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Discussion Starter · #1 ·
What do the air box sensor and the engine temp sensor do. Which one is responsible for adjusting the choke on the throttle bodies. Ie Air valve controll.
 

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Wrencher Extraordinaire
2005 K1200LT
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14,561 Posts
The air valve is not a choke but rather sets the idle speed. The air box sensor modifies the pulse width on the injectors based on air temp. Disconnecting this will help with hot temperature stumbling if you experience this as it leans out the mixture. There was also a "brown wire cut" mod for the early bikes that would force an alternate fuel map to do the same thing. Never do both as that will lean out the mixture too far and you will risk detonation damage.

The engine temp sensor on the back side of the cylinder head controls the trigger point for the cooling fans (quick way to test the fans is to disconnect this sensor to force the fans to "ON") and modifies the pulse width for the injectors for mixture control based on engine temp.
 

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Discussion Starter · #3 ·
What operates the Throttle actuator? ive replace all the electrics on the throttle body but it remains in an open position giving a start up revs or 1700rpm and stays there all the time never dropping to 900rpm
 

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Wrencher Extraordinaire
2005 K1200LT
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14,561 Posts
Is your TPS set correctly? Are all the springs on each of the butterflies?

I had one bike that ran like crap and goofy high idle, GS-911 said TPS was out of range and we never touched it. We did have the entire assembly off the bike for cleaning and accidentally removed one of the springs. Put the spring back on and she purred like a kitten. This meant on "key on" the throttle bodies were not fully closed and the TPS read this as an out of range indication.

Also if that bracket that the Throttle Actuator is on gets bent that can throw off the idle. Do you have a GS-911, if so does it indicate it is set correctly? If you are trying to fix this with out one you will never get there.
 
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