flow vent plugged by some creature. Most remove the system.

Mount Vernon, WA.
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high rpm, idel, k1200s, rough, slow riding

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