Throttle Body Sync to fix vibes? Anybody done it or had it done?

[JetJock]

My 2010 C14 has a really bad case of the vibes at the bars/levers and with my new and longer commute, very noticeable. Starts at 3500 rpm and continues into the low 6K mark, right in the meat of the powerband. And this ain't "mild" making power tingles, but finger-numbing continuous vibes.

A customer and someone who also has the same year C14 said to have the throttle bodies synced as he'd had it done on another C14 (a car hit the other bike, so he got another one). Swears it fixes the vibe problem that some of us have and some of us don't.

Thing is, when I called the dealer for an appointment to have this done, they go "We've never had anyone ask to have the throttle bodies synnced and not even sure it can be done." REALLY? I don't think so.

So I pull out the Service Manual, and of course the dealer service guy is wrong, as there are 3 pages of how-to sync the throttle bodies.

Anyhow, the question here is whether anybody on this forum has had this done and seen a reduction and/or elimination of vibes at the bars?

[B.D.F.]

Many of us have done it / had it done. Some have reported vibration reduction but it does not seem to be many. I personally have not noticed any difference.

The thing to remember is that synching the T.B.'s is only an idle function and once the bike is at 3,500 + RPM, the throttles are open far enough away from idle that the air bleed adjustments (what is done to synch. the T.B.'s) does not have much, if any, effect.

The C-14 does not vibrate badly but the vibes it has are high frequency vibrations, known as 'buzz' it it does tend to put your hands to sleep. On the ones I've ridden, it is the right handlebar that is worst- you know, the one you cannot let go of :-(   The cure for a lot of us was either a throttle lock or a cruise control; that will allow you to 'let go' of the right bar often enough and for long enough to stop it from annoying your hand. You do not have to [not touch] the handlebar, you can just relax your hand on top of it for example and that is enough to stop the discomfort.

Brian

My 2010 C14 has a really bad case of the vibes at the bars/levers and with my new and longer commute, very noticeable. Starts at 3500 rpm and continues into the low 6K mark, right in the meat of the powerband. And this ain't "mild" making power tingles, but finger-numbing continuous vibes.

A customer and someone who also has the same year C14 said to have the throttle bodies synced as he'd had it done on another C14 (a car hit the other bike, so he got another one). Swears it fixes the vibe problem that some of us have and some of us don't.

Thing is, when I called the dealer for an appointment to have this done, they go "We've never had anyone ask to have the throttle bodies synnced and not even sure it can be done." REALLY? I don't think so.

So I pull out the Service Manual, and of course the dealer service guy is wrong, as there are 3 pages of how-to sync the throttle bodies.

Anyhow, the question here is whether anybody on this forum has had this done and seen a reduction and/or elimination of vibes at the bars?

[MAN OF BLUES]

As Brian noted, some folks had better results, some had none, its a coin toss till you stick the gauges on... I think a valve adjustment makes more effect, combined with new airfilter. Either way, synching without doing those steps is knda moot,  t/b's don't just "go outta synch" by themselves, they were either off from the beginning, or because the valve clearances have changed, and once they are put back into correct spec, the original synch should be restored... jmho.
After I did my adjust synch was spot on, but while I was doing the adjust and had everything removed, I installed hoses routed out to the left side, and capped them, just in case I wanted to check again later... makes it much easier, as they are a biotch to get on with the stuff all attached and in the way...
Oh, that dealers response is typical, and they prolly never did a valve adjust on a C14 either...just saying...

[Rembrant]

My 2010 C14 has a really bad case of the vibes at the bars/levers and with my new and longer commute, very noticeable. Starts at 3500 rpm and continues into the low 6K mark, right in the meat of the powerband. And this ain't "mild" making power tingles, but finger-numbing continuous vibes.

Might be worth going through the engine to frame bolt torque sequence to make sure it's all up to snuff and correct.

I checked my 2010 C14, and it was definitely out....out enough that one of the front engine bolts wouldn't go back in until I loosened the whole bracket (which you have to do anyway, but still...something was out of whack).

Rem

[martin_14]

to the OP: check if there are washers between the handlebars and the end weights. That happened on mine, and a 50 cents washer at each end cured the issue.

(where's Maxtog when you need him telling that there's been posts about this and you should use the search function?  )

[jwh20]

The inline 4-cylinder engine has what is called PRIMARY BALANCE by benefit of its design, so unlike a V-twin for example, they are generally smooth.  But they all suffer from a slight secondary imbalance as a general characteristic.  This is the purpose of the engine balancer that is in some inline 4 bikes including the C14.

