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Throttle body sync

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PAS

2003 R1150RT

What is the preferred RPM's to synch the throttle body cable? I have the idle perfectly and then at 1850 it's good but when I go to 3000 its goes way off. The cable adjustment is a pain and very sensitive when tightening the lock nut down. Bike is at operating temp also.

Using the harmonizer. New o-ring's on the BBS!

Edited by PAS

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dirtrider
2003 R1150RT

What is the preferred RPM's to synch the throttle body cable? I have the idle perfectly and then at 1850 it's good but when I go to 3000 its goes way off. The cable adjustment is a pain and very sensitive when tightening the lock nut down. Bike is at operating temp also.

Using the harmonizer. New o-ring's on the BBS!

 

Morning PAS

 

If it is good at idle & good at 1850 then it should be close at 3000 rpm's. (maybe not perfect but close)

 

Are your cables tracking clean in the TB cam grooves, are your throttle shaft bushings in good shape (no excessive play?)

 

Very important: do both side TB cams lift of the idle stops at the EXACT same time?, do both side TB cams hit the wide open throttle stops at the EXACT same time?

 

Have you hooked both inputs of your harmonizer to one side TB nipple with a Tee to verify that the harmonizer is accurate & working correctly?

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roger 04 rt

Here's what BMW says:

 

Check and Adjust Left/Right Synchronization at Off-Idle Throttle Positions

- Repeatedly open the throttle gradually and increase engine speed from idle to approximately 2,500 rpm to check throttle-valve synchronization. (Readings shown by synchronization tool must increase and decrease together). If necessary, correct by turning the adjusting screws of the throttle-valve cables at the throttle body.

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rxcrider
...Very important: do both side TB cams lift of the idle stops at the EXACT same time?, do both side TB cams hit the wide open throttle stops at the EXACT same time?

 

If they lift off the stops at the same time but don't hit WOT together, AND there is nothing in or damage to the cable tracks on the the throttle shaft pulleys, it is possible to have a frayed cable on one side of the distributor box. If you need another Harmonizer for comparison, I have one in N Ridgeville and a R1100RT to sync this weekend.

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Unhofliche_Gesundheit

Hello all,

This seems like a good thread to use as a platform for my question:

I am wondering, how "linear" should the TB synchronization be over the RPM range (1100 - 6000),

i.e how close should the balance be maintained over full throttle range

i.e should balance be maintained up thru the whole range as RPM increases? What is the allowable / normal tolerance?

 

On an imaginary scale of zero to five, with five being totally linear, my bike is about a two or three.

Do I need to strive for a four or five, or is non-linear the norm?

 

My problem: I found, in attempting to balance the TBs [2001 R1150 RT. 146000 KM , single spark] the balance could not be made to match at all RPMs - best I could do, basically just matched it at idle (1100) and around 3750 (or thereabouts).

So now, for example it is balanced at idle as stated, but when one opens the throttle to say 1750 rpm, the RH vacuum is stronger than the left, continue to open throttle some more and now the balance changes such that LH vacuum would pull ahead.( i.e non-linear ).

Open the throttle some more again and at a certain point vacuums again match/balance, continue to open and balance is again off, etc.

 

I am using a home made manometer with transmission fluid in it, The amount of "out of balance" might get to be up to or around 6" delta of height of hydraulic fluid between each side.

 

Prior to the balance,

valves were adjusted ( just tight enough to hold all four feelers simultaneously horizonal, a smidge less an would dip from the horizonal)

new bosch dual electrode plugs gapped and installed,

new air filter installed,

idle screws removed & cleaned.

balanced at idle with the BBS idle screw .

both throttle cables set to be just loose enough so they were not holding open the butterflies.

checked for leaks around TBs by fogging outside of each with engine running

 

 

bike seems to now run great (compared to how it was prior to the service, don't have another RT to compare it against) with the current 'balanced at 1100 and 3750' balance

Indeed 3250 - 4000 is where I spend most of my time - so out of balance at 2000 and 5000,( or 7500!) is not really a big issue. I can break the speed limit just fine at 4000, hehe :bike:

However if TBs are intended to be balanced over full range I have an issue to figure out.

On the other hand if TBs typically don't balance over full RPM range then I can sleep well at night and not worry about this.

 

Thanks!

 

 

 

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Jim Moore

You're trying to get the throttle body butterflies to open at the same time. The best place to see a difference in openings is just off idle, 1500-2000 rpm. If they're balance there they should remain balanced all the way up.

 

 

Also, realize you built a VERY sensitive tool there. ATF is lighter than water, which is 13 times lighter than mercury. So six inches of ATF in the tube is less than half an inch of mercury.

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dirtrider
Hello all,

This seems like a good thread to use as a platform for my question:

I am wondering, how "linear" should the TB synchronization be over the RPM range (1100 - 6000),

i.e how close should the balance be maintained over full throttle range

i.e should balance be maintained up thru the whole range as RPM increases? What is the allowable / normal tolerance?

 

On an imaginary scale of zero to five, with five being totally linear, my bike is about a two or three.

Do I need to strive for a four or five, or is non-linear the norm?

 

My problem: I found, in attempting to balance the TBs [2001 R1150 RT. 146000 KM , single spark] the balance could not be made to match at all RPMs - best I could do, basically just matched it at idle (1100) and around 3750 (or thereabouts).

So now, for example it is balanced at idle as stated, but when one opens the throttle to say 1750 rpm, the RH vacuum is stronger than the left, continue to open throttle some more and now the balance changes such that LH vacuum would pull ahead.( i.e non-linear ).

Open the throttle some more again and at a certain point vacuums again match/balance, continue to open and balance is again off, etc.

