More Throttle Body Balancing Dramas

[Pale Rider]

Ok so iv'e fitted the new BMW TPS, reset the adaptations, locked the stepper motors and set the throttle bodies to pretty much what appears to be spot on on the vacuum gauges, although i did wonder where abouts the murcury needs to be in the glass, mine is showing roughly a third of the way up the glass tubes, should it be nearer the top? All set up using my GS911 as instructed but it just doesn't seem right, the revs just don't seem to settle down as they should and strangely if i very slightly pull on the left hand cable the revs rise as one would expect but if i pull the right hand cable the revs fall?? Also getting the odd stutter now and then. All cables seated properly, Any ideas fellas?? Thanks.

 

[mpgscott]

I was having similar and I checked that coil packs were ok.

As long as at 3000rpm your seeing good agreement between both sides on the gauges then you should be fine. Attached a pic of what I was getting.

Suggestions are to only adjust the right side (one without TPS) when doing the TB balancing, however you need a basline first.

I had mine running fine at 3k then it just wouldn’t idle. So I ended up swapping all 4 coil packs but test first no point changing for nothing. Easy to test just unplug and see bike will run, mine was going on just 1 so easy enough to find a rouge pack.

If I was at home I could of sent you a couple down as I swapped all 4 but 2 were ok.

Here don’t go on me alone, folk with far more knowledge will be along. It was definitely my cause for it not idling.

 

[Pale Rider]

I was having similar and I checked that coil packs were ok.

As long as at 3000rpm your seeing good agreement between both sides on the gauges then you should be fine. Attached a pic of what I was getting.View attachment 520829

Suggestions are to only adjust the right side (one without TPS) when doing the TB balancing, however you need a basline first.

I had mine running fine at 3k then it just wouldn’t idle. So I ended up swapping all 4 coil packs but test first no point changing for nothing. Easy to test just unplug and see bike will run, mine was going on just 1 so easy enough to find a rouge pack.

If I was at home I could of sent you a couple down as I swapped all 4 but 2 were ok.

Here don’t go on me alone, folk with far more knowledge will be along. It was definitely my cause for it not idling.

Thanks for your reply mate, and you may just have solved my problem. I balanced it at tick over and not 3000 revs so that may just be where I’m going wrong. I have set it up using the GS-911 in the past but a little while ago so forgot about the 3000 revs. Thanks fella I’ll re-do it then and report back

 

[waggy]

I was watching The Old Mechanic and he was doing the balance on the Twin Cam and he said you should not park or disconnect the Stepper Motors. And apparently it says this somewhere on the GS911 site/ forum, I will see if I can find it and post it here


Sent from my iPhone using Tapatalk

 

[Pale Rider]

Well. Just been out for a 50 odd mile ride and its never been smoother! the odd stutter seemed to be connected to the raised tick over so adjusted that and its super smooth, seems a lot more responsive and seemingly with a fair bit more power! Popping on the over run all but disappeared and average mpg gone up from 54.3 which its been for a long time to a staggering 60.1!

I will have another play tomorrow with the GS911 and set it at 3000 revs and see if it makes a difference, but like I say I don't think it's ever been better since I've owned it.

BUT this still doesn't explain why the revs drop when I slightly raise the right cable but not the left, or perhaps that's just how it is?

 

[Steptoe]

BUT this still doesn't explain why the revs drop when I slightly raise the right cable but not the left, or perhaps that's just how it is?

Here’s a big clue… the L/H throttle has the TPS attached to it.
The R/H throttle doesn’t.
Now think about it …… what does the TPS do and what does it control ?
It involves controlling the fuel at throttle openings, and only one throttle body is fitted with it…….
These aren’t carburetors which separately/individually suck in fuel and air if a butterfly is opened .

Worked it out yet ?

 

[Pale Rider]

Here’s a big clue… the L/H throttle has the TPS attached to it.
The R/H throttle doesn’t.
Now think about it …… what does the TPS do and what does it control ?
It involves controlling the fuel at throttle openings, and only one throttle body is fitted with it…….
These aren’t carburetors which separately/individually suck in fuel and air if a butterfly is opened .

Worked it out yet ?

What’s with the attitude fella?? Was just asking a question, a very valid question on an Internet forum I thought. Unlike your good self im not a professional BMW tech so have no idea why (that’s why I asked) and in answer to your question, no I’ve not worked it out yet. Have a nice evening.

 

[boatman]

What’s with the attitude fella?? Was just asking a question, a very valid question on an Internet forum I thought. Unlike your good self im not a professional BMW tech so have no idea why (that’s why I asked) and in answer to your question, no I’ve not worked it out yet. Have a nice evening.