The problem with secondary imbalance is that it's at 2X the rpm so it is often described as "buzz".  While carb and TB imbalance can cause it, I agree with the others that at the rpms you are talking about, that's probably not it.

You might check the balancer and this is adjustable.  It's possible it's not "tuned" just right for your bike.  The procedure is in the Svc Manual but you can also get a feel for it here:

http://zzrbikes.com/threads/65982-zx14-balance-shaft-adjustment

This is for ZX-14 but the setup on the C14 is the same.

Other things you might consider are extra heavy handlebar ends.  I added a pair of these to a Z750 I used to own and they worked great:

http://www.hvmp.com/Kawasaki-s/1.htm

Get the EXTRA heavy.  They are about 1# each and really make a difference.

A set of padded grips might also help you out.

[Rhino]

The inline 4-cylinder engine has what is called PRIMARY BALANCE by benefit of its design, so unlike a V-twin for example, they are generally smooth.  But they all suffer from a slight secondary imbalance as a general characteristic.  This is the purpose of the engine balancer that is in some inline 4 bikes including the C14.

The problem with secondary imbalance is that it's at 2X the rpm so it is often described as "buzz".  While carb and TB imbalance can cause it, I agree with the others that at the rpms you are talking about, that's probably not it.

You might check the balancer and this is adjustable.  It's possible it's not "tuned" just right for your bike.  The procedure is in the Svc Manual but you can also get a feel for it here:

http://zzrbikes.com/threads/65982-zx14-balance-shaft-adjustment

This is for ZX-14 but the setup on the C14 is the same.

Other things you might consider are extra heavy handlebar ends.  I added a pair of these to a Z750 I used to own and they worked great:

http://www.hvmp.com/Kawasaki-s/1.htm

Get the EXTRA heavy.  They are about 1# each and really make a difference.

A set of padded grips might also help you out.

  Good info! I never knew about this. It talks about hearing a "whirring" noise. I hear that on my bike all the time. I'm wondering if this is it and if I should attempt adjusting the balance shaft. I don't get any vibration as others have but I do get a high pitch "whirring" noise.

[gPink]

:good post: Good info! I never knew about this. It talks about hearing a "whirring" noise. I hear that on my bike all the time. I'm wondering if this is it and if I should attempt adjusting the balance shaft. I don't get any vibration as others have but I do get a high pitch "whirring" noise.

Turn the radio up 

[jwh20]

Good info! I never knew about this. It talks about hearing a "whirring" noise. I hear that on my bike all the time. I'm wondering if this is it and if I should attempt adjusting the balance shaft. I don't get any vibration as others have but I do get a high pitch "whirring" noise.

That's just the sound of power!!   

I'd leave it alone unless it's really loud.  There are plenty of other things that "whir" in a C14 engine, the crankshaft to clutch drive gear, the crankshaft to cam chain drive, the oil pump drive, and of course the balancer drive.

[maxtog]

You might check the balancer and this is adjustable.  It's possible it's not "tuned" just right for your bike.  The procedure is in the Svc Manual but you can also get a feel for it here:

http://zzrbikes.com/threads/65982-zx14-balance-shaft-adjustment

This is for ZX-14 but the setup on the C14 is the same.

I thought I read somewhere once that the C14 has a better or more complex or different balancing system than the ZX-14.   I am sure the concepts are similar, but am I remembering correctly?

[Rembrant]

You might check the balancer and this is adjustable.  It's possible it's not "tuned" just right for your bike.  The procedure is in the Svc Manual but you can also get a feel for it here:

http://zzrbikes.com/threads/65982-zx14-balance-shaft-adjustment

This is for ZX-14 but the setup on the C14 is the same.

I thought I read somewhere once that the C14 has a better or more complex or different balancing system than the ZX-14.   I am sure the concepts are similar, but am I remembering correctly?

Max,

As far as I know (or knew) the balancers are the same in both the ZX14 and the C14 (there are two per engine). If they're not identical, they are close to it. Like jwh mentions above they are externally adjustable, but all the adjustment does is change the balancer gearing backlash....it does not adjust how they balance. So, the adjustment will change the noise they make, but will make little to no difference in actual engine balancing.

Just as a side note...I wonder if these balancers are ever installed incorrectly in C14 engines? I have no personal experience with this, but I've read about a couple cases with ZX14 engines that were disassembled and at least one balancer shaft was found to be 180 degrees out of sync from the factory. The drag racing guys remove these balancer shafts and install plain "dummy" shafts in their places, so the engine guys do have experience with them...how they are supposed to be installed, and how an engine feels without them.

Rem

[Red Fox]

The most noticeable vibs I have on C14  are when I cover the brake lever with 2 fingers, a normal habit of mine.
So every so often I'm now removing my coverage of the brake lever in areas when I feel no risk.


