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Discussion Starter #1
2005-2006 ZX6R throttle body synchronization guide.
Written by Tweakmon, Oct. 22, 2006



Q: What does ‘synchronizing the TB’s actually’ mean, and what does it entail?
A: throttle body synchronization (commonly referred to as a 'TB Sync') is the process by which you equalize the amount of vacuum the cylinders pull at zero throttle. On the ZX6R, each cylinder has its’ own throttle body, so the four must be ‘synchronized’ with each other to have closest to the same amount of vaccuum as possible. This is done by small pilot screws located in the side of the throttle body.

The purpose of this guide:

It is important to keep the TB’s synced so that the engine will run at its peak performance by maximizing the engine’s intake/output efficiency. A very noticeable difference it will make is the smoothness of how the engine runs, which results in less vibration in the bars. Also, the throttle response will improve as well as idle quality.

Tools needed:

This guide assumes you have the proper tools and mechanical understanding to accomplish the job at hand. It is NOT something that you want to do wrong or your bike will run like junk.

1. Vacuum sync gauges
2. 5-inch long small-bladed flathead screwdriver. (see pic below)
3. Other tools needed for general disassembly of the bike.
4. Special Kawi fuel line extension. Part# 57001-1578 (there is a workaround for this)



If you do not have a factory service manual at this point, go get one. It is your bible as far as this bike is concerned, and there is little you can do properly without it.

STEP 1: Remove the fuel tank (see manual).

STEP 2: Remove the airbox (see manual).

IMPORTANT: If your air filter is dirty, clean or replace it before continuing for most accurate results.

STEP 3: Attach the vacuum hoses to the right-side vacuum ports on the front of the throttle bodies:



Usually the port for cylinder #1 is just a cap, cylinders #2 and #3 have a hose that connects them together then on to the clean air valve, and cylinder #4 sends vacuum to the canister valve. Just disconnect the hoses from #’s 2-4 and connect the vacuum sync tool lines instead. Do NOT disconnect the lines that all intersect and run to the MAP sensor. They are easily identified because they all connect together, and are all the left ports.

STEP 4: Reinstall the airbox (no need to bolt down the front, but do tighten the TB throat clamps.) including all hoses. Make sure the air filter is installed. NEVER run an engine without an air filter.

STEP 5: Reconnect the gas tank so that it will work while allowing you sufficient room to access the TB pilot screws which are located on the rear of the TB's.

Kawi recommends using their special extended fuel line so you can connect the tank sitting on a nearby bench to the fuel rail. It costs about $20 USD, but there is a ‘shade tree’ way. Use a 2x4 that is about 17 inches long to prop up the front of the gas tank. Just pivot it on its’ rear hinge. This will allow you to squeeze around inside long enough to access the pilot screws and adjust them. A flashlight will come in handy.



Now with your vacuum sync tool connected, the airbox back in place and the fuel tank reconnected to allow access to the fuel rail area (rear of TB’s) start the bike up and warm it to at least 180F before continuing. Also, using the power commander software, make sure that the idle stays around 1300 +/- 50 RPM’s. This is important. If it is off too much it will mess with the sync. Readjust it after EVERY pilot screw adjustment as needed.



While the bike is warming up, look at the vacuum gauges and see how far out the cylinders are from each other. Hopefully you connected the hoses in an order so you know which cylinder corresponds to which meter on the gauge.



Our entire goal here is to have all 4 bars of the gauge above to match. If one is higher than the other, it is pulling more vacuum. If one is lower than another, it is pulling less vacuum. The amount of vacuum is not really important. All that really matters is that they need to be as equal as possible. As you can see in the picture above, these are all pretty close to perfectly equal.

If any are out, use the 5-inch long small-bladed flathead screwdriver to adjust the pilot screw that corresponds to the cylinder that needs to be adjusted based on the gauge reading. You can access the screws from behind the TB rack (see pic below)

Rules to remember:

If a particular cylinder is LOW, turn its pilot screw IN (clockwise) to raise it

If a particular cylinder is HIGH, turn its pilot screw OUT (counter-clockwise) to lower it.



