Wandering Tick over

[fatnfast]

Help please..
At tickover the revs on my 02 GS wander slightly up and down. You can see this in the rev counter needle and hear it in the engine note. I have checked the valves per the american oil head guide and also the balance using a twinmax. Both show everything to be in order.
It is only slight and iregular, but why is it doing this?

 

[cookie]

air leak?

 

[fatnfast]

wish it was an air leak, all screws are tight, nothings perished, cant hear any air being sucked in or out....

 

[Spout]

I'm not sure if any of the fuel injection system sensors operate at tickover, but it could be the "cycling" they go through adjusting fuel/air mix. Shouldn't do it of course, so somethings wrong.
Similar to the surging that can happen at low throttle openings.

 

[turbine_2]

When this happened to mine it was reported initally to be the lambda sensor and then the motronic unit.

 

[fatnfast]

so what eventually solved the problem David, was it the motronic unit? Its not a huge 'swing', the tickover wanders just below and above the 1000rpm marker. I have tried increasing the tickover (including rechecking the balance), but it does the same thing, just higher up (relativly speaking) the rev band. It does not effect the performance further up the rev range and will idle without stalling, so I could live with it. But if its not supposed to do this........

 

[Mouse]

For what it's worth, the tickover has never been totally steady on my 10 month old computer controlled stepper motor equipped R1200GS. It only wanders by maybe 100rpm though.

 

[skywalker]

throttle body manifolds -paticularly the left one.with the engine ticking over ,spray the manifold with wd40 or similar and watch the tickover change.replace the manifold as sealing it with slicon doesn't work.Do loads of them.

 

[fatnfast]

Thanks for that skywalker, sprayed as suggested but did not see any difference. Did notice that there is a small allen screw to the rear and underneath the L/H throttle body. There is a tiny mist/fluid leakage from here. The screw is tight. Could the washer on this cause the problem and what is the 'fluid'? I assume its fuel. Also, the brass air screws. I did take these out and clean them as part of the checks. They were covered in a white grease. I take it they must be regreased, but what grease and do I apply this just to the threaded portion (the whole of the air screw was covered in the stuff)? Thanks again for all your help so far....

 

[skywalker]

Thanks for that skywalker, sprayed as suggested but did not see any difference. Did notice that there is a small allen screw to the rear and underneath the L/H throttle body. There is a tiny mist/fluid leakage from here. The screw is tight. Could the washer on this cause the problem and what is the 'fluid'? I assume its fuel. Also, the brass air screws. I did take these out and clean them as part of the checks. They were covered in a white grease. I take it they must be regreased, but what grease and do I apply this just to the threaded portion (the whole of the air screw was covered in the stuff)? Thanks again for all your help so far....

The bolt should have an earth strap running off it(anti statis strap). The oiley mist is more than likely a combination of fuel & oil vapour since the engine breather vents into the airbox.
re the brass screws - i use coppa slip on the threaded portion, it saves alot of aggro later.we do this on all our bikes.Trying to get a seized bleed screw out is no fun.
If your bike is a twin spark gs with a lamda sensor fitted it maybe worth getting it tested.If you've got an 1100 it maybe worth getting the co value checked - factory setting is 1.5% but we set ours up to 2 to 2.5 %

 

[skywalker]

Oops sorry just read that its an 02

 

[fatnfast]

Thanks again, will use coppa slip on the air screws. Yes the allen screw has an earth strap on it. As it has this oily mist (yep, it is like petrol/oil mix) could this then be the leak? Mines the single spark 1150. Did have the Lamda sensor changed a while back under warranty as the bike would cut out after long runs for no reason (still cuts out once every 1000miles or so) Prehaps the next step is to let the dealer have a look and adjust the co as you suggest. Weird this, I know it never used to do it. Perhaps I am just crap with the Twinmax!

 

[skywalker]

If you have a lamda sensor fitted then you won't be able to adjust the co.This sensor goes part way to controling the fueling. The leak at the bolt won't affect the mixture as its on the airbox side.something else to get checked is the throttle sensor setting and also make sure that the throttle bodies aren't hanging on the cables

 

[fatnfast]

Hmmm, time to let the dealer have a peak then. The bike does have a y-piece and remus revolution, no baffle, but is otherwise standard.It has alaways had these fitted. It is only a slight movement but I just hate things not being just so. Thanks for all your help Skywalker, at least I can show some knowledge when I book it in (and I am an electrical engineer by trade, so I am anoyed I can't put my finger on the fault!).
Will report back with their findings....