2000 R1100RT throttle body sync

I am performing throttle body sync and am having problems with the high speed adjustment. The idle speed sync seemed ok, but when I increase rpm the column on the right cylinder begins to rise . Both throttle cable adjustment screws are nearly bottomed out and I can't seem to make any adjustment that brings both columns equal. Do I need to go back to the air adjustment screws on the throttle bodies or am I missing something? I am doing this procedure using a home made manometer.

littledog said:

I am performing throttle body sync and am having problems with the high speed adjustment. The idle speed sync seemed ok, but when I increase rpm the column on the right cylinder begins to rise . Both throttle cable adjustment screws are nearly bottomed out and I can't seem to make any adjustment that brings both columns equal. Do I need to go back to the air adjustment screws on the throttle bodies or am I missing something? I am doing this procedure using a home made manometer.

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IIRC that model uses a distribution block, with the cable from the throttle grip going into a junction box and a cable to each TB coming out of the junction block. The high-idle (“choke”) cable also feeds into that junction block.

The air bleed screws are the only adjustment that should be touched for syncing at idle; you do not want to touch the stop screws which are likely marked with blue paint. But first, check how much free play exists at the throttle cable ferrules on the TBs. I usually set to 1.0mm-1.5mm or so of free play. With that set and matched, and the idle sync completed via the brass screws (air adjustment screws), it should take very little adjustment of the throttle cable ferrules on the TBs to have both sides picking up equally. Some find it easiest to adjust one ferrule only (which was the RH one on the original single-cable R1100s) while others adjust both sides but in opposite directions. Either way, you should be able to get an even rise without gross adjustments while still maintaining free play on the ferrules at idle.

Double-check your connections and verify that you do not have any air leaks or blockages in connections or apparatus, and check the spigots on the TBs to make sure they are not plugged—it sounds like your left one may be suspect.

HTH,
DeVern

First, make sure that there is some free play on the throttle cable’s for both sides.

You are performing two mostly independent TB syncs. The BBS, the air bypass screws, are used to only balance the TBs at idle. Above idle, the throttle cables are adjusted to make them in balance. Make sure both sides are hitting the stops when you release the throttle. Loosen the locknut on both cable adjusters. Raise the rpm a little, maybe 1500, and take note of where the fluid level sits on your manometer. If the right column is higher, try adjusting the left side adjuster counter clockwise. Make a small adjustment, bring the rpm back to 1500 and see how it compares to the earlier measurement. Make sure that you don’t remove all of the free play. Once you seem to have balance at 1500, it should remain in balance at higher rpm.

m_stock10506 said:

First, make sure that there is some free play on the throttle cable’s for both sides.

You are performing two mostly independent TB syncs. The BBS, the air bypass screws, are used to only balance the TBs at idle. Above idle, the throttle cables are adjusted to make them in balance. Make sure both sides are hitting the stops when you release the throttle. Loosen the locknut on both cable adjusters. Raise the rpm a little, maybe 1500, and take note of where the fluid level sits on your manometer. If the right column is higher, try adjusting the left side adjuster counter clockwise. Make a small adjustment, bring the rpm back to 1500 and see how it compares to the earlier measurement. Make sure that you don’t remove all of the free play. Once you seem to have balance at 1500, it should remain in balance at higher rpm.

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I'm gonna disagree that sync at 1500 RPM carries through RPM range.

You spend infinitely more time on the throttle than at idle, therefore, worry less about idle sync and more at the 4000-5000 RPM range.

As others have mentioned, make sure you start with lots of slack, both cables, take your time, be patient.

Make sure you got lots, as in tons, as in blow you away airflow over the engine while you try to be patient.

If you discover the magic formula to being patient, PM me.

I have checked throttle cable free play on both sides, throttle stops are bottoming out, no debris on throttle wheels, manometer connections are tight. I tried turning left adjuster but the right cylinder pulls fluid up the column right off idle. I am wondering if it is something else like a plugged spigot. Where is this located and how do I check/clear it? I have done the throttle body sync before and did not have any issues like this.

Free play is not the issue. You need to adjust off-idle synch by adjusting the amount of play in one side to match the other.

I am assuming that since the right side cylinder pulls fluid first then the throttle body on that side is opening first. Therefore I need to loosen that throttle cable and/or tighten the left side cable. Is this correct?

littledog said:

I am assuming that since the right side cylinder pulls fluid first then the throttle body on that side is opening first. Therefore I need to loosen that throttle cable and/or tighten the left side cable. Is this correct?

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I don't understand "pulls fluid". What are you using as a vacuum measuring device?

Diesel yoda was right. It takes a little patience. I was wrong in my assumption that I needed to loosen the right cable. After turning the cable both ways I discovered I needed to tighten the right cable. I am now satisfied that the throttle bodies are properly balanced. Thanks to all for your input.

Sorry,Paul. I didn't see your question. I am using a homemade manometer. 1/8 tubing secured to a 1x2 with ATF.

littledog said:

Sorry,Paul. I didn't see your question. I am using a homemade manometer. 1/8 tubing secured to a 1x2 with ATF.

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Ok. They work. I'm glad you got it sorted out.

TB balancing

m_stock10506 said:

First, make sure that there is some free play on the throttle cable’s for both sides.

You are performing two mostly independent TB syncs. The BBS, the air bypass screws, are used to only balance the TBs at idle. Above idle, the throttle cables are adjusted to make them in balance. Make sure both sides are hitting the stops when you release the throttle. Loosen the locknut on both cable adjusters. Raise the rpm a little, maybe 1500, and take note of where the fluid level sits on your manometer. If the right column is higher, try adjusting the left side adjuster counter clockwise. Make a small adjustment, bring the rpm back to 1500 and see how it compares to the earlier measurement. Make sure that you don’t remove all of the free play. Once you seem to have balance at 1500, it should remain in balance at higher rpm.

Click to expand...

The point made here by you about this part of the balancing is important. I haven't actually seen this addressed before. I used this method to fine tune the TB's and it works very well. The last step is to use the BBS to adjust the idle to where it needs to be while checking to make sure that the TB's stay balanced. THANKS!
Greg