My 2014 ZX14R is reaching 7500 miles soon and one of maintenance item is throttle body sync. Some of my friends say "Some shops don't even do it but still charge you because it is hard to tell unless the sync is totally out of spec to begin with". In the past, I have done throttle body (carburetor sync back then) on CBR600F2 once but didn't feel much difference. I had San Jose BMW (a reputable shop in this area) did the sync on R1100S but didn't feel much difference. So the bottom line is if I don't have to do it, I don't want to do it. I am already busy enough and want to minimize work on ZX14R. I will replace spark plugs and oil/filter for sure, though. What would be negative consequences of not syncing the throttle body? A rough idling? Non linear acceleration?

I'm certainly not the expert on this but I did go through the process on my '06 after I adjusted the valves at 15K. My understanding was that the sync was a general service task that went with the valve adjust. Seem logical to me due to the change in flow from the change in valve clearance.

The adjustment was a major PIA. Rook created a great thread on his experience - search for that, it's the most info I have seen and I wish it was available when I did mine.

The shop should have an instrument to set the vacuum level as well as balance the TB. I used the Motion Pro sync tool where you only can adjust the relative level to be equal across the TB.

As far as before and after - and I had 50% of the valves a bit out of spec- no noticeable difference that I could tell.

What would be negative consequences of not syncing the throttle body?

A rough idling?

Non linear acceleration?

Just by setting both shafts [alone] has a Big time throttle response. You're missing the Big Picture between a carb vs. injector response. Do it!

I'm no expert either but my experience was no real improvement/change in idle or throttle response at any rpm or throttle position. The bike ran good before and it ran good after. It's hard to quantify how much it was out of sync because I started off using a manometer instead of vacuum gauges but by the look of the fluid collums, mine was pretty OUT of sync before and had never been adjusted in 47,000 miles. Still ran good as new. I recently watched a tutorial that suggested synching at higher rpm instead of idle to get smoother running at highway speeds. Sounds like that might be something to try but then again, my bike already runs smooth at highway speeds and it did before the sync too.

I'm still dallying with transferring data to the new computer but if necessary, I can post the tutorial I have created. just let me know if you need it.

Here is the thread rudy was speaking of. LOL reading that is enough to make anyone decide to not do it but the tutorial would give you all the tricks to demystify the whole process....still a lot of work even if it's all laid out for you.

 http://zx14ninjaforum.com/messages.cfm?threadid=6B8DE3C8-1372-66AE-3BBE8C19C36BB342&searchTerm=throttle%20bodies%20sync&page=1

I seem to recall that the Gen2 does not have that pesky center screw and that might make this a little easier than the Gen1 right off. There would still be junk to get out of the way and the Gen2 is even more cramped than the Gen1. That would probably be more of a problem for reaching the test nipples on the Gen2 than it would for reaching the screws.

* Last updated by: Rook on 2/8/2016 @ 8:56 PM *

When I did the sync at 7500 miles it seemed to make a very slight difference. It might have just been in my head. A lot of people said it's temporary though and after a short time they'll fall out of sync again anyway. This seemed to be the case. Throttle seemed slightly snappier just after the sync, but overall I'm not sure it really made any actual difference.

Gen 2s do have the same center screw, however you are to NEVER adjust it where as with Gen 1 you are encouraged to adjust it when called for. Not sure why the difference but Kaw even states adjusting it calls for replacing the entire TB assembly because it's set at the factory.

The majority of difference in having the t-bodies synced is at idle. Once the butterflies are open the small differences in opening is virtually non existant.They'd have to be WAY out to make the motor suffer.

Mad

WOThe Fuck?

1. Crank Jerk Pulse = out of sync.
2. Clutch Bang Bellow = out of sync.
3. Chain Slap Shit = if chain is the crank to main shaft transfer.
4. Gear Bang Bump = if no chain is used, here comes the pulse out of sync.

Gen 2s do have the same center screw, however you are to NEVER adjust it where as with Gen 1 you are encouraged to adjust it when called for. Not sure why the difference but Kaw even states adjusting it calls for replacing the entire TB assembly because it's set at the factory.

