Throttle Synchronization

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Throttle Synchronization

Post by Our Gee »

Now that I have entered a regime of doing as much maintenance on my Twincam as I can myself (fed up with poor dealer service) I was wondering just how frequently the Throttle Synchronization actually requires "adjustment". The BMW maintenance schedule does stipulate a check every 6000 miles but after my last two dealer services the Technician, when quizzed, said everything was fine (that included the valve clearances). Does anyone have experience of this. Thanks.
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David.
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Re: Throttle Synchronization

Post by David. »

On my 2012 TC, the throttle synchronisation was first done at 10,000 miles. I'd have to say that, the bike felt crisper to respond afterwards.

It was next done at 15,500 miles, the idle speed was hunting a little, now seems smother.
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Re: Throttle Synchronization

Post by simbo »

Hi, Has anyone any definitive information on balancing the throttle bodies on a 1200TC? I've read various different threads on forums and there's a lot of conflicting opinions regarding the matter. I've balanced mine today and the bike feels crisper and less vibey with more of an eagerness to rev up quicker  :)  I didn't park/disconnect the stepper motors as from what I've read they only control the sync at idle by gathering information from the ecu and o2 sensors and the sync once above idle is controlled by the cable operation, The idle was fine and in sync (before & after) my adjustments, but once the bikes revs were raised above idle the left cylinder was pulling more air (about 1lb) and rising as the revs got higher, I adjusted the right throttle valve via the cable adjuster on the TB to bring them in line with each other, they were only small adjustments but made quite a difference.
[size=2px]Any other info or experiences welcome 👍
[/size]
The GS 'is' the better bike :-)
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Re: Throttle Synchronization

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simbo
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Re: Throttle Synchronization

Post by simbo »

Thanks, it was an interesting read 👍 pretty straightforward job after all.
The GS 'is' the better bike :-)
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Re: Throttle Synchronization

Post by David. »

Just been to The Workshop at York, http://www.theworkshopyork.com/ to have what BMW describe as "Correcting engine synchronisation (for maintenance).

Paul was very helpful, he was happy to let me observe & discuss the work being done. Vacuum gauges were used to check that as the throttle is opened, the adjustment of the cables is correct & the throttle butterflies are working in synchronisation with each other, all was ok, with no adjustment necessary. The next check/adjustment was "black magic" to me. Using diagnostic equipment plugged into the bike, I believe that the stepper motors are reset/calibrated together with the throttle position sensor.

The best part of it was that Paul charged half of what a BMW dealer would charge for the same job.
Plus the work wasn't carried out behind closed doors with no feedback from the person who worked on the bike.
Last edited by David. on Thu Oct 18, 2018 6:01 pm, edited 1 time in total.
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Re: Throttle Synchronization

Post by David. »

This video seems to complement what is posted above, BMW R1200 / R NineT 2005-Current Throttle Body Sync DIY How to - YouTube
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Re: Throttle Synchronization

Post by sakm »

David. wrote: Just been to The Workshop at York, http://www.theworkshopyork.com/ to have what BMW describe as "Correcting engine synchronisation (for maintenance).

Paul was very helpful, he was happy to let me observe & discuss the work being done. Vacuum gauges were used to check that as the throttle is opened, the adjustment of the cables is correct & the throttle butterflies are working in synchronisation with each other, all was ok, with no adjustment necessary. The next check/adjustment was "black magic" to me. Using diagnostic equipment plugged into the bike, I believe that the stepper motors are reset/calibrated together with the throttle position sensor.

The best part of it was that Paul charged half of what a BMW dealer would charge for the same job.
Plus the work wasn't carried out behind closed doors with no feedback from the person who worked on the bike.

Its at this point that I like to get stuck in well I lie! I like to get stuck in all the time from the smallest to the largest jobs!


A throttle body sync is pretty straight forward to do on most bikes and I am led to believe pretty easy on yours as most stuff is easily accessible
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Re: Throttle Synchronization

Post by David. »

sakm wrote:A throttle body sync is pretty straight forward to do on most bikes and I am led to believe pretty easy on yours.
Even easier on yours (a Wethead),  it doesn't need doing!
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Re: Throttle Synchronization

Post by sakm »

David. wrote: Even easier on yours (a Wethead), it doesn't need doing!

Yeah I know just reset them with a gs-911 if you feel it needs doing


Which makes my new digital 6 cylinder balancer pointless now! only bloody used it once too!
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Re: Throttle Synchronization

Post by David. »

simbo wrote:I didn't park/disconnect the stepper motors as from what I've read they only control the sync at idle by gathering information from the ecu and o2 sensors and the sync once above idle is controlled by the cable operation.
I've been trying to get my head around this and have come to the following conclusions. At idle, the throttle body butterfly is held partially open by the "do not adjust" throttle stop. The stepper motor works a plunger within a bypass airway, like a pilot air screw on a carburettor. With feedback from the O2 and other sensors on the engine, the ECU adjusts the stepper motor to control what I believe are emissions by allowing more or less air through the bypass. When on the throttle at 1400 to 1800 RPM, the cables are adjusted to balance the vacuum on each cylinder. I think that the stepper motors are reset/calibrated because they may stick or get out of sync. Plus, they are "parked" during cable adjustment to ensure any small bypass air doesn't affect the throttle balance.

This photo shows the bypass airway on the throttle body.

Image

These are the specs. for vacuum at idle and on the throttle.

Image

This video shows a throttle body being stripped of its component parts, R 1200 GS Tear Down: Throttle Body Disassembly (a Nicht Uber Max video) - YouTube
Last edited by David. on Mon Jan 03, 2022 1:33 pm, edited 1 time in total.
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Re: Throttle Synchronization

Post by simbo »

David. wrote: I've been trying to get my head around this

For Four years lol

The GS 'is' the better bike :-)
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