TBS problem

[kiteflyer]

During my most recent TBS (12165 mi ) I couldn't get the #2 cylinder to sync up. The # 1,3 & 5 cylinders line up fine with the number 3 cylinder but the #2 cylinder is bouncing wildly. Regardless of with way I turn the screw, that readout remains bouncing. The idle drops although the adjustment screw is turned all the way clockwise to raise the idle. I am puzzled as to why the #2 cylinder bounces like it does. The air filter is clean, new spark plugs installed yet I can't get a successful TBS? Any thoughts or suggestions will be welcomed.

 

[escapefjrtist]

From the sounds of it you have the idle speed / air screw adjustments off relative to one another. I'd begin by adjusting all the air screws to 1 - 1-1/2 turns from bottom, adjust the idle speed to 1100 RPM and then sync so all the bodies read the same. Don't stress about using #3 for baseline, just make sure all TBs are equal. If the sync is way off don't forget to readjust the idle to 1100 RPM between each TB change.

Good luck.

--G

 

[TomInPA]

Do you have the damper (restrictor) in the hose for the #2 cylinder? If you swap one of the the hoses from the other cylinders does the erratic reading follow the swap? And where did you find Cyl #5?

 

[wfooshee]

And where did you find Cyl #5?

That's where Patriot mounted his air horn, isn't it??

 

[kiteflyer]

Do you have the damper (restrictor) in the hose for the #2 cylinder? If you swap one of the the hoses from the other cylinders does the erratic reading follow the swap? And where did you find Cyl #5?

I thought about swapping hoses, I try that next. The reference to cylinder #5 is a mistype: should read 4,. I think my first problem is the idle adjust screw. It is turned fully clockwise seems to have come that way in that this is the first time I've needed to touch it.

 

[TomInPA]

Just trying to eliminate the easy stuff first. If the air screw is all the way in and your gauge is working well, you might want to try Freds' really unauthorized TBS where the butteryflies are synced with the air screws closed, then the final adjustment is done opening all air screws one turn and a final adjustment on the air screws alone. Basically, the method eliminates any air-screw adjustment as a problem.

 

[escapefjrtist]

Another point. Before you dig in much deeper, definitely check Tom's idea of a missing restrictor, unless of course you've used the device prior to this with good success.

With the later GENIIs, the TBS rarely moves and needs to be be adjusted. We see a lot of bikes at the PNW Tech Days and the later model years very rarely need to be touched. I'd be wary of digging in with the unauthorized TBS as things can go downhill quickly...if it ain't broke don't fix it!

Let us know what you find.

--G

 

[bgross]

[quote name=escapefjrtist" post="1028238" time="1356890371]Another point. Before you dig in much deeper, definitely check Tom's idea of a missing restrictor, unless of course you've used the device prior to this with good success. With the later GENIIs, the TBS rarely moves and needs to be be adjusted. We see a lot of bikes at the PNW Tech Days and the later model years very rarely need to be touched. I'd be wary of digging in with the unauthorized TBS as things can go downhill quickly...if it ain't broke don't fix it! Let us know what you find. --G

To which years are you referring, please? 09-12? 10-12?

I realize that all generalizations are subject to some latitude, so I'm not asking for too fine a point on this. Just your experience & observations.

Others feel free to chime in, too.

Enquiring minds...

 

[Fred W]

First off, a bouncing reading is not something that will be effected by a TBS. The reason that one of the gauge channels is bouncing has to be a fault of the test equipment. So the idea about the restrictor being missing (or too large) is a good one.

Next, since you cannot raise your idle far enough to reach spec of 1100 rpm, this is telling you that the cumulative air of the 4 bypass channels is too little. The simplest way to correct this situation is to open all 4 of your air screws by an identical amount (say 1/2 turn) and then re-sync them to each other. Opening each air screw should cause the idle speed to increase and the vacuum of the channel being opened to drop. Make note that as you open each air screw you get the appropriate response on the vacuum gauge and idle. Some folks have had plugged-up air screw passages, which caused some difficulty in syncing. A spritz of carb cleaner into the removed air screw hole is usually all that is needed to clean that if you find that you have it.

There is nothing magic about #3 when doing a TBS, as all 4 throttle bodies have an air bypass screw. It is the source of much confusion. Your only goal is to get equal vacuum on all 4 channels. That's all. What the absolute vacuum level turns out to be is really of no concern. It will be whatever it will be at that idle speed, and your adjustments will have no effect on that.

My Unauthorized procedure linked to above by TominCA has proven to be a good one, and has netted improvements (in reduced engine vibrations) on all bikes we have tried it on, both first gens and second gens (even latest model years) and even when the standard TBS as performed by a dealer looks just fine.

YMMV

But, you do want to verify that your test equipment is reading correctly, so try swapping channels and noting if there is a change in the displayed vacuums.

 

[kamal]

Just trying to eliminate the easy stuff first. If the air screw is all the way in and your gauge is working well, you might want to try Freds' really unauthorized TBS where the butteryflies are synced with the air screws closed, then the final adjustment is done opening all air screws one turn and a final adjustment on the air screws alone. Basically, the method eliminates any air-screw adjustment as a problem.

+1 on this.

After removing all the PAIR stuff (to cure deceleration popping in my aftermarket cans), I did Fred's RUTBS - because I could. The bike was transformed from 'smooth' to 'turbine smooth'.

