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#537535 - 11/08/09 03:41 AM Re: Throttle Body Sync using GS-911 [Re: Ken H.]  
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KDeline Offline
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KDeline  Offline
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ignore the idle and adjust the right side cable for best sync above idle.
[/quote]

Why does the right side seem to be the one to adjust?

#537550 - 11/08/09 08:41 AM Re: Throttle Body Sync using GS-911 [Re: Mike T]  
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SWB Offline
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Well, I just did my first R1200RT sync (as compared to my old R1100RT). I more or less followed the a "modified Von Baden", i.e. without the GS-911 because I'm too cheap to buy one. wink However, since this thread discussed TBS sync in general, I thought I'd toss my experience into the discussion.

  • Warmed up the bike to operating temps.
  • Pulled the plug and shutdown power for about 5 minutes.
  • Disconnected the stepper motors
  • Reconnected the battery, turned on the ignition (but didn't start the bike), opened the throttle full twice reset the computer and then powered down.
  • Hooked up the Twin max and calibrated - sensitivity on high. Set sensitivity to low.
  • Loosened the lock nuts on both throttle body cables.
  • Started engine. Backed off left screw and then tightened it until the Twinmax needle JUST started to move, then backed it out one turn. Did the same to the right side. Tighted the lock nut on the left side cable.
  • Engine ran ROUGH, as expected. Did my best to sync at idle. Shutdown engine. Hooked up the stepper motors.
  • Restarted the engine. Better at idle, and improved over time as the computer and steppers relearned their optimum position at idle and adjusted (presumably).
  • Worked on sync from 2K, 3K, 3500K, 4K, while adjusting the right throttle cable. Did it again. And again. More times. Needle moved "left" when I tightened, and "right" when I loosened. Couldn't get it to consistently stay on "zero" at 3500K. Throttle cable adjustment is VERY sensitive. Just a little bit of tension on the nut or cable changes sync a whole lot.
  • No matter how much I loosened the right side to pull the needle from left to center, it didn't seem to be enough. That's when I figured "heck, the left cable must be way too loose or too tight, because the right side isn't responding". So, I unlocked the nut on the left side and sure enough, after I tighted it a quarter turn and locked it, the right throttle screw was more responsive. I could adjust the needle left to right and center.
  • After more fiddling, I discerned a consistent pattern. Accelerating from 2K through 4K, the needle would move from left to right. I could sync it up at a given point, but it wouldn't "hold" sync throughout the throttle range.
  • I finally locked it in at 3500K, and that was "it" for today.
  • Finally, +1 to the guys saying find a very thin 10mm wrench for the lock nut. Was a real *** trying to get a wrench in there. I finally held the throttle cable nut "over the top" with a large pair of pliers while I used my "fat" 10mm to tighten the locknut. A REAL hassle since just the slightest movement of the cable adjusting nut messes with the sync in a very noticeable way. Need to find me one of those 10mm wrenches on a diet.


The bike runs strong, starts well, idles OK. However, I don't think it's quite to "spec". From experience with my old R1100RT, I'm pretty sure I have one or more problems with this 2005 RT with 48K miles on the odometer. When I reset the valves, I found one has a damaged lock nut (or valve stem bolt - whatever they call those thingys). That made setting clearance and getting it to "stick" on that intake valve difficult. Other than that, it was a very easy adjustment. I checked rocker arm shaft end clearance, which was anywhere from 0.10mm to 0.20mm, well within the 0.05mm to 0.40mm spec. (Wasn't happy with it, particularly because the variance was considerable from left to right on the same cylinder, but will wait to next tune up to reset it).

I'm guessing that either my valves aren't set exactly right, or I've got some sort of vacuum leak or other mechanical defect someplace. I handled this kind of situation on the R1100RT by replacing all "O" rings on the intake systems, de-coking the throttle bodies, replacing the throttle cable and bowden box, i.e. making sure everything on the intake was clean and tight. I'll probably do that next tuneup as well, AND fix the messed up valve adjuster if I can do it without major engine work.

Other than that, I don't know why the throttle balance would "pull" from left to right as the throttles both increased. They're obviously not pulling evenly or together, but it's not a real bad situation, i.e. less than half a notch left to just a bit to the right over about a 3K RPM range.

Maybe I'll have to sponsor a Tech Daze at my house for the Southern California riders; price of admission will be someone bringing out their GS-911. I'd love to compare the difference. grin

- Scott

#537581 - 11/08/09 01:53 PM Re: Throttle Body Sync using GS-911 [Re: SWB]  
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Peter Parts Offline
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My 2-cents.

Not helpful tuning no-load in your driveway. You are "tuning" only the first 1/8 inch of throttle (or coupla degrees of butterfly) and the map cell for no-load for say, "4000 rpm at 3 degrees open" is wonkee if not entirely undefined on the ECU map.

While a vacuum gauge is a bit more sensitive than a TwinMax (you read it here first), you may be interpreting tiny changes which vary with the weather and all at near-idle butterfly angles. And you can eliminate some of low-throttle imbalance with a TB to TB cross-over - automatically and forever.

TwinMax gives you only non-scaled relative values while dual vacuum gauges give you relative and absolute.

Go riding with dual vacuum gauges.

Last edited by Peter Parts; 11/08/09 01:56 PM.

R1100S, 1999 (don't know much about other models)
Riding 52 years but only last 47 on BMW boxers
Bike writings: http://www.tinyurl.com/6bvt23
(includes a 6400 mile trip, 20 days, with wife to LA)
#537621 - 11/08/09 04:44 PM Re: Throttle Body Sync using GS-911 [Re: KDeline]  
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Ken H. Offline
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Originally Posted By: KDeline
Why does the right side seem to be the one to adjust?