 

I am using a home made manometer with transmission fluid in it, The amount of "out of balance" might get to be up to or around 6" delta of height of hydraulic fluid between each side.

 

Prior to the balance,

valves were adjusted ( just tight enough to hold all four feelers simultaneously horizonal, a smidge less an would dip from the horizonal)

new bosch dual electrode plugs gapped and installed,

new air filter installed,

idle screws removed & cleaned.

balanced at idle with the BBS idle screw .

both throttle cables set to be just loose enough so they were not holding open the butterflies.

checked for leaks around TBs by fogging outside of each with engine running

 

 

bike seems to now run great (compared to how it was prior to the service, don't have another RT to compare it against) with the current 'balanced at 1100 and 3750' balance

Indeed 3250 - 4000 is where I spend most of my time - so out of balance at 2000 and 5000,( or 7500!) is not really a big issue. I can break the speed limit just fine at 4000, hehe :bike:

However if TBs are intended to be balanced over full range I have an issue to figure out.

On the other hand if TBs typically don't balance over full RPM range then I can sleep well at night and not worry about this.

 

Thanks!

 

 

 

Morning Unhofliche_Gesundheit

 

You want it perfect all the way from idle to max RPM-- BUT!, you will NEVER ever see that.

 

Even the curb idle balance (basic hot engine idle) is not that important to get exact as you never ride it at that throttle setting.

 

The balance (air flow through the throttle plates) should be as close as you as you can manage to get in the most used operating range at the surging RPM. (3000-4000 RPM range).

 

Keep in mind that you are basically setting the cross side balance at NO engine LOAD but you ride the bike at road load so whatever you set statically at no-load (free revving) is just a way to do a basic balance. (basically at road load the throttle plates will be more open for the same RPM than they are at static free revving no-load)

 

The important things are the cross side fueling as the FUEL balance to each side is more important than a slight air flow difference. (problem is, there is no good way to measure or correct that). Making the fueling richer (aftermarket fuel controller) is the best approach as a slightly richer fuel/air mixture is MUCH more forgiving as far as smooth engine operation & surging reduction goes.

 

The next important thing is to be sure that both side throttle cams lift off the idle stop screws at the EXACT same time & hit the wide open stops at the exact same time.

 

Bottom line: get the cross side balance as close as you can in the 3000-4000 RPM range & be sure that both side throttle cams lift off the idle stop screws at the EXACT same time & hit the wide open stops at the exact same time.

 

 

 

 

 

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tallman

Most of the time under 4,000?

:S

Best of times are above 4,000.

:Cool:

Best wishes/

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PAS

Interesting to see my old post revisited. My 03 1150RT rode off into the sunset this past summer with a new owner. I still enjoy viewing this site on occasion. I'm back to enjoying the simplicity of my 81 R100RT!

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Michaelr11
Hello all,

This seems like a good thread to use as a platform for my question:

I am wondering, how "linear" should the TB synchronization be over the RPM range (1100 - 6000),

.................

Prior to the balance,

valves were adjusted ( just tight enough to hold all four feelers simultaneously horizonal, a smidge less an would dip from the horizonal)

new bosch dual electrode plugs gapped and installed,

new air filter installed,

idle screws removed & cleaned.

balanced at idle with the BBS idle screw .

both throttle cables set to be just loose enough so they were not holding open the butterflies.

checked for leaks around TBs by fogging outside of each with engine running

..........................

On the other hand if TBs typically don't balance over full RPM range then I can sleep well at night and not worry about this.

 

 

As DR says - you'll never get it completely linear, so sleep well.

At the mileage (140+ km) of your bike, I'm a little surprised that your throttle bodies don't have air leakage around the TB shaft and bushing. Consider the TB rebuild kit which will give you a new TB shaft, bushing and o-rings.

 

I would pull the injectors out and have them cleaned by an injector cleaning service. They will give you a report of flow rates before and after cleaning. This will give you more equal fuel delivery at all RPM.

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tallman
Interesting to see my old post revisited. My 03 1150RT rode off into the sunset this past summer with a new owner. I still enjoy viewing this site on occasion. I'm back to enjoying the simplicity of my 81 R100RT!

 

Speedo broke at 189,000+ on my '80 R100 RT.

Rode it for another 20 years.

Simple by Choice.

Best wishes.

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Unhofliche_Gesundheit

Thanks. This is good and helpful. (especially this " You want it perfect all the way from idle to max RPM-- BUT!, you will NEVER ever see that. " ) So my main take away :

next time (after setting the idle with both TB cables loosened),

-endeavor to get both throttles to open at exactly the same time (easily verified with the manometer movement),

-Then move on to maybe tweaking the balanced at my favored riding RPM.

I don't think will be able to do much about ensuring they hit the full open stop at the same time.

 

For now aftermarket fuel controller is not in the cards, my contract ended and now have no income coming in.

I used to say, your three personal resources are 'time', 'money', and 'motivation/ability/skill'; and further that for some reason one of the three is always lacking at any given time, i.e. so now I have time and motivation but not money.

(And actually as I get older, I am pretty happy if I can manage to have two out of three - as it is very possible to have only one, or NONE ! )

 

I always add injector cleaner to the fuel tank on every oil change, so hoping that is doing its job and avoid the cost of paying someone to look at them. Bike is running great, pulls strong. Too bad its snowing here.

I am planning for new SS brake lines. Any in a perfect world would upgrade from my Calsci windscreen and locally reupholstered seat, but living with them. Even with no main day job it is still hard to get much riding done with young kids.

 

All the best.

 

 

 

 

 

Edited by Unhofliche_Gesundheit

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