IMPORTANT: Adjust cylinders 1-2 to each other, and then 3-4 to each other. If after that sides 1-2 and 3-4 are not all equal to each other, use the screw in the center of the TB’s to equalize the 2 sides (see picture above for locations). Technically, you should never need to touch this center 1-2/3-4 sync screw. Be sure you have synced the individual cylinders properly before adjusting this screw!

Alternate method:

After connecting the sync tool, warm up the bike and then shut it off. Turn all 4 of the pilot screws GENTLY all the way IN, then back them out ½ turn. Start the bike up and adjust all of the cylinders to match the LOWEST one on the gauge.

TIPS:

Don’t turn the pilot screws more than 1/6 of a turn at a time. Always blip the throttle to equalize it and recheck again. Watch the RPM’s on the laptop as well. Keep it at 1300 +/- 50 else the sync will be off! The instrument panel tach is NOT accurate enough for this.

Also, don’t take too long, as the bike will be getting warmer as you work without any air flowing through the radiator. The cooling fan should keep it from overheating, but watch the temp to be safe. You can always let it cool off a bit and finish later. Better yet, blow a house fan through the radiator.


STEP 6: When you have finished and all cylinders are equal, shut the bike off. Disconnect the fuel tank. Remove the airbox, reconnect all vacuum lines, reinstall the airbox. Reinstall the gas tank.

Go for a ride and feel the new found smoothness and throttle response!
 

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cool sounds easy enough. is the pc software idle reading accurate? also what would be any difference in adjusting each throttle body to be equal without using the 1-2/3-4 screw.
 

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Great write up!! About how much do the 4 panel gauges like that run? If you don't mind me asking.
 

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Originally posted by evor1<br>cool sounds easy enough. is the pc software idle reading accurate? also what would be any difference in adjusting each throttle body to be equal without using the 1-2/3-4 screw.
Normally you will never need to adjust the front 1-2/3-4 screw.. You will normally adjust each throttle bodies individual screw separately.

If after adjusting the four throttle bodies cylinder 1-2 and 3-4 won't equal, then you adjust the single front 1-2/3-4 adjustment to equal the left and right cylinder banks out.
 

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Originally posted by the_gooey_1
Great write up!! About how much do the 4 panel gauges like that run? If you don't mind me asking.
Both Tweakmon and I use the Morgan Carbtune Gagues avaialbe from Morgan in the UK - http://www.carbtune.com/ ... It is about $103 which includes shipping from the UK.

The Morgan does not use mercury like most other setups so there is no chance of geting your vaccum so high that it sucks the mercury right into the throttle bodies.
 

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Discussion Starter #6
Originally posted by evor1
cool sounds easy enough. is the pc software idle reading accurate? also what would be any difference in adjusting each throttle body to be equal without using the 1-2/3-4 screw.
Just like awiner pointed out, you never want to touch the 1-2/3-4 screw unless absolutely necessary. Most of the time you will use the individual TB pilot screws to bring them all into alignment. In fact, you will find most of the time there is only 1 or 2 cylinders that actually need adjusting.

The PC3 software RPM tach is about as close to accurate as you will get without using a stand-alone tachometer, which can cost upwards of $100 USD.
 

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Great write up! I need to do this!
 

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according to my 2003-2004 repair manual, you are supposed to adjust the center adjusting screw (1-2/3-4) FIRST. the manual says you need to adjust the highest vaccum from 1-2 to the highest of 3-4. then, use the individual screws to sync all four. also, are you guys counting the throttle bodies 1,2,3,4 from left to right?
 

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Cylinders are counted left to right (1 - 2 - 3 - 4) while sitting on the bike.

If the left (1-2) and right (3-4) TB vacuum is way out of whack you will need to adjust the 1-2/3-4 adjustment to equalize them within a closer range first.

Normally, they will be close and all you will need to adjust is each TB adjustment to tweak the vacuum up or down a few mmHG (or ccHg as the Morgan uses ccHg).
 

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Discussion Starter #10
I would not think you will need to adjust the center equalizer except in a very rare situation, or someone else has messed it up.