You’re trying to get a tracking match between the two, there’s no point in adjusting the left one, you just end up chasing your tail. ISFA why the right side, I suspect it has to do with tradition as much as anything, going all the way back to the 1100 series where position of the TPS on the left side at idle was critical. The approach has continued to this day, if for no other reason that constancy in procedures from model to model.


Ken & Donna H.
Doctor – I need to learn how to relax faster.

If you want to ride tomorrow, ride quietly today.
Quiet is cool, silent is sexy.
#537624 - 11/08/09 04:52 PM Re: Throttle Body Sync using GS-911 [Re: Ken H.]  
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Speaking of using the GS911. When I used it we watched the lambda air sensor graphs and they looked a bit wild. Are they supposed to track each other? What are they supposed to look like? One had sort of a saw tooth and the other had flattened peaks. However the engine performs well.


Joe

'05 R1200RT 109K miles, takes me down the highway.
'13 KTM 690 Enduro R 16K miles takes me through the woods.
#537643 - 11/08/09 06:06 PM Re: Throttle Body Sync using GS-911 [Re: Ken H.]  
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KDeline Offline
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KDeline  Offline
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Originally Posted By: Ken H.
Originally Posted By: KDeline
Why does the right side seem to be the one to adjust?

You’re trying to get a tracking match between the two, there’s no point in adjusting the left one, you just end up chasing your tail. ISFA why the right side, I suspect it has to do with tradition as much as anything, going all the way back to the 1100 series where position of the TPS on the left side at idle was critical. The approach has continued to this day, if for no other reason that constancy in procedures from model to model.


O.K. that is what I thought I read sometime ago, probably on this site. I only set one cable to the other, aways the right, after checking the free play on the left.

#538111 - 11/09/09 09:09 PM Re: Throttle Body Sync using GS-911 [Re: Ken H.]  
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Jim VonBaden Offline
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Originally Posted By: Ken H.
Originally Posted By: KDeline
Why does the right side seem to be the one to adjust?

You’re trying to get a tracking match between the two, there’s no point in adjusting the left one, you just end up chasing your tail. ISFA why the right side, I suspect it has to do with tradition as much as anything, going all the way back to the 1100 series where position of the TPS on the left side at idle was critical. The approach has continued to this day, if for no other reason that constancy in procedures from model to model.


AND, the right side is easier to get to to adjust. That, and if you never mess with the left side, you wont tend to reduce the slack, so it wont need adjusting.

To the OP, if your sync keeps wandering as your engine speed changes, you likely have a vacuum leak. Possibly in your intake boots.

Jim cool

#540343 - 11/16/09 07:41 PM Re: Throttle Body Sync using GS-911 [Re: Mike T]  
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Mike,

Been discussing this with Stephen (Mr GS911) quite a bit, and swapping log files and screen captures.

What we have found - some hexheads - the stepper motor positions will vary at idle (one open more than the other.) This appears to be dynamic - they change on the order of 30 second or so intervals. We do not know what triggers the changes. (Edit: I should note - if I disconnect one of the vacuum lines to a TB - there will be a reaction on the part of the stepper positions - so something is sensing what the engine is doing in real-time.)

Above idle - the stepper motors seem to lock-sync in STEPS. If the step count is out (which is entirely possible since there is no feedback from the steppers to the ECU and they can drop counts) - what shows as being the same opening might be different openings in reality.

The stepper zero-adjustment assumably puts the stepper motors back in sync by fully closing them and then zero'ing out each sides step counter. IF your steppers had lost steps - even when the ECU thought they were both open the same amount, they might not be, and if so - you've now "balanced" the TB's to compensate.

Ideally - you want to use the GS-911 or an equivelent, that before allowing you to do the balance first zero's the steppers, then locks them at a set open position.

I believe the calibration of the steppers combined with an accurate TB sync is what improved the performance for you.

Last edited by Don_Eilenberger; 11/16/09 07:42 PM.

Don Eilenberger
'12 R1200R - Love this bike!
Spring Lake, NJ
#540525 - 11/17/09 03:53 AM Re: Throttle Body Sync using GS-911 [Re: Don_Eilenberger]  
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graydude Offline
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I have not been this confused since that night in college..er...sorry, wrong forum. Steppers, GS0911, what the hell!! Can the average shade tree mechanic adjust the TB's or not?? Are these extra steps in the procedure really necessary are will they simply go from 90% acceptable to 98% acceptable? I'm ready to swap in a Briggs and Stratton and be done with it.


IBA#22266


05 K1200 LT,

Real bikes have radiators



"Dry Town Crew" in training
#540639 - 11/17/09 04:13 PM Re: Throttle Body Sync using GS-911 [Re: Don_Eilenberger]  
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Mike T Offline
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Thanks for the input Don. I think your explanation on the GS911 syncing the stepper motors makes sense. I used to balance the TBs without the GS911(and without disconnecting the stepper motors) and did not see much difference in performance even if the TB's needed some adjusting at off idle. It was almost like the stepper motors would compensate for the adjustment I was making in the cable thus keeping the balance (and performance) the same as before adjusting. I could be way off base here but that's what it seemed like.

After using the GS911 to zero (sync) the stepper motors the bike runs smoother (although I did not consider it not smooth before) and requires much less throttle to get moving.

Thanks again for all the input.


Mike T.

'95 R1100RS
'06 R1200RT
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