Patience now ,,,,, this fella is one of the best in the U.K. with this stuff ,, he IS helping by getting you to understand what is actually going on

 

[Steptoe]

What’s with the attitude fella?? Was just asking a question, a very valid question on an Internet forum I thought. Unlike your good self im not a professional BMW tech so have no idea why (that’s why I asked) and in answer to your question, no I’ve not worked it out yet. Have a nice evening.

No attitude at all from me Chill, I typed it out with a smile on my face, and explained just how I would as if talking to someone face to face, perhaps if you don’t know me my piss taking humour can be misinterpreted by those of a delicate nature .. perhaps I should thrown in a few smilies

Ok, when you pull the R/H throttle cable all that’s going into the cylinder is more air, no fuel.
The amount of fuel required at whatever the throttle opening is adjusted by the TPS on the L/H side.
Pull only the L/H side cable and more fuel as well as air is supplied.
Pull only the R/H cable and only more air is supplied .
Got it

 

[Pale Rider]

No attitude at all from me Chill, I typed it out with a smile on my face, and explained just how I would as if talking to someone face to face, perhaps if you don’t know me my piss taking humour can be misinterpreted by those of a delicate nature .. perhaps I should thrown in a few smilies

Ok, when you pull the R/H throttle cable all that’s going into the cylinder is more air, no fuel.
The amount of fuel required at whatever the throttle opening is adjusted by the TPS on the L/H side.
Pull only the L/H side cable and more fuel as well as air is supplied.
Pull only the R/H cable and only more air is supplied .
Got it

Good information thanks. Now why couldn’t you have put it like that in the first place, yes now I completely understand

 

[Steptoe]

Good information thanks. Now why couldn’t you have put it like that in the first place, yes now I completely understand

Because I don’t take anything too seriously and like taking the piss and can be very blunt…
I’m a grown up and I don’t mind it given back plus i try to help and guide people think for themselves when working things out

 

[mikeyboy]

I’ll chuck my twopenneth.
The only point at which the balance is important on a big twin is the point at which both throttle butterfly’s open.
3k revs is irrelevant.
Vac gauges connected,very slowly open the throttle.
You’ll see the vacuum drop on the 1st one opening,this is the point where you balance the butterflies.
Out of balance, as you pull away the motor will stutter,low speed stuff will be a pain.

 

[Gee-]

So how come I get back firing when I close the throttle? Fuel farts?

 

[boatman]

I’ll chuck my twopenneth.
The only point at which the balance is important on a big twin is the point at which both throttle butterfly’s open.
3k revs is irrelevant.
Vac gauges connected,very slowly open the throttle.
You’ll see the vacuum drop on the 1st one opening,this is the point where you balance the butterflies.
Out of balance, as you pull away the motor will stutter,low speed stuff will be a pain.

Only time I dropped a GSA 1200 ,, in and of 4 high mileage ( ish ) bikes , was when one of them was badly tuned and it tripped and stalled on a hard turn pull away at low speed ! ( Fella turned out to be all the gear NO idea kinda mech )
Tuned it misen to sort it out ,, should have put it down to Mike in the first place
One hopes the OP appreciates he is getting feed back from 2 of the finest M/C enchineers in the U.K.

 

[theoneandonly]

fuck it ! here is my apeth .
this is how i do a my 1150 ( they aren't dissimilar ).
first check for air leak on inlet side . carb or brake cleaner whilst running.
disconnect throttle cables ( or make sure there is lots of slack )
clean air bypass screws and holes , copperslip and zero the screws.
attach gauges and laptop.
( you've got stepper motors on each ? i'd unplug those , they need to be shut off )
set t/over , via t/over stop screws, to about 900 rpm .
open air bypass screws , to raise t/over to 1000 rpm balancing l&r
connect t-cables or take out the slack , now balance the "pull" as you open the throttle. within 1cm of Hg . i look for them staying the same as you open the throttle . i don't check at 3k but you can if you want i look for evenness.
turn it off , plug the stepper motors back in .
fire it up , the stepper motors will sort out where they want to be , nothing should change , t/over might go up a little depends what spec is .
check tps reading, adjust as needed . i tend to set it in the middle of the range.

back firing ? or a burble ? is tps set too low ? or are you euro 4 ? got an exhaust leak ? or less restrictive silencer ? all these things might do that ?
we are all assuming you did the valve clearances too ?
and the Lambda's are working too ?
F.I. is a juggling act that the bike does . start at the beginning and work through it , do not skip a step.
i have seen many bikes that ran ok-ish , until i plugged in the gauges and the laptop and they were all over the place.

PS, OR you could see if Mark or Bruce would touch it ? ( Twiggers )

 

[Santa-2512]

pops an bangz iz sick mista