It sounds like the 2003-04 manual is a bit different in procedure than the 05-06, however the the basic guidelines should be the same.

I would strongly discourage touching the center screw on the 05-06's unless absolutley necessary. It actually adjusts the butterfly valves and how each side (1-2 and 3-4)opens in relation to each other off idle. This effects the flow and performance across the entire RPM range, and if done incorrectly you will have a crap running bike.

The pilot screws adjust the vacuum levels only. If you do change the butterfly's and get them out of whack, the engine will sputter off-idle even if you sync the vacuums perfectly at idle. How do I know? because I F'ed mine up the first time I did it. It kind of sounds like it is skipping and will make you mad. the vibrations will increase as well.

I ended up having to hold the throttle at 3000 RPM's and adjust the center screw so that there was no skipping. Then I readjusted the idle vacuum sync and all was good.

If the 2004 manual says to adjust the center so that the (2) lowest vacuum cylinders match then bring the remaining (2) into spec it makes good sense, as that is basically what my alternative method says.

I have found it easiest (after you get comfortable with the method) to just turn all of the pilots 1/2 turn from all the way in, warm up the bike and adjust all of them to the lowest reading.
 

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Excellent write up! Thank You!

Just a quick question would you guys be willing to do mine and if so what would you charge? I have a couple of buddies that I ride with and I'm sure they would also want or need to do this.

Thanks
 

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Not to confuse anything we have discussed or describded thus far, however, for reference I am going to quote the entire procedure from the 2005/2006 service manual.


Engine Vacuum Synchronization Inspection

NOTE: These procedures are explained on the assumption that the inlet and exhaust systems of the engine are in good condition.

•Situate the motorcycle so that it is vertical.

•Remove the fuel tank (see Fuel Tank Removal in the Fuel System (DFI) chapter).

•Pull off the vacuum hoses and the rubber cap(s) from the right fitting of each throttle body.

•Pull off the vacuum switch valve hose (thick) from the air cleaner housing.

CAUTION: Do not remove the inlet air pressure sensor hoses on the left fitting of each throttle body.


•Connect a commercially available vacuum gauge to these right fittings of the throttle body as shown.

•Connect a highly accura tetachometer to one of the stick coil primary leads.

•Plug: Vacuum Switch Valve Hose (Thick) and its Air Cleaner Housing Hole Vacuum Switch Valve Vacuum Hose Ends

•Install: Air Cleaner Housing (see Air Cleaner Housing Re-moval in the Fuel System (DFI) chapter), Tachometer, Vacuum Gauge.

•Connect: Extension Tube (Special Tool-Extension Tube: 57001-1578).

•Start the engine and warm it up thoroughly.

•Check the idle speed.

•Open and close the throttle. If the idle speed is out of the specified range, adjust it.

CAUTION: Do not measure the idle speed by the tachometer of the meter unit.

•While idling the engine, inspect the engine vacuum, using the vacuum gauge.

Engine Vacuum Standard: 27.3 ± 1.333 kPa (205 ± 10mmHg) at Idle Speed 1300 ± 50 r/min (rpm)

If any vacuum is not within the specifications, first synchronize the balance of the left (#1, #2) and right (#3, #4)assemblies.

Example:
#1 TB: 165 mmHg
#2 TB: 190 mmHg
#3 TB: 170 mmHg
#4 TB: 200 mmHg

•With the engine at the correct idle speed, equalize the lower vacuum of #3 and #4 (example 170 mmHg) to the lower vacuum of #1 and #2 (example 165 mmHg) by turning the center adjusting screw.

Special Tool - Pilot Screw Adjuster 57001-1292

NOTE: After adjustment, the final vacuum measurement between the lowest throttle valves may not be 165 mmHg (in this example).

The goal is to have the lower two vacuums between the left (#1 and #2) and right (#3 and #4) banks be the same.

•Open and close the throttle after each measurement and adjust the idle speed as necessary.

If any one vacuum measurement is out of the standard measurement after left and right synchronization, turnin the bypass screws until it seats fully but not tightly.

CAUTION: Do not over tighten them. They could be damaged, requiring replacement.