Al

 

[escapefjrtist]

Another point. Before you dig in much deeper, definitely check Tom's idea of a missing restrictor, unless of course you've used the device prior to this with good success. With the later GENIIs, the TBS rarely moves and needs to be be adjusted. We see a lot of bikes at the PNW Tech Days and the later model years very rarely need to be touched. I'd be wary of digging in with the unauthorized TBS as things can go downhill quickly...if it ain't broke don't fix it! Let us know what you find. --G

To which years are you referring, please? 09-12? 10-12?

I realize that all generalizations are subject to some latitude, so I'm not asking for too fine a point on this. Just your experience & observations.

My '06 was MUCH more stable than my '04 which seemed to be all over the place each time I plugged the sticks in. At our PNW Tech Meets, in general, the '08s and up seem to be very stable and rarely require any change(s). For grins we'll often try to make one better and then end up back where we started. We've probably checked 3 or 4 dozen later model FJRs and even those with miles (50 - 70K+) require no adjustment.

Definitely not a big enough sample to draw any conclusions, just my $.02.

Although I'm tempted to try Fred's RUTBS, my current '09 is so damn smooth, I just can't believe there's any improvement available.

YMMV

--G

 

[kiteflyer]

Thanks. There's a lot of good information in this thread. I'm going to try FredW's throttle plate method as soon as the 15 degree temps, the ice and snow melts and my time allows. Beginning to think that my vacuum tester is faulty on that number 2 cylinder port. I need to verify by comparing it to the other three ports and fix if necessary. Thanks again for the information.

 

[SouthernCruizer]

Another point. Before you dig in much deeper, definitely check Tom's idea of a missing restrictor, unless of course you've used the device prior to this with good success. With the later GENIIs, the TBS rarely moves and needs to be be adjusted. We see a lot of bikes at the PNW Tech Days and the later model years very rarely need to be touched. I'd be wary of digging in with the unauthorized TBS as things can go downhill quickly...if it ain't broke don't fix it! Let us know what you find. --G

To which years are you referring, please? 09-12? 10-12?

I realize that all generalizations are subject to some latitude, so I'm not asking for too fine a point on this. Just your experience & observations.

My '06 was MUCH more stable than my '04 which seemed to be all over the place each time I plugged the sticks in. At our PNW Tech Meets, in general, the '08s and up seem to be very stable and rarely require any change(s). For grins we'll often try to make one better and then end up back where we started. We've probably checked 3 or 4 dozen later model FJRs and even those with miles (50 - 70K+) require no adjustment.

Definitely not a big enough sample to draw any conclusions, just my $.02.

Although I'm tempted to try Fred's RUTBS, my current '09 is so damn smooth, I just can't believe there's any improvement available.

YMMV

--G

+1 on this...i check my '08 every time I change plugs, and the sync is almost spot on each time...as opposed to my '04, which required constant re-syncing.

 

[Fred W]

Out of curiosity, have you guys with the stable and smooth second gens ever looked at the vacuum levels with the 4 air screws closed down? If they are reasonable well aligned there would be no need to adjust the throttle plate linkage, just re-open the air screws and adjust as normal. But it would be interesting to know if the butterflies on bikes that people are happy with are already in sync.

FWIW, I did adjust a few 2nd gens at the last NERDS tech day, and each of the owners said that, although they were completely happy with their bikes before hand, they were still able to notice some added smoothness after the adjustment.

None of this is all that earth shaking. An owner could just ride his FJR its entire lifetime and never make the adjustment.

 

[SouthernCruizer]

Out of curiosity, have you guys with the stable and smooth second gens ever looked at the vacuum levels with the 4 air screws closed down? If they are reasonable well aligned there would be no need to adjust the throttle plate linkage, just re-open the air screws and adjust as normal. But it would be interesting to know if the butterflies on bikes that people are happy with are already in sync.

FWIW, I did adjust a few 2nd gens at the last NERDS tech day, and each of the owners said that, although they were completely happy with their bikes before hand, they were still able to notice some added smoothness after the adjustment.

None of this is all that earth shaking. An owner could just ride his FJR its entire lifetime and never make the adjustment.

You're probably right, could be a hair smoother, but knowing my luck, I fiddle with it and it gets worse. Pretty smooth already. But, its a moot point..just waiting for the '13s to get to my local dealer, and the '08 will be history.

 

[kiteflyer]

I have just realized that my ass is showing. In checking my Morgan Carbtool, while checking the restrictor tubes, I found that the #4 tube had one, the #3 tube had one, the #2 tube had none and the #1 tube had two. Jeez. I have found my problem. Thank you all for your help.

 

[escapefjrtist]

Easy problem to fix and Tom nailed it!

Glad it turned out to be that simple...

--G

 

[escapefjrtist]

Out of curiosity, have you guys with the stable and smooth second gens ever looked at the vacuum levels with the 4 air screws closed down? If they are reasonable well aligned there would be no need to adjust the throttle plate linkage, just re-open the air screws and adjust as normal. But it would be interesting to know if the butterflies on bikes that people are happy with are already in sync.

Never have looked at this Fred. I won't be into mine for another 10,000 miles but the PNW spring Tech Day will be here in a few months. If we find a willing participant, we'll check this out.

--G

 

[TomInPA]

I have just realized that my ass is showing. In checking my Morgan Carbtool, while checking the restrictor tubes, I found that the #4 tube had one, the #3 tube had one, the #2 tube had none and the #1 tube had two. Jeez. I have found my problem. Thank you all for your help.

Not gloating, but I gotta say, I told you so. Thanks for checking!