Post Throttle body sync question (Idle Adjustment)

[EEL]

Ok so this one's for the guys who actually sync their throttle bodies:

I finished syncing the throttle bodies (yes, motor was up to operating temperature, sync'd at 5k rpm)

Now here's the question: how do I adjust the idle?

1) Do I need to sync the idle too or can I just back the idle adjusters out the same amount of turns on each throttle body.

1a) If I need to sync the idle,how to I do it? do I just keep my manometer plugged into the sample ports and try to balance at idle? Currently the bike idles fine but I want to know how to do it right.

Thanks in advance

PS...I have an 05 S2R 800.

[EEL]

No one?? Am I in uncharted territory here?

Bump

[Howie]

Normally synch is done at idle and idle speed is done with the air bleeds by turning in or out equally.  Individual adjustment of the bleeds would be done to balance CO if needed.  Then you would go back and synch at idle if needed.

[pennyrobber]

Did a TB sync recently on my bike. The TB's were pretty close at idle before the sync but went way off once throttle was applied. We got the things synced across the rev range as good as possible. Figuring you spend most of your time riding between 4000 and 6000rpm, it would make sense in my opinion to have the TB's synced for that rev range. After sincing the TB's we went back and set the idle.

[EEL]

Howie,

I think you're misunderstanding the meaning of a throttle body sync.
At idle, throttle bodies are not even open. hence you cant really sync them. Air comes in thru the set screws.

That being said, I appreciate the response, you indirectly got me to visualize the intake system in my head and come up with the answers to my initial questions.

Pennyrobber

You're right. I sync'd my TB's at 5k. In order to do this properly you have to close the idle adjusters first. When I finished syncing the TB's I had to reopen the idle adjusters. I turned them out to equal amounts.

Based on the explanation I gave to howie, I think turning them to equal amounts was the wrong thing to do. I think I need to balance the idle adjusters very much like balancing TB's like howie indicated.

After thinking about it a little more idle adjusters serve a dual purpose. They regulate idle but they also regulate the power pulse when you close the throttle at for example highway speeds / 6th gear.

I counted the turns on each idle adjuster before I closed them. They were drastically different from the factory. I'll readjust today and see if it makes a difference.

[Speeddog]

At idle the throttles *are* open a tiny bit.

You can sync it at 5k rpm with the screw between the throttles if you want, then adjust idle speed and sync with the throttle closed, using the bleed screws.

[pennyrobber]

At idle the throttles *are* open a tiny bit.

You can sync it at 5k rpm with the screw between the throttles if you want, then adjust idle speed and sync with the throttle closed, using the bleed screws.

Essentially what I did the other day. The bike is running noticeably smoother now.

[Howie]

Howie,

I think you're misunderstanding the meaning of a throttle body sync.
At idle, throttle bodies are not even open. hence you cant really sync them. Air comes in thru the set screws.

That being said, I appreciate the response, you indirectly got me to visualize the intake system in my head and come up with the answers to my initial questions.

Pennyrobber

You're right. I sync'd my TB's at 5k. In order to do this properly you have to close the idle adjusters first. When I finished syncing the TB's I had to reopen the idle adjusters. I turned them out to equal amounts.

Based on the explanation I gave to howie, I think turning them to equal amounts was the wrong thing to do. I think I need to balance the idle adjusters very much like balancing TB's like howie indicated.

After thinking about it a little more idle adjusters serve a dual purpose. They regulate idle but they also regulate the power pulse when you close the throttle at for example highway speeds / 6th gear.

I counted the turns on each idle adjuster before I closed them. They were drastically different from the factory. I'll readjust today and see if it makes a difference.

Remove the screws (20) from intake
manifolds and install couplings (7) in
the seat of screws (20).
Fully tighten and close the by-pass
screws (19). Start the engine and run
it slightly fast.
Press "Start" to start the pressure
measurement in the cylinders.
The page shows an indicator (E) that
turns red when the function is active.
Values can be displayed as numbers
or as graphs, press "Display mode" (F)
to select the display mode.
Turn screw (21) to balance vacuum:
remove the airbox-throttle body
(Sect. L 6) to gain access to this
screw.
Vacuum is balanced when the two
lines on the graph overlap or when
the two values are equal.
Press "Reset" to reset the values.
Open the by-pass screws (19) of each
cylinder and set them to read an idle
speed of 1250±50 rpm. The value can
be read in "Engine Electronic system":
refer to "TPS reset" procedure.
Connect an exhaust gas analyser to
the exhaust pipe take-up points using
fittings (22) part no. 88713.1010 and
measure the CO rate of each cylinder.
If the percentage is outside the
specified value (1.5% Vol.), adjust the
trimmer.

This is from a manual for your bike without the diagrams.  They use the DDS of course, but you can subsitute you favorite tool.  Checking synch at 5k is fine, but synch should be pretty much the same throughout the RPM.  range, if not, there is a problem.  As Speedddog said, the throttle plates are slightly open, they are on all throttle bodies.  As long as they are open there is flow.  Balancing with the air bleeds is a CO adjustment. 

A trim adjusment to 4-4.5% instead of 1.5% will make a difference.