Brass = Gas will chemically eat this material so factory says to replace with new on a rebuild.
Air Bleed = Now that you have new needles, book says to count the turns and note so you can replace the rebuild parts back to factory.
Center Sync Screw = The most sought after screw is the center with 2 opposed shafts that call the BANG-PULSE!
Air Screws = I start a thread at 2 o'clock, my turn out is not balanced with a thread started at 3 o'clock reference say.

Pulse pulls air thru every open hole out of that carb body is air-low-main is a constant linear blend.
Pulse pulls air thru the one air screw in the throttle body is lean-lean-lean the more you open the needle.
Pulse pulls air thru a balance of 3 vs. 2 o'clock feed bleeds and throws off the blend/balance of air entered.
Pulse pulls air thru half an open door or the door is wide open, show me the pressure flow I use water thru those gaps... Oh, I see now! I can walk it as it talks. No book needed.

Amateur: Homes the air screw and cuts a groove around the taper of the needle.
Expert: Never homes a needle but uses a manometer to sync a closed screw, feels the rubber ring collapse, or has a gorilla hand at the end of the screwdriver to collapse the taper in the throttle body/carb body and ruin the unit.
Now change the fucking body assembly.

But for someone to say the book says to toss the body because you touched a center sync screw? Who comes up withishit?
I ran so many AFR settings using the air screws is that blend of air vs. AFR.
I ran my first computer sync ever was that gen1. Never saw a change in throttle yank was that response was so impressive. It went from a slight lag to oh shit I almost hit the limiter!

The fucking bike shit you hear on the net is fallacy from the word go.

because it's set at the factory.

You should have figured that out, but you're an input guy, I'm more the digital guy inside the box and here is your output is junk in is junk out. If you do not get the penultimate number before that valve closes> use is lost. One handcuff after the other it's so absolute is how it's magnetically forced to work that way is this environment we are handcuffed to.

WATT HUBSAY? Hub said he was having fun with Vic's interpretation of how that book is read to how in the field it reads something else. As if a perfectly running 100 point vette with its mechanical fuel injection needs a new body. As if a 100 point model T still using the OE parts needs the carb changed. As if all those used brit amals going thru everyone's hand and butchering those tapered holes: they too still flow the same AFR is all. Blend is blend and balance is balance.

Signed,
I've come to take your Trophies is that throttle sync is about to fuck your day up... some of you 1/4 milers.

P.S.
Ever heard of those CB750's or say your classic, 'I pull the clutch in and the noise goes away?' Got enough clues yet to trump your whack?

I seem to recall that the Gen2 does not have that pesky center screw and that might make this a little easier than the Gen1 right off.

Design wise this is the same 1 piece body for 2 cylinder banks and 2 shafts for 4 cylinders. They only way to sync the shafts is that center screw.

* Last updated by: Hub on 2/9/2016 @ 10:26 AM *

Amateur: Homes the air screw and cuts a groove around the taper of the needle.
Expert: Never homes a needle but uses a manometer to sync a closed screw, feels the rubber ring collapse, or has a gorilla hand at the end of the screwdriver to collapse the taper in the throttle body/carb body and ruin the unit.
Now change the fucking body assembly.

* Last updated by: Rook on 2/9/2016 @ 4:19 PM *

If your tb synch is off, you will hear more mechanical noise as the faster cylinder(s) fight the slower one(s). The farther out is is, the more rattling you'll hear. It has to be out quite a bit to noticeably affect performance, at least on the seat-of-the-pants dyno.

have a look at the second pic on step 9 here. the tape idicates where the vacs were pre-sync. The adjustment made no discernible dif.

http://zx14ninjaforum.com/messages.cfm?threadid=B22DF8A8-C4B9-08CF-873FF5D76B02C7D4

actually, I would suggest you get vacuum gauges as shown in the other pics on that thread. The Sync-Pro is not a very good manometer compared to the British one that I have seen which uses mercury and does not need calibration and has mmHg increments. It is not easy to find in the US.

You could check it but unless you want to just do it for kicks, I would not bother to adjust unless it's seriously out of sync and the bike idles poorly.

* Last updated by: Rook on 10/31/2016 @ 7:28 PM *