•Turn out the by pass screw of the higher vacuum between #1 and #2 to the lower vacuum.

•Turn out the bypass screw of the higher vacuum between #3 and #4 to the lower vacuum.

•Open and close the throttle valves after each measurement and adjust the idle speed as necessary.

•Inspect the vacuums as before. If all vacuums are within the specification, finish the engine vacuum synchronization. If any vacuum cannot be adjusted within the specification, remove the bypassscrews #1 - #4 and clean them.

Remove the bypass screw, spring, washer and O-ring.

Check the bypass screw and its hole for carbon deposits. If any carbon accumulates, wipe the carbon off the bypass screw and the hole, using a cotton pad penetrated with a high flashpoint solvent. Replace the O-ring with a new one.

Check the tapered portion of the bypass screw forw ear or damage. If the bypass screw is worn or damaged, replace it.


•Turn in the bypass screw until it seats fully but not tightly.

•Repeat the same procedure for other bypass screws.

•Repeat the synchronization.

Remove the vacuum gauge hoses and install the vacuum hoses and rubber caps on the original positions.
 

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Originally posted by awiner
Not to confuse anything we have discussed or describded thus far, however, for reference I am going to quote the entire procedure from the 2005/2006 service manual.

•With the engine at the correct idle speed, equalize the lower vacuum of #3 and #4 (example 170 mmHg) to the lower vacuum of #1 and #2 (example 165 mmHg) by turning the center adjusting screw.
well it looks like the 2005/2006 repair manual is exactly like the 2003/2004 manual. the first adjusting screw you're instructed to adjust is the center adjusting screw. i did mine step by step according to the repair manual (adjusting the center screw first) on my 2003, and everything worked fined. it seems tweakmon had problems using the center adjusting screw on his 2005 model. i must agree with tweakmon, unless you're throttle bodies are WAY out of sync, don't touch the center adjusting screw. this was my first tb sync at 16K miles so mines were WAY off, requiring adjustment in the center screw. good luck.
 

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Discussion Starter #15
UPDATE:

I have devised an even better way to get your sync balls on in no time!

1) Turn the TB pilot screws all the way IN until they seat. Do this carefully and lightly.
2) start the bike and get it up to 180+ degrees.
3) Run the RPM's up to about 6-7k and look at your vacuum gauges. If the readings are all right about even, you are good and can skip to step 5.
4) adjust the center 1-2/3-4 screw and run the RPM's up again until the gauges all read about equal at about 7k RPM. Most important, make sure the LOWEST one out of 1-2 and the lowest out of 3-4 are about even with each other.
5) Now at idle (1300+/-50 RPM...get as close as you can to 1350) adjust the pilot screws to make all cylinders equal with the LOWEST reading of all 4 cylinders.
6) Put the bike back together and go raise hell![:p]

I did this method yesterday and all I can say it fuc-n-ay! EVERY RPM is super smooth with almost zero vibration. Feels like a whole new bike. Forget what the Kawi manual says. This method makes a lot more sense to me anyways.

On the way home tonight I gunned it on the 405 just to check the smoothness > 12k and when I looked down I was doing 127 instantly. NO VIBRATIONS ANYMORE AT ANY RPM. Well, atleast not more than normal slight engine vibration. the throttle response is up as well.

My bike has not run this smooth in 16k miles. try it!
 

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i'm going to try your method
even though my 03/04 repair manual says to adjust the highest of 1/2 to the highest of 3/4

just to clarify:
are you holding the throttle at 7k rpm and adjusting the center screw?
or do you rev, let go, then adjust?
 

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Discussion Starter #17
Hold the revs for a couple seconds until the gauges settle. Then adjust the screw at idle and run them up again. I believe on the 05 turning the screw INWARDS raises cylinders 3-4. Recheck until the (2) lowest of the pairs are even. Now you know all throttles are opening evenly off idle.

You already have the pilot screws bottomed all the way in...turning them out only lowers the vacuum for that cylinder, so you will want to lower the remaining vacuums to be even with the lowest of all 4. Then you know the cylinders are all pulling even vacuum both at idle and at midrange. Gonna be hard to even them out any more than that.
 
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