On prior ST bike, an FJR1300, I went to a tune up meet with that bike specific 'experts' and volunteered to have my bike
used as a demo for throttle body sinc at 15,000.  4 cyl manometer and the whole 9-yds.
Tech doing it said he'd never seen such out of sync throttle bodies, yeah the manometers were widely different.  Fact.
He evened them up and said I'd feel so much more smoothness on the way home (30 miles). 
I did have to reduce the idle speed immediately after it was done.  But that's all.  So if you're an idling smoothness person, attack it. 
Smoothness/power, I never felt a benefit.  Never felt a benefit.  Never felt a benefit. 

Rode that bike to 78,000 and never addressed throttle bodies again.  What a waste of an afternoon,
except for the info I can pass on; like right here.

[tomp]

Simple fix, foam slip on grip covers.  I have used them on all my bikes for years, and they even helped on my Dyna.  No vibe feelings on the C14 with them. 

Two other benefits, they make the grips a larger diameter, lessening the "death grip cramps" that can happen with thinner/ narrower ones.  Also, they can be simply rolled off if you want to ride without them or use them on another bike.  I have one set that have been on three bikes with no problems or defects.  FWIW, heated grips still work fine, with the covers on the bike.

http://www.ebay.com/itm/Grab-On-Motorcycle-Grip-Covers-Foam-slip-on-Comfort-Sleeves-Anti-Vibration-/301306966382

[Son of Pappy]

It worked before, so maybe the "Non Calibration TB Calibration" may help?  Warm bike, turn off key in run position, 2 full twists of the throttle, key off, start and take a ride...

Ducking for cover

[maxtog]

Simple fix, foam slip on grip covers.  I have used them on all my bikes for years,

+1, me too.  The stock Concours grips are very thin and hard as a rock.

[jwh20]

Max,

As far as I know (or knew) the balancers are the same in both the ZX14 and the C14 (there are two per engine). If they're not identical, they are close to it. Like jwh mentions above they are externally adjustable, but all the adjustment does is change the balancer gearing backlash....it does not adjust how they balance. So, the adjustment will change the noise they make, but will make little to no difference in actual engine balancing.

Just as a side note...I wonder if these balancers are ever installed incorrectly in C14 engines? I have no personal experience with this, but I've read about a couple cases with ZX14 engines that were disassembled and at least one balancer shaft was found to be 180 degrees out of sync from the factory. The drag racing guys remove these balancer shafts and install plain "dummy" shafts in their places, so the engine guys do have experience with them...how they are supposed to be installed, and how an engine feels without them.

Rem

As best I can tell the balancers between the C14 and the ZX-14 are identical.  But even if different, the difference is slight.  Indeed there are timing marks on the balancers and on the crankshaft so that they can be correctly installed but do check or change you have to split the engine cases.  From looking at the service manual there is nothing but the marks to guide you on installation and unlike a cam chain/camshaft  installation mistake, nothing is going to hit and you'll just get more or different vibrations.  So I guess it's conceivable that the balancer could be improperly installed at the factory.

The adjustment just moves the gears closer or further away from each other so it controls the engagement.  This would affect the timing of the balancer slightly.  But I wouldn't expect a major difference from one extreme to the other.

[Jim H]

  When I first turn the key on I get the vibration from the tank while the fuel pump pressurizes....(at least this is what I believe that is) then it is pretty smooth until about 2500 to 3K or so and if I am against the tank seem to get it again.....normal?  Figured this was a good thread to ask since vibration is the topic. 

Jim

[VirginiaJim]

I've never felt anything from the tank..

[gggGary]

With high miles all I feel out my 08 is the "normal inline 4 buzz"  most noticeable from about 3K to well who the heck's paying attention to vibration once the tach has cleared 4K?

I can be a bit crude but these cheap fleabay grips made a world of difference.





They got rid of grip fatigue pronto especially since I have been solidly into heavy glove season since I got the bike.

[tomp]

With high miles all I feel out my 08 is the "normal inline 4 buzz"  most noticeable from about 3K to well who the heck's paying attention to vibration once the tach has cleared 4K?

I can be a bit crude but these cheap fleabay grips made a world of difference.





They got rid of grip fatigue pronto especially since I have been solidly into heavy glove season since I got the bike.

What, no link?  What's wrong wid chu?  Can't brag about a product and not let us go and see for ourselves.... tp
I use Grab On foam slip-on foam covers on all my bikes, and the've helped every time, what ever bike, and eliminated the "Death Grip", that happens often with small diameter grips, as well as vibrations, even with my Dyna. . . . . .
http://www.grabongrips.com/