The blue paint flakes off on a lot of bikes so i wouldn't use that as a sign they've been tampered with.
Throttle body balancing... need advise as someone has been messing !
- Thread starter beaver
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The blue paint flakes off on a lot of bikes so i wouldn't use that as a sign they've been tampered with.
Agreed, but differances at tickover on the vac gauges, screw heads with burrs on them, the paint that is left on the screw not matching the body ... all says to me 'messed with'
At least with a virgin pair " ooo er Mrs" I have a datum.. and for £100 its not worth messing and going around in circles... also they have only 10K on them so seals etc should be better?.. will see when they arrive
FWIW there are no volts settings needed for throttle potentiometer calibration, the ecu learns 0-100% and a GS911 can be used to check TPS output.
A simple TPS reset procedure takes 2 minutes, during which the ecu relearns the settings.
A simple TPS reset procedure takes 2 minutes, during which the ecu relearns the settings.
Okay.. thanks for the info... Id still need to set the units to a given gap / flow.. and I don't have a 911 so for me this was the way to go.....
I do know someone with a 911 and will have a go with it at some point in the future...
Hate having issues with things so if it get it up and running fine its money well spent... Thanks for all your help anyways...
Bendy toy
Registered user
The steppers self park when engine is turned off. They set their tick over point when the engine is switched on. That point is learned from the TPS. The TPS is connected to only the LH side so the RH is simply mimicking what the left does.
The LHS one is the datum. I'll set the right to this via the cables and balancing. But it's the factory setting I can't get hold of.... Will measure the new ones when they come and post here... I'll reset mine and can sell on
There's the cause of your rough running!
Bendy toy
Registered user
There's the cause of your rough running!
That would do it.
We should have suggested the Easy Start test. Spray it where you suspect an inlet air leak. If the revs change you have a leak that needs checking out.
Pale Rider
Registered user
I know this is now an old thread, but why is it important to disconnect or park the stepper motors before carrying out throttle balance? Why can’t you just fit the gauges and do it with them connected?? Sorry relatively new to GS mechanics.
The ecu is constantly moving the idle air bypass stepper motors to regulate a steady idle. It is bypassing air around the throttle butterfly and fighting against any adjustment you make.
By parking the idle steppers to lock them out, you can then accurately balance throttle butterflies manually.
Pale Rider
Registered user
Brilliant I’ll give it a try, must admit I have set them up with the stepper motors connected as I didn’t know any better.
So did I.
They were out, I balanced them and it felt better after… I rev’d it to about 3-4k and balanced them at that point.
Now I know better, I’ll do them again.
When you have disabled the steppers as per the great info above, do you still need to balance them at 3-4k or can you then balance them lower?
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I use a GS911 to lock mine out of the way, then balance idle first. Once happy I then rev to 4K for a brief moment and fine tune, test again and again until smooth. GS911 unlock the steppers before stopping the engine.
Obviously all other service work should be done first like cold valve clearances, then engine brought up to running temperature before doing the throttle body synchronisation.
Obviously all other service work should be done first like cold valve clearances, then engine brought up to running temperature before doing the throttle body synchronisation.
you ride the bike at low speed mostly with the throttle open and manoeuvrer in traffic opening and closing the throttle seldom hitting idle
thus you want the balance correct at the point where it matters - as the butterflies are just opening via the cables - idle balance is pretty much a waste of space - you also need enough air flow that you can make a sensible judgement - so always do on a warm engine around 3 to 4k (always held open via the throttle grip)
thus you want the balance correct at the point where it matters - as the butterflies are just opening via the cables - idle balance is pretty much a waste of space - you also need enough air flow that you can make a sensible judgement - so always do on a warm engine around 3 to 4k (always held open via the throttle grip)
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This.
The balance adjustment is only made with the cables.
It’s the take up from idle that you are trying to match,this is the point that a stutter or imbalance will cause the biggest issue.
You need a smooth progressive take up,particularly with a big twin.
On a 1200, stepper motors either disconnected or locked.
The balance should be adjusted at the very point the cable opens the butterfly.
Assuming vacuum gauges are used,the 1st butterfly that opens will cause a slight dip in manifold pressure,(vacuum)
Let’s say the l/s dips first,
Check the free play in the cables,if they both have a little(say1 to 2mm)
The rh side could be tightened up so both the gauges move together
If the free play is a little tight,the l/h could be loosened till the gauges move together .
Have a play,take one of the adjusters out 1/2 turn you can always put it back.
TB balance should take no more than a few mins.
One thing I have noticed though over the years,
Some of the twin cams throw a wobble after locking the TB bodies,
If you experience a surging idle after balancing you need to do an adaptation reset.
A gs911 really is a bit essential to home service on a 1200.
It does a lot more than reset the service reminder.
Pale Rider
Registered user
So regarding getting a gs911 tool what do i need? One of those triangular orange ones off of Amazon for £108 or the more oblong green and black one for around £300?
I was an 'early adopter' and bought my GS911 a long time ago, opting for the bluetooth and USB version. It has (and still does) served me well, I use it at every service and have helped a few other folk with it.
If I was considering buying a newer BMW bike with LINBUS and CANBUS then I would buy the newer red/black coloured WiFi enabled GS911, but I intend keeping my old Hexhead GSA for a few years so the yellow GS911 I have works just fine.
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