Idle Control Valves

[Greyscout]

Ever wondered what goes on inside the idle control valve ....... read on ! Before you panic - this was one was U/S which is why it was dissected ! Rather disappointing because on the outside they looked really clean - but more on that later.







Starting from the right we have a permanent magnet with an internal threaded insert. The next item to the left has two coils or field windings, one to make the magnet spin one way, the other reverses the magnet. You will see that the plunger on the far left is also threaded, so when the magnet spins, it causes the plunger to move into or out of the spinning magnet.



There is a small bearing at the top of the magnet, this one was seized due to water ingress, which explains why the idle valve wasn't working !



Here you can see the two coils which create the field to make the magnet rotate.



In this picture you can just make out the 4 very fine wires (two for each coil) which would connect to the plug on top of the idle controller.

 

[Kiwi66]

Thank you for taking the time to post this.
I am about to replace mine as part of a strategy to isolate the bikes stalling (F800gs). Would be interesting to see if the conditions of the controller are the same as yours.

 

[Mistacat]

Just out of interest did the failed idle actuator show up on the diagnostics ?
As far as I can see both actuators mirror each other and do not have a feedback circuit so the ecu does not now where they are, just where they should be.
Hence the need to reset the base positions.
Would have been nice if they were designed as individual circuits with feedback and controlled by MAP sensors.
Nice to see the pictures of a dismantled unit and that they are not moisture proof.

 

[BlueBird]

now this is a worthwhile post, particularly for those of us with higher mileage.

Thanks

 

[Greyscout]

Just out of interest did the failed idle actuator show up on the diagnostics ?
As far as I can see both actuators mirror each other and do not have a feedback circuit so the ecu does not now where they are, just where they should be.
Hence the need to reset the base positions.
Would have been nice if they were designed as individual circuits with feedback and controlled by MAP sensors.
Nice to see the pictures of a dismantled unit and that they are not moisture proof.

They came on a pair of TBs that I picked up at an autojumble, they appeared to be in really good condition with very little use, but when I fitted the TBs to my 05RT it refused to tick over and would only run if quarter throttle was applied. It was at that point I realised I hadn't heard the idle controls valves do their test n reset routine, so I swapped them for my tatty looking ones and bike ran a treat. (Both were seized but they were seized in different positions, one was fully extended, which would have starved the TB of enough air to run at tick over).

What is interesting is the plastic top where you connect the harness has an O ring fitted where it clamps into the metal body of the idle controller and it is crimped in place. So in theory water ingress should be limited - but maybe if high pressure jet washes are used on a regular basis (you boys who like to get your GS dirty) this might be an issue ? The only other possible route for moisture ingress is up past the shaft as there is no seal fitted that end. Could it be condensation forming - hot cylinder head underneath a relatively cool TB ?

 

[Bendy toy]

Maybe lack of use does the damage but it looks like time to replace my 9 years old 65,000 miles idle stepper motors. I've got a lumpy tickover (unaffected by throttle balance or valve clearances) though no other issues.

 

[Mac One]

Every day's a school day. Thanks.

 

[Greyscout]

OK I know this isn't the RT section, but I roadtested the bike today with the GS throttle bodies fitted. It was semi naked so not really an RT at the time

Bike seems to run better with the GS throttle bodies fitted so I am chuffed !

 

[Bendy toy]

The smaller throttles should improve fuelling at the lower end of the scale.


Sent somehow.

 

[Steptoe]

Maybe the damage happened while being left out in the open and stored damp/wet for weeks while being carried from auto jumble to auto jumble Lot of auto jumbles are out in the open, if it rains the storage boxes get filled with water and then chucked in the van and left until the next jumble

 

[BlueBird]

on the strength of this I opened up one of my 100k steppers It was in great nick inside and its been through some rough shit, Thing is if you open them up watch for the 3 pins, knocking them in to far can spilt the housing inside and the wires to the coils, theses are short and its clearly not supposed to be opened up.

 

[Greyscout]

on the strength of this I opened up one of my 100k steppers It was in great nick inside and its been through some rough shit, Thing is if you open them up watch for the 3 pins, knocking them in to far can spilt the housing inside and the wires to the coils, theses are short and its clearly not supposed to be opened up.

Bluebird - sorry yes I should have mentioned the pins need to come out rather than go in. Which is almost impossible as they have chamfered edges so nothing to grip. Only alternative is to open up the metal sides (they are very soft and they split very easily though). So getting it all to seal up suitably again later will be challenging....

Like you say, I don't think they're designed for "repair" - and by the sound of it I was just unlucky with mine being in such a state. Be interesting to see if anyone else has had one fail though ?

 

[Greyscout]

The smaller throttles should improve fuelling at the lower end of the scale.


Sent somehow.

Bendy - the throttle bodies are identical in size at least on the single cam models between 05 and 08 anyway.

 

[Bendy toy]

Fair enough.

By the way I suspect the intake tube causes a huge restriction. Cutting 6" off the end & flaring the tube would no doubt reduce intake resistance. Who know how that might translate in real world terms.


Sent somehow.